feat: added some component properties

webcal/src/main/java/com/onixbyte/icalendar/CalendarUtil.java

@@ -17,6 +17,14 @@
 
 package com.onixbyte.icalendar;
 
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+import java.time.format.DateTimeFormatter;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Supplier;
+
 /**
  * CalendarUtil
  *

webcal/src/main/java/com/onixbyte/icalendar/calendar/property/Method.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.calendar.property;
 
-public enum Method implements CalendarProperty {
+public enum Method implements Property {
 
     PUBLISH("PUBLISH"),
     REQUEST("REQUEST"),

webcal/src/main/java/com/onixbyte/icalendar/calendar/property/ProductIdentifier.java

@@ -22,7 +22,7 @@ package com.onixbyte.icalendar.calendar.property;
  *
  * @author Zihlu WANG
  */
-public final class ProductIdentifier implements CalendarProperty {
+public final class ProductIdentifier implements Property {
 
     private final String value;
 

webcal/src/main/java/com/onixbyte/icalendar/calendar/property/Property.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.calendar.property;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
+import com.onixbyte.icalendar.property.Resolvable;
 
-public interface CalendarProperty extends CalendarResolvable {
+public interface Property extends Resolvable {
 }

webcal/src/main/java/com/onixbyte/icalendar/calendar/property/Scale.java

@@ -18,11 +18,11 @@
 package com.onixbyte.icalendar.calendar.property;
 
 /**
- * CalendarScale
+ * Scale
  *
  * @author Zihlu WANG
  */
-public enum CalendarScale implements CalendarProperty {
+public enum Scale implements Property {
 
     GREGORIAN,
     ;

webcal/src/main/java/com/onixbyte/icalendar/calendar/property/Version.java

@@ -22,7 +22,7 @@ package com.onixbyte.icalendar.calendar.property;
  *
  * @author Zihlu WANG
  */
-public enum Version implements CalendarProperty {
+public enum Version implements Property {
 
     VERSION_2_0,
     ;

webcal/src/main/java/com/onixbyte/icalendar/component/Calendar.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.component;
 
-import com.onixbyte.icalendar.calendar.property.CalendarScale;
+import com.onixbyte.icalendar.calendar.property.Scale;
 import com.onixbyte.icalendar.calendar.property.Method;
 import com.onixbyte.icalendar.calendar.property.ProductIdentifier;
 import com.onixbyte.icalendar.calendar.property.Version;
@@ -60,7 +60,7 @@ public final class Calendar {
     /**
      * This property are OPTIONAL, but MUST NOT occur more than once.
      */
-    private CalendarScale scale;
+    private Scale scale;
 
     /**
      * This property are OPTIONAL, but MUST NOT occur more than once.

webcal/src/main/java/com/onixbyte/icalendar/component/property/Attachment.java

@@ -20,6 +20,7 @@ package com.onixbyte.icalendar.component.property;
 import com.onixbyte.icalendar.property.parameter.FormatType;
 
 import java.net.URI;
+import java.util.Objects;
 import java.util.Optional;
 
 /**
@@ -27,21 +28,27 @@ import java.util.Optional;
  *
  * @author Zihlu WANG
  */
-public final class Attachment implements ComponentProperty {
+public record Attachment(FormatType formatType,
+                         URI uri,
+                         String content) implements ComponentProperty {
 
-    private FormatType formatType;
-
-    private URI uri;
+    private static final String PROPERTY_NAME = "ATTACH";
 
     @Override
     public String resolve() {
-        final var attachmentBuilder = new StringBuilder("ATTACH");
+        if (Objects.isNull(uri) && (Objects.isNull(content) || content.isBlank())) {
+            return null;
+        }
+
+        final var attachmentBuilder = new StringBuilder(PROPERTY_NAME);
 
         Optional.ofNullable(formatType)
-                .ifPresent((fmtType) -> attachmentBuilder.append(fmtType.resolve()));
+                .ifPresent((fmtType) -> attachmentBuilder.append(";").append(fmtType.resolve()));
 
-        attachmentBuilder.append(":")
-                .append(uri.toString());
+        Optional.ofNullable(uri).ifPresentOrElse(
+                (_uri) -> attachmentBuilder.append(":").append(_uri),
+                () -> attachmentBuilder.append(";ENCODING=BASE64;VALUE=BINARY:").append(content));
+        attachmentBuilder.append("\n");
 
         return attachmentBuilder.toString();
     }

webcal/src/main/java/com/onixbyte/icalendar/component/property/CalendarDuration.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import java.time.Duration;
+
+public record CalendarDuration(Duration duration) implements ComponentProperty {
+
+    private static final String PROPERTY_NAME = "DURATION";
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + duration.toString() + "\n";
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Categories.java

