001/* 002 * (C) Copyright 2006-2010 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 * 014 * Contributors: 015 * bstefanescu 016 */ 017package org.nuxeo.ecm.automation.io.services.codec; 018 019import java.io.IOException; 020import java.lang.reflect.ParameterizedType; 021import java.lang.reflect.Type; 022 023import org.codehaus.jackson.JsonGenerator; 024import org.codehaus.jackson.JsonParser; 025import org.codehaus.jackson.map.ObjectMapper; 026import org.nuxeo.ecm.core.api.CoreSession; 027 028/** 029 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> 030 */ 031public abstract class ObjectCodec<T> { 032 033 public static Class<?> findParametrizedType(Class<?> clazz) { 034 Type superclass = clazz.getGenericSuperclass(); 035 while (superclass instanceof Class<?>) { 036 superclass = ((Class<?>) superclass).getGenericSuperclass(); 037 } 038 if (superclass == null) { 039 throw new RuntimeException("Missing type parameter."); 040 } 041 Type type = ((ParameterizedType) superclass).getActualTypeArguments()[0]; 042 if (!(type instanceof Class<?>)) { 043 throw new RuntimeException("Invalid class parameter type. " + type); 044 } 045 return (Class<?>) type; 046 } 047 048 protected Class<T> type; 049 050 @SuppressWarnings("unchecked") 051 public ObjectCodec() { 052 this.type = (Class<T>) findParametrizedType(getClass()); 053 } 054 055 public ObjectCodec(Class<T> type) { 056 this.type = type; 057 } 058 059 /** 060 * Get this codec type. Implementors can override to return a short name. The default name is the object type name. 061 * 062 * @return 063 */ 064 public String getType() { 065 return type.getName(); 066 } 067 068 /** 069 * Whether this codec is a builtin codec 070 * 071 * @return 072 */ 073 public boolean isBuiltin() { 074 return false; 075 } 076 077 public Class<T> getJavaType() { 078 return type; 079 } 080 081 public void write(JsonGenerator jg, T value) throws IOException { 082 if (jg.getCodec() == null) { 083 jg.setCodec(new ObjectMapper()); 084 } 085 jg.writeObject(value); 086 } 087 088 /** 089 * When the object codec is called the stream is positioned on the first value. For inlined objects this is the 090 * first value after the "entity-type" property. For non inlined objects this will be the object itself (i.e. '{' or 091 * '[') 092 * 093 * @param jp 094 * @return 095 * @throws IOException 096 */ 097 public T read(JsonParser jp, CoreSession session) throws IOException { 098 if (jp.getCodec() == null) { 099 jp.setCodec(new ObjectMapper()); 100 } 101 return jp.readValueAs(type); 102 } 103 104}