Mergeable.java

package org.theonefx.wcframework.ioc.val;

/**
 * Interface representing an object whose value set can be merged with
 * that of a parent object.
 */
public interface Mergeable {

	/**
	 * Is merging enabled for this particular instance?
	 */
	boolean isMergeEnabled();

	/**
	 * Merge the current value set with that of the supplied object.
	 * <p>The supplied object is considered the parent, and values in
	 * the callee's value set must override those of the supplied object.
	 * @param parent the object to merge with
	 * @return the result of the merge operation
	 * @throws IllegalArgumentException if the supplied parent is <code>null</code>
	 * @exception IllegalStateException if merging is not enabled for this instance
	 * (i.e. <code>mergeEnabled</code> equals <code>false</code>).
	 */
	Object merge(Object parent);

}