/***
* Copyright (c) 2009 Caelum - www.caelum.com.br/opensource All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package br.com.caelum.vraptor.serialization.gson;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.IOException;
import java.io.Writer;
import java.util.Calendar;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import br.com.caelum.vraptor.interceptor.TypeNameExtractor;
import br.com.caelum.vraptor.serialization.ProxyInitializer;
import br.com.caelum.vraptor.serialization.Serializer;
import br.com.caelum.vraptor.serialization.SerializerBuilder;
import br.com.caelum.vraptor.serialization.xstream.Serializee;
import com.google.gson.Gson;
/**
* A SerializerBuilder based on Gson
*
* @author Renan Reis
* @author Guilherme Mangabeira
*/
public class GsonSerializer implements SerializerBuilder {
private final Writer writer;
private final TypeNameExtractor extractor;
private final ProxyInitializer initializer;
private final Serializee serializee;
protected VRaptorGsonBuilder builder;
public GsonSerializer(VRaptorGsonBuilder builder, Writer writer, TypeNameExtractor extractor,
ProxyInitializer initializer, Serializee serializee) {
this.writer = writer;
this.extractor = extractor;
this.initializer = initializer;
this.builder = builder;
this.serializee = serializee;
}
public Serializer exclude(String... names) {
serializee.excludeAll(names);
return this;
}
public Serializer excludeAll() {
serializee.excludeAll();
return this;
}
private void preConfigure(Object obj, String alias) {
checkNotNull(obj, "You can't serialize null objects");
serializee.setRootClass(initializer.getActualClass(obj));
if (alias == null) {
if (Collection.class.isInstance(obj) && (List.class.isInstance(obj))) {
alias = "list";
} else {
alias = extractor.nameFor(serializee.getRootClass());
}
}
builder.setAlias(alias);
setRoot(obj);
}
private void setRoot(Object obj) {
if (Collection.class.isInstance(obj)) {
this.serializee.setRoot(normalizeList(obj));
} else {
this.serializee.setRoot(obj);
}
}
@SuppressWarnings("unchecked")
private Collection<Object> normalizeList(Object obj) {
Collection<Object> list;
list = (Collection<Object>) obj;
serializee.setElementTypes(findElementTypes(list));
return list;
}
public <T> Serializer from(T object, String alias) {
preConfigure(object, alias);
return this;
}
public <T> Serializer from(T object) {
preConfigure(object, null);
return this;
}
private Set<Class<?>> findElementTypes(Collection<Object> list) {
Set<Class<?>> set = new HashSet<Class<?>>();
for (Object element : list) {
if (element != null && !isPrimitive(element.getClass())) {
set.add(initializer.getActualClass(element));
}
}
return set;
}
public Serializer include(String... fields) {
serializee.includeAll(fields);
return this;
}
public void serialize() {
try {
Object root = serializee.getRoot();
builder.setExclusionStrategies(new Exclusions(serializee));
Gson gson = builder.create();
String alias = builder.getAlias();
if (builder.isWithoutRoot()) {
writer.write(gson.toJson(root));
} else {
Map<String, Object> tree = new HashMap<String, Object>();
tree.put(alias, root);
writer.write(gson.toJson(tree));
}
} catch (IOException e) {
throw new RuntimeException("Não pode serializar", e);
}
}
public Serializer recursive() {
this.serializee.setRecursive(true);
return this;
}
protected static boolean isPrimitive(Class<?> type) {
return type.isPrimitive() || type.isEnum() || Number.class.isAssignableFrom(type) || type.equals(String.class)
|| Date.class.isAssignableFrom(type) || Calendar.class.isAssignableFrom(type)
|| Boolean.class.equals(type) || Character.class.equals(type);
}
}