/**
 * @(#)AnnotationProcessors.java	1.2 04/06/21
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.mirror.apt;

import com.sun.mirror.apt.*;
import java.util.*;

/**
 * Utilities to create specialized annotation processors.
 *
 * @since 1.5
 * @author Joseph D. Darcy
 * @author Scott Seligman
 */
public class AnnotationProcessors {
    static class NoOpAP implements AnnotationProcessor {
	NoOpAP() {}
	public void process(){}
    }

    /**
     * Combines multiple annotation processors into a simple composite
     * processor.
     * The composite processor functions by invoking each of its component
     * processors in sequence.
     */
    static class CompositeAnnotationProcessor implements AnnotationProcessor {
    
	private List<AnnotationProcessor> aps = 
	    new LinkedList<AnnotationProcessor>();

	/**
	 * Constructs a new composite annotation processor.
	 * @param aps  the component annotation processors
	 */
	public CompositeAnnotationProcessor(Collection<AnnotationProcessor> aps) {
	    this.aps.addAll(aps);
	}

	/**
	 * Constructs a new composite annotation processor.
	 * @param aps  the component annotation processors
	 */
	public CompositeAnnotationProcessor(AnnotationProcessor... aps) {
	    for(AnnotationProcessor ap: aps)
		this.aps.add(ap);
	}

	/**
	 * Invokes the <tt>process</tt> method of each component processor,
	 * in the order in which the processors were passed to the constructor.
	 */
	public void process() { 
	    for(AnnotationProcessor ap: aps)
		ap.process();
	}
    }
 

    /**
     *  An annotation processor that does nothing and has no state.
     *  May be used multiple times.
     *
     * @since 1.5
     */
    public final static AnnotationProcessor NO_OP = new NoOpAP();
 
    /**
     * Constructs a new composite annotation processor.  A composite
     * annotation processor combines multiple annotation processors
     * into one and functions by invoking each of its component
     * processors' process methods in sequence.
     *
     * @param aps The processors to create a composite of
     * @since 1.5
     */
    public static AnnotationProcessor getCompositeAnnotationProcessor(AnnotationProcessor... aps) {
	return new CompositeAnnotationProcessor(aps);
    }
 
    /**
     * Constructs a new composite annotation processor.  A composite
     * annotation processor combines multiple annotation processors
     * into one and functions by invoking each of its component
     * processors' process methods in the sequence the processors are
     * returned by the collection's iterator.
     *
     * @param aps A collection of processors to create a composite of
     * @since 1.5
     */
    public static AnnotationProcessor getCompositeAnnotationProcessor(Collection<AnnotationProcessor> aps) {
	return new CompositeAnnotationProcessor(aps);
    }
}