@@ -17,5 +17,49 @@
 
 package com.onixbyte.icalendar.component.property;
 
-public class Categories {
+import java.util.ArrayList;
+import java.util.List;
+
+public final class Categories implements ComponentProperty {
+
+    private static final String PROPERTY_NAME = "CATEGORIES";
+
+    private final List<String> value;
+
+    private Categories(List<String> value) {
+        this.value = value;
+    }
+
+    public static class Builder {
+        private List<String> categories;
+
+        private Builder() {
+            categories = new ArrayList<>();
+        }
+
+        public Builder addCategory(String category) {
+            if (!categories.contains(category)) {
+                categories.add(category);
+            }
+            return this;
+        }
+
+        public Builder addCategories(List<String> categories) {
+            categories.forEach(this::addCategory);
+            return this;
+        }
+
+        public Categories build() {
+            return new Categories(categories);
+        }
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + String.join(",", value) + "\n";
+    }
 }

webcal/src/main/java/com/onixbyte/icalendar/component/property/Classification.java

@@ -17,5 +17,17 @@
 
 package com.onixbyte.icalendar.component.property;
 
-public enum Classification {
+public enum Classification implements ComponentProperty {
+
+    PUBLIC,
+    PRIVATE,
+    CONFIDENTIAL,
+    ;
+
+    private static final String PROPERTY_NAME = "CLASS";
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + name() + "\n";
+    }
 }

webcal/src/main/java/com/onixbyte/icalendar/component/property/Comment.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public record Comment(AlternateRepresentation altRep,
+                      Language language,
+                      String value) implements TextProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "COMMENT";
+
+    @Override
+    public String resolve() {
+        return composeResolution(PROPERTY_NAME, altRep, language, value);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/ComponentProperty.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.component.property;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
+import com.onixbyte.icalendar.property.Resolvable;
 
-public interface ComponentProperty extends CalendarResolvable {
+public interface ComponentProperty extends Resolvable {
 }

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeCompleted.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+
+public record DateTimeCompleted(LocalDateTime value) implements DateTimeProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "COMPLETED";
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + value
+                .atZone(ZoneId.systemDefault())
+                .withZoneSameInstant(ZoneId.of("UTC"))
+                .format(DateTimeProperty.utcDateTimeFormatter());
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeDue.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+import com.onixbyte.icalendar.property.parameter.ValueDataType;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+public record DateTimeDue(ValueDataType valueDataType,
+                          LocalDateTime localDateTime) implements DateTimeProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "DUE";
+
+    public DateTimeDue {
+        if (Objects.nonNull(valueDataType) && !SUPPORTED_VALUES.contains(valueDataType)) {
+            throw new IllegalArgumentException("ValueDateType only accepts DATE and DATE-TIME");
+        }
+    }
+
+    @Override
+    public String resolve() {
+        return DateTimeProperty.composeResolution(PROPERTY_NAME, valueDataType, localDateTime);
+    }
+
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeEnd.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.property.parameter.ValueDataType;
+
+import java.time.LocalDateTime;
+import java.util.Objects;
+import java.util.Optional;
+
+public record DateTimeEnd(ValueDataType valueDataType,
+                          LocalDateTime localDateTime) implements DateTimeProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "DTEND";
+
+    public DateTimeEnd {
+        if (Objects.nonNull(valueDataType) && !SUPPORTED_VALUES.contains(valueDataType)) {
+            throw new IllegalArgumentException("ValueDateType only accepts DATE and DATE-TIME");
+        }
+    }
+
+    @Override
+    public String resolve() {
+        return DateTimeProperty.composeResolution(PROPERTY_NAME, valueDataType, localDateTime);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeProperty.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+import com.onixbyte.icalendar.property.parameter.ValueDataType;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+public interface DateTimeProperty {
+
+    List<ValueDataType> SUPPORTED_VALUES = List.of(
+            ValueDataType.DATE,
+            ValueDataType.DATE_TIME
+    );
+
+    DateTimeFormatter utcDateTimeFormatter = DateTimeFormatter.ofPattern("yyyyMMdd'T'HHmmss'Z'");
+
+    DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("yyyyMMdd");
+
+    static DateTimeFormatter utcDateTimeFormatter() {
+        return utcDateTimeFormatter;
+    }
+
+    static DateTimeFormatter dateFormatter() {
+        return dateFormatter;
+    }
+
+    static String composeResolution(String propertyName,
+                                    ValueDataType valueDataType,
+                                    LocalDateTime localDateTime) {
+        var dateTimeEndBuilder = new StringBuilder(propertyName);
+
+        Optional.ofNullable(valueDataType)
+                .filter(SUPPORTED_VALUES::contains)
+                .ifPresent((value) -> dateTimeEndBuilder.append(";").append(value.resolve()));
+
+        var dateTimeFormatter = switch (Optional.ofNullable(valueDataType)
+                .filter(SUPPORTED_VALUES::contains)
+                .orElse(ValueDataType.DATE_TIME)) {
+            case DATE -> dateFormatter;
+            case BINARY, UTC_OFFSET, BOOLEAN, CAL_ADDRESS, DURATION, FLOAT, INTEGER, PERIOD,
+                 RECURRENCE_RULE, TEXT, URI, DATE_TIME -> utcDateTimeFormatter;
+        };
+
+        dateTimeEndBuilder.append(":").append(localDateTime.format(dateTimeFormatter)).append("\n");
+        return dateTimeEndBuilder.toString();
+    }
+
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeStamp.java

