001/*
002 * (C) Copyright 2010 Nuxeo SAS (http://nuxeo.com/) and contributors.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the GNU Lesser General Public License
006 * (LGPL) version 2.1 which accompanies this distribution, and is available at
007 * http://www.gnu.org/licenses/lgpl.html
008 *
009 * This library is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 * Contributors:
014 * Nuxeo - initial API and implementation
015 */
016
017package org.nuxeo.ecm.platform.rendition.impl;
018
019import java.util.List;
020
021import org.nuxeo.ecm.core.api.Blob;
022import org.nuxeo.ecm.platform.rendition.Rendition;
023import org.nuxeo.ecm.platform.rendition.service.RenditionDefinition;
024
025/**
026 * Implementation of the {@link Rendition} interface that allows lazy computation of the rendition Blobs
027 *
028 * @author <a href="mailto:tdelprat@nuxeo.com">Tiry</a>
029 */
030public abstract class LazyRendition extends AbstractRendition implements Rendition {
031
032    protected List<Blob> blobs = null;
033
034    public LazyRendition(RenditionDefinition definition) {
035        super(definition);
036    }
037
038    public Blob getBlob() {
039        List<Blob> blobs = getBlobs();
040        if (blobs != null && blobs.size() > 0) {
041            return blobs.get(0);
042        }
043        return null;
044    }
045
046    @Override
047    public List<Blob> getBlobs() {
048        if (blobs == null) {
049            blobs = computeRenditionBlobs();
050        }
051        return blobs;
052    }
053
054    protected abstract List<Blob> computeRenditionBlobs();
055
056}