Gson extension

modules/org.restlet.ext.gson/META-INF/MANIFEST.MF

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+Manifest-Version: 1.0
+Bundle-ManifestVersion: 2
+Bundle-Name: Restlet Extension - Gson
+Bundle-SymbolicName: org.restlet.ext.gson
+Bundle-Version: 2.2
+Bundle-Vendor: Restlet S.A.S.
+Export-Package: org.restlet.ext.gson
+Import-Package: 
+ org.restlet,
+ org.restlet.data,
+ org.restlet.engine,
+ org.restlet.engine.converter,
+ org.restlet.engine.resource,
+ org.restlet.representation,
+ org.restlet.resource,
+ org.restlet.service,
+ org.restlet.util
+Bundle-RequiredExecutionEnvironment: JavaSE-1.6

modules/org.restlet.ext.gson/build.properties

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+source.. = src/
+output.. = bin/
+bin.includes = META-INF/,\
+               .

modules/org.restlet.ext.gson/module.xml

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+<module id="gson" excludes="gwt" type="integration" package="org.restlet.ext.gson">
+	<name>Restlet Extension - Gson</name>
+	<description>Integration with Gson.</description>
+	<distributions>
+		<distribution id="classic" />
+		<distribution id="maven" />
+		<distribution id="p2" />
+	</distributions>
+
+	<dependencies>
+		<dependency type="library" id="gson" primary="true" />
+		<dependency type="module" id="core" />
+	</dependencies>
+	<wikiUri>299-restlet</wikiUri>
+</module>

modules/org.restlet.ext.gson/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.restlet.dev</groupId>
+		<artifactId>org.restlet.parent</artifactId>
+		<version>2.2-SNAPSHOT</version>
+	</parent>
+
+	<artifactId>org.restlet.ext.gson</artifactId>
+	<name>Restlet Extension - Gson</name>
+	<description>Integration with Gson.</description>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.restlet.dev</groupId>
+			<artifactId>org.restlet</artifactId>
+<!--			<version>2.2-SNAPSHOT</version> -->
+			<version>${version}</version>
+
+		</dependency>
+		<dependency>
+			<groupId>com.google.code.gson</groupId>
+			<artifactId>gson</artifactId>
+			<version>2.2</version>
+		</dependency>
+		<dependency>
+			<groupId>joda-time</groupId>
+			<artifactId>joda-time</artifactId>
+			<version>2.1</version>
+		</dependency>
+	</dependencies>
+</project>

modules/org.restlet.ext.gson/src/META-INF/services/org.restlet.engine.converter.ConverterHelper

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+org.restlet.ext.gson.GsonConverter

modules/org.restlet.ext.gson/src/org/restlet/ext/gson/GsonConverter.java

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+package org.restlet.ext.gson;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.restlet.data.MediaType;
+import org.restlet.data.Preference;
+import org.restlet.engine.converter.ConverterHelper;
+import org.restlet.engine.resource.VariantInfo;
+import org.restlet.representation.Representation;
+import org.restlet.representation.Variant;
+import org.restlet.resource.Resource;
+
+/**
+ * Inspired from Jackson extension of Restlet
+ * 
+ * @author nealmi 
+ *  
+ *         Copyright 2012 Neal Mi
+ * 
+ *         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.
+ */
+public class GsonConverter extends ConverterHelper {
+    private static final VariantInfo VARIANT_JSON = new VariantInfo(MediaType.APPLICATION_JSON);
+
+    protected <T> GsonRepresentation<T> create(Representation source, Class<T> objectClass) {
+        return new GsonRepresentation<T>(source, objectClass);
+    }
+
+    protected <T> GsonRepresentation<T> create(MediaType mediaType, T source) {
+        return new GsonRepresentation<T>(mediaType, source);
+    }
+
+    @Override
+    public List<Class<?>> getObjectClasses(Variant source) {
+        List<Class<?>> result = null;
+
+        if (VARIANT_JSON.isCompatible(source)) {
+            result = addObjectClass(result, Object.class);
+            result = addObjectClass(result, GsonRepresentation.class);
+        }
+
+        return result;
+    }
+
+    @Override
+    public List<VariantInfo> getVariants(Class<?> source) {
+        List<VariantInfo> result = null;
+
+        if (source != null) {
+            result = addVariant(result, VARIANT_JSON);
+        }
+
+        return result;
+    }
+
+    @Override
+    public float score(Object source, Variant target, Resource resource) {
+        float result = -1.0F;
+
+        if (source instanceof GsonRepresentation<?>) {
+            result = 1.0F;
+        } else {
+            if (target == null) {
+                result = 0.5F;
+            } else if (VARIANT_JSON.isCompatible(target)) {
+                result = 0.8F;
+            } else {
+                result = 0.5F;
+            }
+        }
+
+        return result;
+    }
+
+    @Override
+    public <T> float score(Representation source, Class<T> target, Resource resource) {
+        float result = -1.0F;
+
+        if (source instanceof GsonRepresentation<?>) {
+            result = 1.0F;
+        } else if ((target != null) && GsonRepresentation.class.isAssignableFrom(target)) {
+            result = 1.0F;
+        } else if (VARIANT_JSON.isCompatible(source)) {
+            result = 0.8F;
+        }
+
+        return result;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T toObject(Representation source, Class<T> target, Resource resource) throws IOException {
+        Object result = null;
+
+        // The source for the gson conversion
+        GsonRepresentation<?> gsonSource = null;
+
+        if (source instanceof GsonRepresentation) {
+            gsonSource = (GsonRepresentation<?>) source;
+        } else if (VARIANT_JSON.isCompatible(source)) {
+            gsonSource = create(source, target);
+        }
+
+        if (gsonSource != null) {
+            // Handle the conversion
+            if ((target != null) && GsonRepresentation.class.isAssignableFrom(target)) {
+                result = gsonSource;
+            } else {
+                result = gsonSource.getObject();
+            }
+        }
+
+        return (T) result;
+    }
+
+    @Override
+    public Representation toRepresentation(Object source, Variant target, Resource resource) throws IOException {
+        Representation result = null;
+
+        if (source instanceof GsonRepresentation) {
+            result = (GsonRepresentation<?>) source;
+        } else {
+            if (target.getMediaType() == null) {
+                target.setMediaType(MediaType.APPLICATION_JSON);
+            }
+
+            if (VARIANT_JSON.isCompatible(target)) {
+                GsonRepresentation<Object> gsonRepresentation = create(target.getMediaType(), source);
+                result = gsonRepresentation;
+            }
+        }
+
+        return result;
+    }
+
+    @Override
+    public <T> void updatePreferences(List<Preference<MediaType>> preferences, Class<T> entity) {
+        updatePreferences(preferences, MediaType.APPLICATION_JSON, 1.0F);
+    }
+
+}