@@ -23,65 +23,34 @@ import com.onixbyte.icalendar.config.Formatters;
 import java.time.LocalDateTime;
 
 /**
- * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that specifies a "{@link
- * Method Method}" property, this property specifies the date and time that
- * the instance of the {@link com.onixbyte.icalendar.component.Calendar iCalendar} object was created. In the case of
- * an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that doesn't specify a "{@link
- * Method Method}" property, this property specifies the date and time that
+ * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that
+ * specifies a "{@link Method Method}" property, this property specifies the date and time that the
+ * instance of the {@link com.onixbyte.icalendar.component.Calendar iCalendar} object was created.
+ * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that doesn't
+ * specify a "{@link Method Method}" property, this property specifies the date and time that
  * the information associated with the calendar component was last revised in the calendar store.
  * <p>
  * The value MUST be specified in the UTC time format.
  * <p>
- * This property is also useful to protocols such as [2447bis] that have inherent latency issues with the delivery of
- * content. This property will assist in the proper sequencing of messages containing {@link
- * com.onixbyte.icalendar.component.Calendar iCalendar} objects.
+ * This property is also useful to protocols such as [2447bis] that have inherent latency issues
+ * with the delivery of content. This property will assist in the proper sequencing of messages
+ * containing {@link com.onixbyte.icalendar.component.Calendar iCalendar} objects.
  * <p>
- * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that specifies a "{@link
- * Method Method}" property, this property differs from the "{@link
- * DateTimeCreated CREATED}" and "{@link LastModified LAST-MODIFIED}" properties. These two properties are used to
- * specify when the particular calendar data in the calendar store was created and last modified. This is different
- * from when the {@link com.onixbyte.icalendar.component.Calendar iCalendar} object representation of the calendar
+ * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that
+ * specifies a "{@link Method Method}" property, this property differs from the
+ * "{@link DateTimeCreated CREATED}" and "{@link LastModified LAST-MODIFIED}" properties. These two
+ * properties are used to specify when the particular calendar data in the calendar store was
+ * created and last modified. This is different from when the {@link
+ * com.onixbyte.icalendar.component.Calendar iCalendar} object representation of the calendar
  * service information was created or last modified.
  * <p>
- * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that specifies a "{@link
- * Method METHOD}" property, this property is equivalent to the "{@link
+ * In the case of an {@link com.onixbyte.icalendar.component.Calendar iCalendar} object that
+ * specifies a "{@link Method METHOD}" property, this property is equivalent to the "{@link
  * LastModified LAST-MODIFIED}" property.
  *
  * @author Zihlu WANG
  */
-public final class DateTimeStamp implements ComponentProperty {
-
-    private static final String PROPERTY_NAME = "DTSTAMP";
-
-    private LocalDateTime value;
-
-    public DateTimeStamp(LocalDateTime value) {
-        this.value = value;
-    }
-
-    public DateTimeStamp() {
-        this.value = LocalDateTime.now();
-    }
-
-    @Override
-    public String resolve() {
-        return PROPERTY_NAME + ":" + Formatters.getUtcDatetimeFormatter().format(value) + '\n';
-    }
-
-    public static class Builder {
-        private final DateTimeStamp dateTimeStamp = new DateTimeStamp();
-
-        public Builder dateTimeStamp(LocalDateTime dateTime) {
-            this.dateTimeStamp.value = dateTime;
-            return this;
-        }
-
-        public DateTimeStamp build() {
-            return dateTimeStamp;
-        }
-    }
-
-    public static Builder builder() {
-        return new Builder();
-    }
-}
+// public final class DateTimeStamp implements DateTimeProperty, ComponentProperty {
+//
+//
+// }

