/*
* Copyright 2011 JBoss, by Red Hat, 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 org.jboss.errai.marshalling.client;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import org.jboss.errai.common.client.protocols.SerializationParts;
import org.jboss.errai.marshalling.client.api.Marshaller;
import org.jboss.errai.marshalling.client.api.MarshallingSession;
import org.jboss.errai.marshalling.client.api.ParserFactory;
import org.jboss.errai.marshalling.client.api.json.EJValue;
import org.jboss.errai.marshalling.client.marshallers.ListMarshaller;
import org.jboss.errai.marshalling.client.marshallers.MapMarshaller;
import org.jboss.errai.marshalling.client.util.MarshallUtil;
import org.jboss.errai.marshalling.client.util.NumbersUtils;
/**
* A collection of static methods for accomplishing common tasks with the Errai
* marshalling API.
*
* @author Mike Brock
* @author Jonathan Fuerth <jfuerth@redhat.com>
* @author Christian Sadilek <csadilek@redhat.com>
*/
public abstract class Marshalling {
/**
* Returns true if the given type is marshallable by the Errai Marshalling
* system, and false otherwise.
* <p>
* Marshallable types include all native Java types, most built-in Java API
* types, types annotated with {@code @Portable}, types configured for
* marshalling via {@code ErraiApp.properties}, and arrays, Collections, and
* Maps of marshallable types.
*
* @param type
* The type to check for marshallability.
* @return True for marshallable types and false for non-marshallable types.
*/
public static boolean canHandle(final Class<?> type) {
return MarshallingSessionProviderFactory.getProvider().hasMarshaller(type.getName());
}
/**
* Returns a JSON representation of the given object, recursively including
* all of its nested attributes.
*
* @param obj
* The object to marshall. Should be of a type for which
* {@link #canHandle(Class)} returns true. Null is permitted.
* @return The JSON representation of the given object and all nested
* properties reachable from it.
*/
public static String toJSON(final Object obj) {
if (obj == null) {
return "{\"" + SerializationParts.ENCODED_TYPE + "\":\"java.lang.Object\",\""
+ SerializationParts.QUALIFIED_VALUE + "\":null}";
}
final MarshallingSession session = MarshallingSessionProviderFactory.getEncoding();
if (needsQualification(obj)) {
return NumbersUtils.qualifiedNumericEncoding(obj);
}
else {
return MarshallUtil.getMarshaller(obj, session).marshall(obj, session);
}
}
/**
* Appends a JSON representation of the given object to the given Appendable,
* recursively including all of its nested attributes.
*
* @param appendTo
* the Appendable to write the JSON representation to.
* @param obj
* The object to marshall. Should be of a type for which
* {@link #canHandle(Class)} returns true. Null is permitted.
*
*/
public static void toJSON(final Appendable appendTo, final Object obj) throws IOException {
appendTo.append(toJSON(obj));
}
/**
* Works the same as a call to {@link #toJSON(Object)}, but may perform better.
*
* @param obj The map to marshal to JSON.
* @return The JSON representation of the map.
*/
@SuppressWarnings("unchecked")
public static String toJSON(final Map<Object, Object> obj) {
return MapMarshaller.INSTANCE.marshall(obj, MarshallingSessionProviderFactory.getEncoding());
}
/**
* Works the same as a call to {@link #toJSON(Object)}, but may perform better.
*
* @param arr The list to marshal to JSON.
* @return The JSON representation of the list.
*/
public static String toJSON(final List arr) {
return ListMarshaller.INSTANCE.marshall(arr, MarshallingSessionProviderFactory.getEncoding());
}
/**
* Converts the given JSON message to a Java object, recursively decoding
* nested attributes contained in that message.
*
* @param json
* The JSON representation of the object graph to demarshall.
* @param type
* The expected type of the root of the object graph.
* @return the root of the reconstructed object graph.
*/
public static <T> T fromJSON(final String json, final Class<T> type) {
return fromJSON(json, type, null);
}
/**
* Converts the given JSON message (which is likely a collection) to a Java
* object, recursively decoding nested attributes contained in that message.
*
* @param json
* The JSON representation of the object graph to demarshall.
* @param type
* The expected type of the root of the object graph.
* @param assumedElementType
* the type of elements assumed to be in the root collection. A null
* value means that either the root object is not a collection, or
* its element type is provided in the JSON message.
* @return the root of the reconstructed object graph.
*/
@SuppressWarnings("unchecked")
public static <T> T fromJSON(final String json, final Class<T> type, final Class<?> assumedElementType) {
final EJValue parsedValue = ParserFactory.get().parse(json);
final MarshallingSession session = MarshallingSessionProviderFactory.getDecoding();
if (assumedElementType != null) {
session.setAssumedElementType(assumedElementType.getName());
}
final Marshaller<Object> marshallerInstance = session.getMarshallerInstance(type.getName());
return (T) marshallerInstance.demarshall(parsedValue, session);
}
/**
* Converts the given JSON message to a Java object, recursively decoding
* nested attributes contained in that message, which must contain type
* information for the root object.
*
* @param json
* The JSON representation of the object graph to demarshall.
* @return the root of the reconstructed object graph.
*/
public static Object fromJSON(final String json) {
return fromJSON(json, Object.class);
}
public static boolean needsQualification(final Object o) {
return (o instanceof Number && o.getClass().getName().startsWith("java.lang.")
&& !(o instanceof Long))
|| o instanceof Boolean
|| o instanceof Character;
}
}