modules/org.restlet.ext.gson/src/org/restlet/ext/gson/GsonRepresentation.java

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+package org.restlet.ext.gson;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.lang.reflect.Type;
+import java.text.DateFormat;
+import java.util.Date;
+
+import org.joda.time.DateTime;
+import org.restlet.data.MediaType;
+import org.restlet.representation.Representation;
+import org.restlet.representation.WriterRepresentation;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+import com.google.gson.JsonSerializationContext;
+import com.google.gson.JsonSerializer;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+
+/**
+ * Inspired from Jackson extension of Restlet
+ * 
+ * @author nealmi
+ * 
+ * @param <T>
+ * 
+ *            Copyright 2012 Neal Mi
+ * 
+ *            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.
+ */
+public class GsonRepresentation<T> extends WriterRepresentation {
+    /** The (parsed) object to format. */
+    private T object;
+
+    /** The object class to instantiate. */
+    private Class<T> objectClass;
+
+    /** The JSON representation to parse. */
+    private Representation jsonRepresentation;
+
+    /** The modifiable Gson builder. */
+    private GsonBuilder builder;
+
+    public GsonRepresentation(MediaType mediaType) {
+        super(mediaType);
+    }
+
+    @SuppressWarnings("unchecked")
+    public GsonRepresentation(T object) {
+        super(MediaType.APPLICATION_JSON);
+        this.object = object;
+        this.objectClass = ((Class<T>) ((object == null) ? null : object.getClass()));
+        this.jsonRepresentation = null;
+        this.builder = null;
+    }
+
+    public GsonRepresentation(Representation representation, Class<T> objectClass) {
+        super(representation.getMediaType());
+        this.object = null;
+        this.objectClass = objectClass;
+        this.jsonRepresentation = representation;
+        this.builder = null;
+    }
+
+    @SuppressWarnings("unchecked")
+    public GsonRepresentation(MediaType mediaType, T object) {
+        super(mediaType);
+        this.object = object;
+        this.objectClass = ((Class<T>) ((object == null) ? null : object.getClass()));
+        this.jsonRepresentation = null;
+        this.builder = null;
+    }
+
+    @Override
+    public void write(Writer writer) throws IOException {
+        if (jsonRepresentation != null) {
+            jsonRepresentation.write(writer);
+        } else {
+            Gson gson = getBuilder().create();
+            gson.toJson(object, objectClass, new JsonWriter(writer));
+        }
+    }
+
+    public T getObject() throws IOException {
+        T result = null;
+
+        if (this.object != null) {
+            result = this.object;
+        } else if (this.jsonRepresentation != null) {
+            Gson gson = getBuilder().create();
+            result = gson.fromJson(new JsonReader(jsonRepresentation.getReader()), this.objectClass);
+        }
+
+        return result;
+    }
+
+    public void setObject(T object) {
+        this.object = object;
+    }
+
+    public Class<T> getObjectClass() {
+        return objectClass;
+    }
+
+    public void setObjectClass(Class<T> objectClass) {
+        this.objectClass = objectClass;
+    }
+
+    public Representation getJsonRepresentation() {
+        return jsonRepresentation;
+    }
+
+    public void setJsonRepresentation(Representation jsonRepresentation) {
+        this.jsonRepresentation = jsonRepresentation;
+    }
+
+    private class ISODateSerializer implements JsonSerializer<Date> {
+        public JsonElement serialize(Date src, Type typeOfSrc, JsonSerializationContext context) {
+            DateTime dt = new DateTime(src);
+            // DateTime dtz = dt.withZone(DateTimeZone.forOffsetHours(-8));
+            return new JsonPrimitive(dt.toString());
+        }
+    }
+
+    private class ISODateDeserializer implements JsonDeserializer<Date> {
+        public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+                throws JsonParseException {
+            return new DateTime(json.getAsJsonPrimitive().getAsString()).toDate();
+        }
+    }
+
+    public GsonBuilder getBuilder() {
+        if (builder == null) {
+            builder = createBuilder().registerTypeAdapter(Date.class, new ISODateSerializer()).registerTypeAdapter(
+                    Date.class, new ISODateDeserializer());
+        }
+        return builder;
+    }
+
+    private GsonBuilder createBuilder() {
+        GsonBuilder gsonBuilder = new GsonBuilder();
+        gsonBuilder.setDateFormat(DateFormat.FULL);
+        return gsonBuilder;
+    }
+
+    public void setBuilder(GsonBuilder builder) {
+        this.builder = builder;
+    }
+
+}