webcal/src/main/java/com/onixbyte/icalendar/component/property/DateTimeStart.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.property.parameter.ValueDataType;
+
+import java.time.LocalDateTime;
+import java.util.Objects;
+
+public record DateTimeStart(ValueDataType valueDataType,
+                            LocalDateTime localDateTime) implements DateTimeProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "DTSTART";
+
+    public DateTimeStart {
+        if (Objects.nonNull(valueDataType) && !SUPPORTED_VALUES.contains(valueDataType)) {
+            throw new IllegalArgumentException("ValueDateType only accepts DATE and DATE-TIME");
+        }
+    }
+
+    @Override
+    public String resolve() {
+        return DateTimeProperty.composeResolution(PROPERTY_NAME, valueDataType, localDateTime);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Description.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+public record Description(AlternateRepresentation altRep,
+                          Language language,
+                          String value) implements TextProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "DESCRIPTION";
+
+    @Override
+    public String resolve() {
+        return composeResolution(PROPERTY_NAME, altRep, language, value);
+    }
+
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/FreeBusyTime.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.datatype.Period;
+import com.onixbyte.icalendar.property.parameter.FreeBusyTimeType;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public final class FreeBusyTime implements ComponentProperty {
+
+    private static final String PROPERTY_NAME = "FREEBUSY";
+
+    private final FreeBusyTimeType freeBusyType;
+
+    private final List<Period> freeBusyValue;
+
+    public static class Builder {
+        public Builder freeBusyType(FreeBusyTimeType freeBusyType) {
+            this.freeBusyType = freeBusyType;
+            return this;
+        }
+
+        public Builder addFreeBusyValue(Period period) {
+            this.freeBusyValue.add(period);
+            return this;
+        }
+
+        public FreeBusyTime build() {
+            return new FreeBusyTime(freeBusyType, freeBusyValue);
+        }
+
+        private FreeBusyTimeType freeBusyType;
+
+        private List<Period> freeBusyValue;
+
+        private Builder() {
+            this.freeBusyValue = new ArrayList<>();
+        }
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public String resolve() {
+        var freeBusyBuilder = new StringBuilder(PROPERTY_NAME);
+
+        Optional.ofNullable(freeBusyType)
+                .ifPresent((type) -> freeBusyBuilder.append(";").append(type.resolve()));
+
+        freeBusyBuilder.append(":").append(String.join(",", freeBusyValue
+                .stream()
+                .map(Period::resolve)
+                .toList()));
+
+        return freeBusyBuilder.toString();
+    }
+
+    private FreeBusyTime(FreeBusyTimeType freeBusyType, List<Period> freeBusyValue) {
+        this.freeBusyType = freeBusyType;
+        this.freeBusyValue = freeBusyValue;
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/GeoPosition.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+public record GeoPosition(double latitude,
+                          double longitude) implements ComponentProperty {
+
+    public GeoPosition {
+        if (latitude < -90 || latitude > 90) {
+            throw new IllegalArgumentException(
+                    "Latitude (%f) should greater than -90 and less than 90.".formatted(latitude));
+        }
+
+        if (longitude < -180 || longitude > 180) {
+            throw new IllegalArgumentException(
+                    "Longitude (%f) should greater than -180 and less than 180."
+                            .formatted(longitude));
+        }
+    }
+
+    private static final String PROPERTY_NAME = "GEO";
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + latitude + ";" + longitude + "\n";
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Location.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.CalendarUtil;
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+public record Location(AlternateRepresentation altRep,
+                       Language language,
+                       String value) implements TextProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "LOCATION";
+
+    @Override
+    public String resolve() {
+        return composeResolution(PROPERTY_NAME, altRep, language, value);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/PercentComplete.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+public record PercentComplete(int value) implements ComponentProperty {
+
+    public PercentComplete {
+        if (value < 0 || value > 100) {
+            throw new IllegalArgumentException("PercentComplete only accept value from 0 to 100, the given value %d is not acceptable."
+                    .formatted(value));
+        }
+    }
+
+    private static final String PROPERTY_NAME = "PERCENT-COMPLETE";
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + value + "\n";
