001/* 002 * (C) Copyright 2006-2016 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * bstefanescu 018 */ 019package org.nuxeo.ecm.automation.core.rendering; 020 021import java.io.IOException; 022import java.io.InputStream; 023import java.net.URL; 024import java.util.Collections; 025import java.util.LinkedHashMap; 026import java.util.Map; 027 028import org.apache.commons.io.Charsets; 029import org.apache.commons.io.IOUtils; 030import org.mvel2.templates.CompiledTemplate; 031import org.mvel2.templates.TemplateCompiler; 032import org.mvel2.templates.TemplateRuntime; 033import org.nuxeo.ecm.automation.OperationException; 034import org.nuxeo.runtime.api.Framework; 035import org.nuxeo.runtime.services.resource.ResourceService; 036 037/** 038 * MVEL rendering using a simple cache of compiled template. 039 * 040 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> 041 */ 042public class MvelRender implements Renderer { 043 044 protected Map<String, CompiledTemplate> cache = Collections.synchronizedMap(new Cache()); 045 046 @Override 047 public String render(String uriOrContent, Map<String, Object> root) throws OperationException, IOException { 048 CompiledTemplate compiled; 049 String content; 050 if (uriOrContent.startsWith(Renderer.TEMPLATE_PREFIX)) { 051 String name = uriOrContent.substring(Renderer.TEMPLATE_PREFIX.length()); 052 compiled = cache.get(name); 053 if (compiled == null) { 054 URL url = Framework.getService(ResourceService.class).getResource(name); 055 if (url == null) { 056 throw new OperationException("Rendering resource not found: " + name); 057 } 058 try (InputStream in = url.openStream()) { 059 content = IOUtils.toString(in, Charsets.UTF_8); 060 } 061 compiled = TemplateCompiler.compileTemplate(content); 062 cache.put(name, compiled); 063 } 064 } else { 065 content = uriOrContent; 066 compiled = TemplateCompiler.compileTemplate(content); 067 } 068 069 Object obj = TemplateRuntime.execute(compiled, root); 070 return obj == null ? "" : obj.toString(); 071 } 072 073 @SuppressWarnings("serial") 074 private static class Cache extends LinkedHashMap<String, CompiledTemplate> { 075 076 protected int maxCachedItems; 077 078 private Cache() { 079 this(128); 080 } 081 082 private Cache(int maxCachedItems) { 083 super(maxCachedItems, 1.0f, true); 084 this.maxCachedItems = maxCachedItems; 085 } 086 087 @Override 088 protected boolean removeEldestEntry(Map.Entry<String, CompiledTemplate> eldest) { 089 return size() > maxCachedItems; 090 } 091 092 } 093 094}