001/* 002 * Copyright (c) 2006-2011 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * All rights reserved. This program and the accompanying materials 005 * are made available under the terms of the Eclipse Public License v1.0 006 * which accompanies this distribution, and is available at 007 * http://www.eclipse.org/legal/epl-v10.html 008 * 009 * Contributors: 010 * bstefanescu 011 */ 012package org.nuxeo.ecm.automation.core.rendering; 013 014import java.io.IOException; 015import java.io.InputStream; 016import java.net.URL; 017import java.util.Collections; 018import java.util.LinkedHashMap; 019import java.util.Map; 020 021import org.mvel2.templates.CompiledTemplate; 022import org.mvel2.templates.TemplateCompiler; 023import org.mvel2.templates.TemplateRuntime; 024import org.nuxeo.common.utils.FileUtils; 025import org.nuxeo.ecm.automation.OperationException; 026import org.nuxeo.runtime.api.Framework; 027import org.nuxeo.runtime.services.resource.ResourceService; 028 029/** 030 * MVEL rendering using a simple cache of compiled template. 031 * 032 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> 033 */ 034public class MvelRender implements Renderer { 035 036 protected Map<String, CompiledTemplate> cache = Collections.synchronizedMap(new Cache()); 037 038 @Override 039 public String render(String uriOrContent, Map<String, Object> root) throws OperationException, IOException { 040 CompiledTemplate compiled = null; 041 String content = null; 042 if (uriOrContent.startsWith(Renderer.TEMPLATE_PREFIX)) { 043 String name = uriOrContent.substring(Renderer.TEMPLATE_PREFIX.length()); 044 compiled = cache.get(name); 045 if (compiled == null) { 046 URL url = Framework.getService(ResourceService.class).getResource(name); 047 if (url == null) { 048 throw new OperationException("Rendering resource not found: " + name); 049 } 050 InputStream in = url.openStream(); 051 try { 052 content = FileUtils.read(in); 053 } finally { 054 in.close(); 055 } 056 compiled = TemplateCompiler.compileTemplate(content); 057 cache.put(name, compiled); 058 } 059 } else { 060 content = uriOrContent; 061 compiled = TemplateCompiler.compileTemplate(content); 062 } 063 064 Object obj = TemplateRuntime.execute(compiled, root); 065 return obj == null ? "" : obj.toString(); 066 } 067 068 @SuppressWarnings("serial") 069 private static class Cache extends LinkedHashMap<String, CompiledTemplate> { 070 071 protected int maxCachedItems; 072 073 private Cache() { 074 this(128); 075 } 076 077 private Cache(int maxCachedItems) { 078 super(maxCachedItems, 1.0f, true); 079 this.maxCachedItems = maxCachedItems; 080 } 081 082 @Override 083 protected boolean removeEldestEntry(Map.Entry<String, CompiledTemplate> eldest) { 084 return size() > maxCachedItems; 085 } 086 087 } 088 089}