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Priority.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+public record Priority(int value) implements ComponentProperty {
+
+    private static final String PROPERTY_NAME = "PRIORITY";
+
+    public Priority {
+        if (value < 0 || value > 9) {
+            throw new IllegalArgumentException("Priority %d is exceeded the range of 0-9.".formatted(value));
+        }
+    }
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + value + "\n";
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Resources.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public final class Resources implements TextProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "RESOURCES";
+
+    private final AlternateRepresentation altRep;
+
+    private final Language language;
+
+    private final List<String> value;
+
+    private Resources(AlternateRepresentation altRep, Language language, List<String> value) {
+        this.altRep = altRep;
+        this.language = language;
+        this.value = value;
+    }
+
+    public static class Builder {
+        private List<String> value;
+
+        private AlternateRepresentation altRep;
+
+        private Language language;
+
+        private Builder() {
+            this.value = new ArrayList<>();
+        }
+
+        public Builder altRep(AlternateRepresentation altRep) {
+            this.altRep = altRep;
+            return this;
+        }
+
+        public Builder language(Language language) {
+            this.language = language;
+            return this;
+        }
+
+        public Builder addResource(String resource) {
+            value.add(resource);
+            return this;
+        }
+
+        public Builder addResources(List<String> resources) {
+            value.addAll(resources);
+            return this;
+        }
+
+        public Resources build() {
+            return new Resources(altRep, language, value);
+        }
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    @Override
+    public String resolve() {
+        return composeResolution(PROPERTY_NAME, altRep, language, () -> String.join(",", value));
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Status.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import java.util.List;
+
+public enum Status implements ComponentProperty {
+
+    TENTATIVE("TENTATIVE"),
+    CONFIRMED("CONFIRMED"),
+    CANCELLED("CANCELLED"),
+    NEEDS_ACTION("NEEDS-ACTION"),
+    COMPLETED("COMPLETED"),
+    IN_PROGRESS("IN-PROGRESS"),
+    DRAFT("DRAFT"),
+    FINAL("FINAL"),
+    ;
+
+    private static final String PROPERTY_NAME = "STATUS";
+
+    private final String tag;
+
+    Status(String tag) {
+        this.tag = tag;
+    }
+
+    @Override
+    public String resolve() {
+        return PROPERTY_NAME + ":" + tag + "\n";
+    }
+
+    public static List<Status> eventStatus() {
+        return List.of(TENTATIVE, CONFIRMED, CANCELLED);
+    }
+
+    public static List<Status> todoStatus() {
+        return List.of(NEEDS_ACTION, COMPLETED, IN_PROGRESS, CANCELLED);
+    }
+
+    public static List<Status> journalStatus() {
+        return List.of(DRAFT, FINAL, CANCELLED);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/Summary.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+public record Summary(AlternateRepresentation altRep,
+                      Language language,
+                      String value) implements TextProperty, ComponentProperty {
+
+    private static final String PROPERTY_NAME = "SUMMARY";
+
+    @Override
+    public String resolve() {
+        return composeResolution(PROPERTY_NAME, altRep, language, value);
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/TextProperty.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.component.property;
+
+import com.onixbyte.icalendar.property.parameter.AlternateRepresentation;
+import com.onixbyte.icalendar.property.parameter.Language;
+
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public interface TextProperty {
+
+    default String composeResolution(String propertyName,
+                                     AlternateRepresentation altRep,
+                                     Language language,
+                                     String value) {
+        if (Objects.isNull(value) || value.isBlank()) {
+            return null;
+        }
+
+        var resolutionBuilder = new StringBuilder(propertyName);
+
+        Optional.ofNullable(altRep)
+                .ifPresent((_altRep) -> resolutionBuilder.append(";").append(_altRep.resolve()));
+
+        Optional.ofNullable(language)
+                .ifPresent((lang) -> resolutionBuilder.append(";").append(lang.resolve()));
+
+        resolutionBuilder.append(":")
+                .append(value)
+                .append("\n");
+
+        return resolutionBuilder.toString();
+    }
+
+    default String composeResolution(String propertyName,
+                                     AlternateRepresentation altRep,
+                                     Language language,
+                                     Supplier<String> valueSupplier) {
+        return composeResolution(propertyName, altRep, language, valueSupplier.get());
+    }
+
+}

