Add JavaDocs to unsupported AreaBreakRenderer methods

DEVSIX-4803

Author: introfog

layout/src/main/java/com/itextpdf/layout/renderer/AreaBreakRenderer.java

@@ -68,21 +68,39 @@ public AreaBreakRenderer(AreaBreak areaBreak) {
         this.areaBreak = areaBreak;
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @param renderer {@inheritDoc}
+     */
     @Override
     public void addChild(IRenderer renderer) {
-        throw new RuntimeException();
+        throw new UnsupportedOperationException();
     }
 
     @Override
     public LayoutResult layout(LayoutContext layoutContext) {
         return new LayoutResult(LayoutResult.NOTHING, null, null, null, this).setAreaBreak(areaBreak);
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @param drawContext {@inheritDoc}
+     */
     @Override
     public void draw(DrawContext drawContext) {
         throw new UnsupportedOperationException();
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @return {@inheritDoc}
+     */
     @Override
     public LayoutArea getOccupiedArea() {
         throw new UnsupportedOperationException();
@@ -113,11 +131,27 @@ public <T1> T1 getDefaultProperty(int property) {
         return (T1) (Object) null;
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @param property {@inheritDoc}
+     * @param defaultValue {@inheritDoc}
+     * @param <T1> {@inheritDoc}
+     * @return {@inheritDoc}
+     */
     @Override
     public <T1> T1 getProperty(int property, T1 defaultValue) {
         throw new UnsupportedOperationException();
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @param property {@inheritDoc}
+     * @param value {@inheritDoc}
+     */
     @Override
     public void setProperty(int property, Object value) {
         throw new UnsupportedOperationException();
@@ -150,6 +184,13 @@ public boolean isFlushed() {
         return false;
     }
 
+    /**
+     * Throws an UnsupportedOperationException because instances of this
+     * class are only used for terminating the current content area.
+     *
+     * @param dx {@inheritDoc}
+     * @param dy {@inheritDoc}
+     */
     @Override
     public void move(float dx, float dy) {
         throw new UnsupportedOperationException();