[MNG-4840] document requiredMavenVersion in plugin descriptor

Author: hboutemy

Diff for: api/maven-api-plugin/src/main/mdo/plugin.mdo

@@ -89,13 +89,19 @@ under the License.
         <field>
           <name>requiredJavaVersion</name>
           <version>1.1.0+</version>
-          <description>A version range which specifies the supported Java versions. A version range can either use the usual mathematical syntax "[2.0.10,2.1.0),[3.0,)" or use a single version "2.2.1". The latter is a short form for "[2.2.1,)", i.e. denotes the minimum version required.</description>
+          <description>
+            A version range which specifies the supported Java versions. A version range can either use the usual mathematical syntax "[2.0.10,2.1.0),[3.0,)" or use a single version "2.2.1". The latter is a short form for "[2.2.1,)", i.e. denotes the minimum version required.
+            @since Maven 4.0.0-alpha-3
+          </description>
           <type>String</type>
         </field>
         <field>
           <name>requiredMavenVersion</name>
-          <version>1.1.0+</version>
-          <description>A version range which specifies the supported Maven versions. A version range can either use the usual mathematical syntax "[2.0.10,2.1.0),[3.0,)" or use a single version "2.2.1". The latter is a short form for "[2.2.1,)", i.e. denotes the minimum version required. This value takes precedence over the POMs Maven prerequisite.</description>
+          <version>1.0.0+</version>
+          <description>
+            A version range which specifies the supported Maven versions. A version range can either use the usual mathematical syntax "[2.0.10,2.1.0),[3.0,)" or use a single version "2.2.1". The latter is a short form for "[2.2.1,)", i.e. denotes the minimum version required. This value takes precedence over the POMs Maven prerequisite.
+            @since Maven 3.0.2
+          </description>
           <type>String</type>
         </field>
         <field xdoc.separator="blank">

Diff for: maven-plugin-api/src/main/java/org/apache/maven/plugin/descriptor/PluginDescriptor.java

@@ -81,6 +81,7 @@ public class PluginDescriptor extends ComponentSetDescriptor implements Cloneabl
 
     private String description;
 
+    // MNG-4840
     private String requiredMavenVersion;
 
     private String requiredJavaVersion;
@@ -367,10 +368,22 @@ public String getDescription() {
         return description;
     }
 
+    /**
+     * Set required Maven version.
+     *
+     * @param requiredMavenVersion Maven version required by the plugin
+     * @since 3.0.2
+     */
     public void setRequiredMavenVersion(String requiredMavenVersion) {
         this.requiredMavenVersion = requiredMavenVersion;
     }
 
+    /**
+     * Get required Maven version.
+     *
+     * @return the Maven version required by the plugin
+     * @since 3.0.2
+     */
     public String getRequiredMavenVersion() {
         return requiredMavenVersion;
     }