webcal/src/main/java/com/onixbyte/icalendar/component/property/UniqueIdentifier.java

@@ -22,42 +22,7 @@ package com.onixbyte.icalendar.component.property;
  *
  * @author Zihlu WANG
  */
-public final class UniqueIdentifier implements ComponentProperty {
-
-    private String value;
-
-    private UniqueIdentifier() {
-    }
-
-    private void setValue(String value) {
-        this.value = value;
-    }
-
-    public static class Builder {
-        private final UniqueIdentifier uniqueIdentifier;
-
-        private Builder() {
-            this.uniqueIdentifier = new UniqueIdentifier();
-        }
-
-        public Builder uniqueIdentifier(String uniqueIdentifier) {
-            this.uniqueIdentifier.value = uniqueIdentifier;
-            return this;
-        }
-
-        public Builder uniqueIdentifier(String uniqueIdentifier, String domainName) {
-            this.uniqueIdentifier.value = uniqueIdentifier + "@" + domainName;
-            return this;
-        }
-
-        public UniqueIdentifier build() {
-            return uniqueIdentifier;
-        }
-    }
-
-    public static Builder builder() {
-        return new Builder();
-    }
+public record UniqueIdentifier(String value) implements ComponentProperty {
 
     @Override
     public String resolve() {

webcal/src/main/java/com/onixbyte/icalendar/datatype/CalendarUserAddress.java

@@ -17,9 +17,11 @@
 
 package com.onixbyte.icalendar.datatype;
 
+import com.onixbyte.icalendar.property.Resolvable;
+
 import java.net.URI;
 
-public final class CalendarUserAddress  {
+public final class CalendarUserAddress implements Resolvable {
 
     private URI value;
 
@@ -38,6 +40,11 @@ public final class CalendarUserAddress  {
         this.value = uri;
     }
 
+    @Override
+    public String resolve() {
+        return toString();
+    }
+
     @Override
     public String toString() {
         return value.toString();

webcal/src/main/java/com/onixbyte/icalendar/datatype/Period.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.datatype;
+
+import com.onixbyte.icalendar.property.Resolvable;
+
+public interface Period extends Resolvable {
+
+}

webcal/src/main/java/com/onixbyte/icalendar/datatype/PeriodExplicit.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.datatype;
+
+import com.onixbyte.icalendar.component.property.DateTimeProperty;
+import com.onixbyte.icalendar.property.Resolvable;
+
+import java.time.LocalDateTime;
+
+public final class PeriodExplicit implements Period {
+
+    private final LocalDateTime startTime;
+
+    private final LocalDateTime endTime;
+
+    public PeriodExplicit(LocalDateTime startTime, LocalDateTime endTime) {
+        if (startTime.isAfter(endTime)) {
+            throw new IllegalArgumentException("Period start must not after than period end.");
+        }
+        this.startTime = startTime;
+        this.endTime = endTime;
+    }
+
+    @Override
+    public String resolve() {
+        return startTime.format(DateTimeProperty.utcDateTimeFormatter()) + "/" +
+                endTime.format(DateTimeProperty.utcDateTimeFormatter());
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/datatype/PeriodStart.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2024-2024 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.onixbyte.icalendar.datatype;
+
+import com.onixbyte.icalendar.component.property.DateTimeProperty;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+
+public final class PeriodStart implements Period {
+
+    private LocalDateTime start;
+
+    private Duration duration;
+
+    @Override
+    public String resolve() {
+        return start.format(DateTimeProperty.utcDateTimeFormatter()) + "/" + duration;
+    }
+}

webcal/src/main/java/com/onixbyte/icalendar/property/Resolvable.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.property;
 
-public interface CalendarResolvable {
+public interface Resolvable {
 
     String resolve();
 

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/AlarmTriggerRelationship.java

@@ -28,10 +28,10 @@ public enum AlarmTriggerRelationship implements PropertyParameter {
     END
     ;
 
-    private static final String PROPERTY_NAME = "RELATED";
+    private static final String PARAMETER_NAME = "RELATED";
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + name();
+        return PARAMETER_NAME + "=" + name();
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/AlternateRepresentation.java

@@ -17,8 +17,6 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
-
 import java.net.URI;
 
 /**
@@ -35,7 +33,7 @@ import java.net.URI;
  */
 public final class AlternateRepresentation implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "ALTREP";
+    private static final String PARAMETER_NAME = "ALTREP";
 
     private final URI value;
 
@@ -45,7 +43,7 @@ public final class AlternateRepresentation implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=\"" + value.toString() + "\"";
+        return PARAMETER_NAME + "=\"" + value.toString() + "\"";
     }
 
     public static class Builder {

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/CommonName.java

@@ -17,8 +17,6 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
-
 /**
  * Common Name can be specified on properties with a CAL-ADDRESS value type. The parameter
  * specifies the common name to be associated with the calendar user specified by the property.
@@ -29,7 +27,7 @@ import com.onixbyte.icalendar.property.CalendarResolvable;
  */
 public final class CommonName implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "CN";
+    private static final String PARAMETER_NAME = "CN";
 
     private final String value;
 
@@ -59,6 +57,6 @@ public final class CommonName implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=\"" + this.value + "\"";
+        return PARAMETER_NAME + "=\"" + this.value + "\"";
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/Delegatee.java

