/*
* Copyright 2010 Google Inc.
*
* 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 com.google.gwt.requestfactory.shared.impl;
import com.google.gwt.autobean.shared.AutoBean;
import com.google.gwt.autobean.shared.AutoBeanUtils;
import com.google.gwt.autobean.shared.Splittable;
import com.google.gwt.autobean.shared.ValueCodex;
import com.google.gwt.autobean.shared.impl.LazySplittable;
import com.google.gwt.autobean.shared.impl.StringQuoter;
import com.google.gwt.requestfactory.shared.BaseProxy;
import com.google.gwt.requestfactory.shared.EntityProxyId;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* Analogous to {@link ValueCodex}, but for object types.
*/
public class EntityCodex {
/**
* Abstracts the process by which EntityProxies are created.
*/
public interface EntitySource {
/**
* Expects an encoded
* {@link com.google.gwt.requestfactory.shared.messages.IdMessage}.
*/
<Q extends BaseProxy> AutoBean<Q> getBeanForPayload(
Splittable serializedIdMessage);
/**
* Should return an encoded
* {@link com.google.gwt.requestfactory.shared.messages.IdMessage}.
*/
Splittable getSerializedProxyId(SimpleProxyId<?> stableId);
boolean isEntityType(Class<?> clazz);
boolean isValueType(Class<?> clazz);
}
/**
* Collection support is limited to value types and resolving ids.
*/
public static Object decode(EntitySource source, Class<?> type,
Class<?> elementType, Splittable split) {
if (split == null || split == LazySplittable.NULL) {
return null;
}
// Collection support
if (elementType != null) {
Collection<Object> collection = null;
if (List.class.equals(type)) {
collection = new ArrayList<Object>();
} else if (Set.class.equals(type)) {
collection = new HashSet<Object>();
} else {
throw new UnsupportedOperationException();
}
// Decode values
if (ValueCodex.canDecode(elementType)) {
for (int i = 0, j = split.size(); i < j; i++) {
if (split.isNull(i)) {
collection.add(null);
} else {
Object element = ValueCodex.decode(elementType, split.get(i));
collection.add(element);
}
}
} else {
for (int i = 0, j = split.size(); i < j; i++) {
if (split.isNull(i)) {
collection.add(null);
} else {
Object element = decode(source, elementType, null, split.get(i));
collection.add(element);
}
}
}
return collection;
}
if (source.isEntityType(type) || source.isValueType(type)
|| EntityProxyId.class.equals(type)) {
return source.getBeanForPayload(split).as();
}
// Fall back to values
return ValueCodex.decode(type, split);
}
/**
* Collection support is limited to value types and resolving ids.
*/
public static Object decode(EntitySource source, Class<?> type,
Class<?> elementType, String jsonPayload) {
Splittable split = StringQuoter.split(jsonPayload);
return decode(source, type, elementType, split);
}
/**
* Create a wire-format representation of an object.
*/
public static Splittable encode(EntitySource source, Object value) {
if (value == null) {
return LazySplittable.NULL;
}
if (value instanceof Poser<?>) {
value = ((Poser<?>) value).getPosedValue();
}
if (value instanceof Iterable<?>) {
StringBuffer toReturn = new StringBuffer();
toReturn.append('[');
boolean first = true;
for (Object val : ((Iterable<?>) value)) {
if (!first) {
toReturn.append(',');
} else {
first = false;
}
if (val == null) {
toReturn.append("null");
} else {
toReturn.append(encode(source, val).getPayload());
}
}
toReturn.append(']');
return new LazySplittable(toReturn.toString());
}
if (value instanceof BaseProxy) {
AutoBean<BaseProxy> autoBean = AutoBeanUtils.getAutoBean((BaseProxy) value);
value = BaseProxyCategory.stableId(autoBean);
}
if (value instanceof SimpleProxyId<?>) {
return source.getSerializedProxyId((SimpleProxyId<?>) value);
}
return ValueCodex.encode(value);
}
}