AbstractChainingPrintRenderer.java

/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.rendering.renderer;

import java.util.ArrayDeque;
import java.util.Deque;

import org.xwiki.rendering.listener.chaining.AbstractChainingListener;
import org.xwiki.rendering.listener.chaining.ChainingListener;
import org.xwiki.rendering.renderer.printer.WikiPrinter;

/**
 * @version $Id: 93cde196e285213ec5d9e15d0478005adf47e2a6 $
 * @since 1.8RC1
 */
public abstract class AbstractChainingPrintRenderer extends AbstractChainingListener implements PrintRenderer
{
    /**
     * The printer stack. Can be used to print in a specific printer and then easily return to the previous one.
     */
    private Deque<WikiPrinter> printers = new ArrayDeque<WikiPrinter>();

    /**
     * @return the main printer.
     */
    public WikiPrinter getMainPrinter()
    {
        return this.printers.getLast();
    }

    @Override
    public WikiPrinter getPrinter()
    {
        return this.printers.peek();
    }

    /**
     * {@inheritDoc}
     *
     * @since 2.0M3
     */
    @Override
    public void setPrinter(WikiPrinter printer)
    {
        pushPrinter(printer);
    }

    /**
     * Change the current {@link WikiPrinter} with the provided one.
     *
     * @param wikiPrinter the new {@link WikiPrinter} to use
     */
    protected void pushPrinter(WikiPrinter wikiPrinter)
    {
        this.printers.push(wikiPrinter);

        // Since we're setting a new printer to use, make sure that all print renderers in the chain have the new
        // printer set. Only do this if we're on the top level Print Renderer.
        if (getListenerChain().indexOf(getClass()) == 0) {
            ChainingListener nextListener = this;
            while ((nextListener = getListenerChain().getNextListener(nextListener.getClass())) != null) {
                if (PrintRenderer.class.isAssignableFrom(nextListener.getClass())) {
                    ((PrintRenderer) nextListener).setPrinter(wikiPrinter);
                }
            }
        }
    }

    /**
     * Removes the current {@link WikiPrinter} and instead sets the previous printer as active.
     */
    protected void popPrinter()
    {
        this.printers.pop();
    }
}