@@ -31,7 +31,7 @@ import java.util.function.Supplier;
  */
 public final class Delegatee implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "DELEGATED-TO";
+    private static final String PARAMETER_NAME = "DELEGATED-TO";
 
     private final List<CalendarUserAddress> value;
 
@@ -82,7 +82,7 @@ public final class Delegatee implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + String.join(",", value.stream()
+        return PARAMETER_NAME + "=" + String.join(",", value.stream()
                 .map((_value) -> "\"" + _value + "\"")
                 .toList());
     }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/Delegator.java

@@ -18,7 +18,6 @@
 package com.onixbyte.icalendar.property.parameter;
 
 import com.onixbyte.icalendar.datatype.CalendarUserAddress;
-import com.onixbyte.icalendar.property.CalendarResolvable;
 
 import java.net.URI;
 import java.util.ArrayList;
@@ -32,7 +31,7 @@ import java.util.function.Supplier;
  */
 public final class Delegator implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "DELEGATED-FROM";
+    private static final String PARAMETER_NAME = "DELEGATED-FROM";
 
     private List<CalendarUserAddress> value;
 
@@ -83,7 +82,7 @@ public final class Delegator implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=\"" + String.join(",", value.stream()
+        return PARAMETER_NAME + "=\"" + String.join(",", value.stream()
                 .map((_value) -> "\"" + _value + "\"")
                 .toList()) + "\"";
     }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/DirectoryEntryReference.java

@@ -26,7 +26,7 @@ import java.net.URI;
  */
 public final class DirectoryEntryReference implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "DIR";
+    private static final String PARAMETER_NAME = "DIR";
 
     private final URI value;
 
@@ -61,6 +61,6 @@ public final class DirectoryEntryReference implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=\"" + value + "\"";
+        return PARAMETER_NAME + "=\"" + value + "\"";
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/FormatType.java

@@ -17,8 +17,6 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
-
 /**
  * FormatType
  *
@@ -30,7 +28,7 @@ public enum FormatType implements PropertyParameter {
 
     ;
 
-    private static final String PROPERTY_NAME = "FMTTYPE";
+    private static final String PARAMETER_NAME = "FMTTYPE";
 
     private final String ianaRegistry;
 
@@ -40,6 +38,6 @@ public enum FormatType implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + this.ianaRegistry;
+        return PARAMETER_NAME + "=" + this.ianaRegistry;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/FreeBusyTimeType.java

@@ -30,7 +30,7 @@ public enum FreeBusyTimeType implements PropertyParameter {
     BUSY_TENTATIVE("BUSY-TENTATIVE")
     ;
 
-    private static final String PROPERTY_NAME = "FBTYPE";
+    private static final String PARAMETER_NAME = "FBTYPE";
 
     private final String tag;
 
@@ -40,6 +40,6 @@ public enum FreeBusyTimeType implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/GroupOrListMembership.java

@@ -31,7 +31,7 @@ import java.util.function.Supplier;
  */
 public final class GroupOrListMembership implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "MEMBER";
+    private static final String PARAMETER_NAME = "MEMBER";
 
     private final List<CalendarUserAddress> value;
 
@@ -82,7 +82,7 @@ public final class GroupOrListMembership implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + String.join(",", value.stream()
+        return PARAMETER_NAME + "=" + String.join(",", value.stream()
                 .map((_value) -> "\"" + _value + "\"")
                 .toList());
     }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/InlineEncoding.java

@@ -35,10 +35,10 @@ public enum InlineEncoding implements PropertyParameter {
         this.tag = tag;
     }
 
-    private static final String PROPERTY_NAME = "ENCODING";
+    private static final String PARAMETER_NAME = "ENCODING";
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/Language.java

@@ -17,8 +17,6 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
-
 /**
  * Language
  *
@@ -260,7 +258,7 @@ public enum Language implements PropertyParameter {
     SOUTH_AFRICA_ZULU("zu-ZA")
     ;
 
-    private static final String PROPERTY_NAME = "LANGUAGE";
+    private static final String PARAMETER_NAME = "LANGUAGE";
 
     private final String value;
 
@@ -270,6 +268,6 @@ public enum Language implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + value;
+        return PARAMETER_NAME + "=" + value;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/ParticipationRole.java

@@ -30,7 +30,7 @@ public enum ParticipationRole implements PropertyParameter {
     NON_PARTICIPANT("NON-PARTICIPANT"),
     ;
 
-    private static final String PROPERTY_NAME = "ROLE";
+    private static final String PARAMETER_NAME = "ROLE";
 
     private final String tag;
 
@@ -40,6 +40,6 @@ public enum ParticipationRole implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/ParticipationStatus.java

