001 /*
002 GRANITE DATA SERVICES
003 Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005 This file is part of Granite Data Services.
006
007 Granite Data Services is free software; you can redistribute it and/or modify
008 it under the terms of the GNU Library General Public License as published by
009 the Free Software Foundation; either version 2 of the License, or (at your
010 option) any later version.
011
012 Granite Data Services is distributed in the hope that it will be useful, but
013 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015 for more details.
016
017 You should have received a copy of the GNU Library General Public License
018 along with this library; if not, see <http://www.gnu.org/licenses/>.
019 */
020
021 package org.granite.config;
022
023 import java.io.Externalizable;
024 import java.io.IOException;
025 import java.io.ObjectInput;
026 import java.io.ObjectOutput;
027 import java.lang.reflect.InvocationTargetException;
028 import java.util.List;
029 import java.util.concurrent.ConcurrentHashMap;
030
031 import org.granite.messaging.amf.io.util.Property;
032 import org.granite.messaging.amf.io.util.externalizer.Externalizer;
033 import org.granite.messaging.amf.io.util.externalizer.annotation.ExternalizedBean;
034 import org.granite.util.ClassUtil;
035 import org.granite.util.XMap;
036
037 /**
038 * @author Franck WOLFF
039 */
040 public class ExternalizerFactory implements ConfigurableFactory<Externalizer> {
041
042 private static final Externalizer NULL_EXTERNALIZER = new Externalizer() {
043
044 private final static String NOT_IMPLEMENTED = "Not implemented (null externalizer)";
045
046 public void configure(XMap properties) {
047 throw new RuntimeException(NOT_IMPLEMENTED);
048 }
049 public List<Property> findOrderedFields(Class<?> clazz) {
050 throw new RuntimeException(NOT_IMPLEMENTED);
051 }
052 public Object newInstance(String type, ObjectInput in)
053 throws IOException, ClassNotFoundException, InstantiationException,
054 InvocationTargetException, IllegalAccessException {
055 throw new RuntimeException(NOT_IMPLEMENTED);
056 }
057 public void readExternal(Object o, ObjectInput in)
058 throws IOException, ClassNotFoundException, IllegalAccessException {
059 throw new RuntimeException(NOT_IMPLEMENTED);
060 }
061 public void writeExternal(Object o, ObjectOutput out)
062 throws IOException, IllegalAccessException {
063 throw new RuntimeException(NOT_IMPLEMENTED);
064 }
065 public int accept(Class<?> clazz) {
066 return -1;
067 }
068 };
069
070 private final ConcurrentHashMap<String, Externalizer> externalizersCache = new ConcurrentHashMap<String, Externalizer>();
071
072 public Externalizer getNullInstance() {
073 return NULL_EXTERNALIZER;
074 }
075
076 public Externalizer getInstance(String type, GraniteConfig config) throws GraniteConfigException {
077 return newInstance(type, config);
078 }
079
080 public Externalizer getInstanceForBean(
081 List<Externalizer> scannedConfigurables,
082 Class<?> beanClass,
083 GraniteConfig config) throws GraniteConfigException {
084
085 Externalizer externalizer = NULL_EXTERNALIZER;
086
087 if (!Externalizable.class.isAssignableFrom(beanClass)) {
088 ExternalizedBean annotation = beanClass.getAnnotation(ExternalizedBean.class);
089
090 Class<? extends Externalizer> type = null;
091 if (annotation != null && annotation.type() != null)
092 type = annotation.type();
093 else {
094 int maxWeight = -1;
095 for (Externalizer e : scannedConfigurables) {
096 int weight = e.accept(beanClass);
097 if (weight > maxWeight) {
098 maxWeight = weight;
099 type = e.getClass();
100 }
101 }
102 }
103
104 if (type != null)
105 externalizer = newInstance(type.getName(), config);
106 }
107
108 return externalizer;
109 }
110
111 private Externalizer newInstance(String externalizerType, GraniteConfig config) {
112 Externalizer externalizer = externalizersCache.get(externalizerType);
113 if (externalizer == null) {
114 try {
115 externalizer = ClassUtil.newInstance(externalizerType, Externalizer.class);
116 } catch (Exception e) {
117 throw new GraniteConfigException("Could not instantiate externalizer: " + externalizerType, e);
118 }
119 Externalizer previous = externalizersCache.putIfAbsent(externalizerType, externalizer);
120 if (previous != null)
121 externalizer = previous;
122 else
123 externalizer.configure(config.getExternalizersConfiguration());
124 }
125 return externalizer;
126 }
127 }