001/* 002 * (C) Copyright 2006-2010 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.io.services.codec; 020 021import java.io.IOException; 022import java.lang.reflect.ParameterizedType; 023import java.lang.reflect.Type; 024 025import org.codehaus.jackson.JsonGenerator; 026import org.codehaus.jackson.JsonParser; 027import org.codehaus.jackson.map.ObjectMapper; 028import org.nuxeo.ecm.core.api.CoreSession; 029 030/** 031 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> 032 */ 033public abstract class ObjectCodec<T> { 034 035 public static Class<?> findParametrizedType(Class<?> clazz) { 036 Type superclass = clazz.getGenericSuperclass(); 037 while (superclass instanceof Class<?>) { 038 superclass = ((Class<?>) superclass).getGenericSuperclass(); 039 } 040 if (superclass == null) { 041 throw new RuntimeException("Missing type parameter."); 042 } 043 Type type = ((ParameterizedType) superclass).getActualTypeArguments()[0]; 044 if (!(type instanceof Class<?>)) { 045 throw new RuntimeException("Invalid class parameter type. " + type); 046 } 047 return (Class<?>) type; 048 } 049 050 protected Class<T> type; 051 052 @SuppressWarnings("unchecked") 053 public ObjectCodec() { 054 this.type = (Class<T>) findParametrizedType(getClass()); 055 } 056 057 public ObjectCodec(Class<T> type) { 058 this.type = type; 059 } 060 061 /** 062 * Get this codec type. Implementors can override to return a short name. The default name is the object type name. 063 * 064 * @return 065 */ 066 public String getType() { 067 return type.getName(); 068 } 069 070 /** 071 * Whether this codec is a builtin codec 072 * 073 * @return 074 */ 075 public boolean isBuiltin() { 076 return false; 077 } 078 079 public Class<T> getJavaType() { 080 return type; 081 } 082 083 public void write(JsonGenerator jg, T value) throws IOException { 084 if (jg.getCodec() == null) { 085 jg.setCodec(new ObjectMapper()); 086 } 087 jg.writeObject(value); 088 } 089 090 /** 091 * When the object codec is called the stream is positioned on the first value. For inlined objects this is the 092 * first value after the "entity-type" property. For non inlined objects this will be the object itself (i.e. '{' or 093 * '[') 094 * 095 * @param jp 096 * @return 097 * @throws IOException 098 */ 099 public T read(JsonParser jp, CoreSession session) throws IOException { 100 if (jp.getCodec() == null) { 101 jp.setCodec(new ObjectMapper()); 102 } 103 return jp.readValueAs(type); 104 } 105 106}