AbstractImageSource.java

/*
 * Copyright (c) 2008, Harald Kuhr
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name "TwelveMonkeys" nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.twelvemonkeys.image;

import java.awt.image.ImageProducer;
import java.awt.image.ImageConsumer;
import java.util.List;
import java.util.ArrayList;

/**
 * AbstractImageSource
 * <p/>
 *
 * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
 * @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/image/AbstractImageSource.java#1 $
 */
public abstract class AbstractImageSource implements ImageProducer {
    private List<ImageConsumer> consumers = new ArrayList<ImageConsumer>();
    protected int width;
    protected int height;
    protected int xOff;
    protected int yOff;

    // ImageProducer interface
    public void addConsumer(final ImageConsumer pConsumer) {
        if (consumers.contains(pConsumer)) {
            return;
        }

        consumers.add(pConsumer);

        try {
            initConsumer(pConsumer);
            sendPixels(pConsumer);

            if (isConsumer(pConsumer)) {
                pConsumer.imageComplete(ImageConsumer.STATICIMAGEDONE);

                // Get rid of "sticky" consumers...
                if (isConsumer(pConsumer)) {
                    pConsumer.imageComplete(ImageConsumer.IMAGEERROR);
                    removeConsumer(pConsumer);
                }
            }
        }
        catch (Exception e) {
            e.printStackTrace();

            if (isConsumer(pConsumer)) {
                pConsumer.imageComplete(ImageConsumer.IMAGEERROR);
            }
        }
    }

    public void removeConsumer(final ImageConsumer pConsumer) {
        consumers.remove(pConsumer);
    }

    /**
     * This implementation silently ignores this instruction. If pixel data is
     * not in TDLR order by default, subclasses must override this method.
     *
     * @param pConsumer the consumer that requested the resend
     *
     * @see ImageProducer#requestTopDownLeftRightResend(java.awt.image.ImageConsumer)
     */
    public void requestTopDownLeftRightResend(final ImageConsumer pConsumer) {
        // ignore
    }

    public void startProduction(final ImageConsumer pConsumer) {
        addConsumer(pConsumer);
    }

    public boolean isConsumer(final ImageConsumer pConsumer) {
        return consumers.contains(pConsumer);
    }

    protected abstract void initConsumer(ImageConsumer pConsumer);

    protected abstract void sendPixels(ImageConsumer pConsumer);
}