@@ -47,7 +47,7 @@ public enum ParticipationStatus implements PropertyParameter {
         return List.of(NEEDS_ACTION, ACCEPTED, DECLINED);
     }
 
-    private static final String PROPERTY_NAME = "PARTSTAT";
+    private static final String PARAMETER_NAME = "PARTSTAT";
 
     private final String tag;
 
@@ -57,6 +57,6 @@ public enum ParticipationStatus implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/PropertyParameter.java

@@ -17,7 +17,7 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
+import com.onixbyte.icalendar.property.Resolvable;
 
-public interface PropertyParameter extends CalendarResolvable {
+public interface PropertyParameter extends Resolvable {
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/RecurrenceIdentifierRange.java

@@ -27,7 +27,7 @@ public enum RecurrenceIdentifierRange implements PropertyParameter {
     THIS_AND_FUTURE("THISANDFUTURE")
     ;
 
-    private static final String PROPERTY_NAME = "RANGE";
+    private static final String PARAMETER_NAME = "RANGE";
 
     private final String tag;
 
@@ -37,6 +37,6 @@ public enum RecurrenceIdentifierRange implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/RelationshipType.java

@@ -39,7 +39,7 @@ public enum RelationshipType implements PropertyParameter {
     START_TO_START("STARTTOSTART")
     ;
 
-    private static final String PROPERTY_NAME = "RELTYPE";
+    private static final String PARAMETER_NAME = "RELTYPE";
 
     private final String tag;
 
@@ -49,6 +49,6 @@ public enum RelationshipType implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + tag;
+        return PARAMETER_NAME + "=" + tag;
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/RsvpExpectation.java

@@ -24,7 +24,7 @@ package com.onixbyte.icalendar.property.parameter;
  */
 public final class RsvpExpectation implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "RSVP";
+    private static final String PARAMETER_NAME = "RSVP";
 
     private final boolean value;
 
@@ -34,6 +34,6 @@ public final class RsvpExpectation implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + String.valueOf(value).toUpperCase();
+        return PARAMETER_NAME + "=" + String.valueOf(value).toUpperCase();
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/SentBy.java

@@ -28,7 +28,7 @@ import java.net.URI;
  */
 public final class SentBy implements PropertyParameter {
 
-    private static final String PROPERTY_NAME = "SENT-BY";
+    private static final String PARAMETER_NAME = "SENT-BY";
 
     private final CalendarUserAddress value;
 
@@ -68,6 +68,6 @@ public final class SentBy implements PropertyParameter {
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=\"" + value + "\"";
+        return PARAMETER_NAME + "=\"" + value + "\"";
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/UserType.java

@@ -17,14 +17,12 @@
 
 package com.onixbyte.icalendar.property.parameter;
 
-import com.onixbyte.icalendar.property.CalendarResolvable;
-
 /**
- * CalendarUserType
+ * UserType
  *
  * @author Zihlu WANG
  */
-public enum CalendarUserType implements PropertyParameter {
+public enum UserType implements PropertyParameter {
 
     /**
      * An individual.
@@ -52,10 +50,10 @@ public enum CalendarUserType implements PropertyParameter {
     UNKNOWN,
     ;
 
-    private static final String PROPERTY_NAME = "CUTYPE";
+    private static final String PARAMETER_NAME = "CUTYPE";
 
     @Override
     public String resolve() {
-        return PROPERTY_NAME + "=" + this.name();
+        return PARAMETER_NAME + "=" + this.name();
     }
 }

webcal/src/main/java/com/onixbyte/icalendar/property/parameter/ValueDataType.java

@@ -22,5 +22,33 @@ package com.onixbyte.icalendar.property.parameter;
  *
  * @author Zihlu WANG
  */
-public class ValueDataType {
+public enum ValueDataType implements PropertyParameter {
+
+    BINARY("BINARY"),
+    BOOLEAN("BOOLEAN"),
+    CAL_ADDRESS("CAL-ADDRESS"),
+    DATE("DATE"),
+    DATE_TIME("DATE-TIME"),
+    DURATION("DURATION"),
+    FLOAT("FLOAT"),
+    INTEGER("INTEGER"),
+    PERIOD("PERIOD"),
+    RECURRENCE_RULE("RECUR"),
+    TEXT("TEXT"),
+    URI("URI"),
+    UTC_OFFSET("UTC-OFFSET"),
+    ;
+
+    private static final String PARAMETER_NAME = "VALUE";
+
+    private final String tag;
+
+    ValueDataType(String tag) {
+        this.tag = tag;
+    }
+
+    @Override
+    public String resolve() {
+        return PARAMETER_NAME + "=" + tag;
+    }
 }