Java tutorial
/** * Helios, OpenSource Monitoring * Brought to you by the Helios Development Group * * Copyright 2012, Helios Development Group and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. * */ package org.helios.apmrouter.dataservice.json.marshalling; import java.lang.reflect.Type; import java.net.SocketAddress; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.CopyOnWriteArraySet; import org.helios.apmrouter.OpCode; import org.helios.apmrouter.server.ServerComponentBean; import org.jboss.netty.buffer.ChannelBuffer; import org.jboss.netty.buffer.ChannelBuffers; import org.jboss.netty.channel.Channel; import org.json.JSONObject; import org.springframework.jmx.export.annotation.ManagedAttribute; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.TypeAdapterFactory; /** * <p>Title: GSONJSONMarshaller</p> * <p>Description: JSON marshalling service, implemented using <a href="https://sites.google.com/site/gson/">Google-gson</a>to centralize the marshalling of outgoing objects into json.</p> * <p>Company: Helios Development Group LLC</p> * @author Whitehead (nwhitehead AT heliosdev DOT org) * <p><code>org.helios.apmrouter.dataservice.json.marshalling.GSONJSONMarshaller</code></p> */ public class GSONJSONMarshaller extends ServerComponentBean implements JSONMarshaller { /** Sets the pretty-print attribute of the gson builder */ protected boolean prettyPrint = false; /** Sets the HTML escaping attribute of the gson builder */ protected boolean disableHtmlEscaping = false; /** Sets the null serialization attribute of the gson builder */ protected boolean serializeNulls = false; /** Custom type adapters */ protected final Map<Type, Object> adapterInstances = new ConcurrentHashMap<Type, Object>(); /** Custom type adapter factories */ protected final Set<TypeAdapterFactory> adapterFactoryInstances = new CopyOnWriteArraySet<TypeAdapterFactory>(); /** The gson instance */ protected Gson gson = null; /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(java.lang.Object) */ public ChannelBuffer marshallToChannel(Object obj) { return marshallToChannel(null, obj); } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(org.helios.apmrouter.OpCode, java.lang.Object) */ public ChannelBuffer marshallToChannel(OpCode opCode, Object obj) { if (obj == null) return ChannelBuffers.buffer(0); byte[] bytes = null; if (obj instanceof CharSequence || obj instanceof JSONObject) { bytes = obj.toString().getBytes(); } else { bytes = gson.toJson(obj).getBytes(); } ChannelBuffer cb = ChannelBuffers.directBuffer(bytes.length + (opCode == null ? 0 : 5)); if (opCode != null) { cb.writeByte(opCode.op()); cb.writeInt(bytes.length); } cb.writeBytes(bytes); bytes = null; return cb; } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(org.helios.apmrouter.OpCode, java.lang.Object, org.jboss.netty.channel.Channel) */ public void marshallToChannel(OpCode op, Object obj, Channel channel) { channel.write(marshallToChannel(op, obj)); } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(java.lang.Object, org.jboss.netty.channel.Channel) */ public void marshallToChannel(Object obj, Channel channel) { channel.write(marshallToChannel(null, obj)); } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(org.helios.apmrouter.OpCode, java.lang.Object, org.jboss.netty.channel.Channel, java.net.SocketAddress) */ public void marshallToChannel(OpCode op, Object obj, Channel channel, SocketAddress sa) { channel.write(marshallToChannel(op, obj), sa == null ? channel.getRemoteAddress() : sa); } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToChannel(java.lang.Object, org.jboss.netty.channel.Channel, java.net.SocketAddress) */ public void marshallToChannel(Object obj, Channel channel, SocketAddress sa) { channel.write(marshallToChannel(null, obj), sa == null ? channel.getRemoteAddress() : sa); } /** * {@inheritDoc} * @see org.helios.apmrouter.dataservice.json.marshalling.JSONMarshaller#marshallToText(java.lang.Object) */ public String marshallToText(Object obj) { if (obj == null) return ""; if (obj instanceof CharSequence || obj instanceof JSONObject) { return obj.toString(); } return gson.toJson(obj); } /** * {@inheritDoc} * @see org.helios.apmrouter.server.ServerComponentBean#doStart() */ @Override protected void doStart() throws Exception { super.doStart(); update(); } /** * Creates a new Gson instance based on the settings in this bean. */ protected void update() { GsonBuilder builder = new GsonBuilder(); if (prettyPrint) builder.setPrettyPrinting(); if (disableHtmlEscaping) builder.disableHtmlEscaping(); if (!adapterInstances.isEmpty()) { for (Map.Entry<Type, Object> entry : adapterInstances.entrySet()) { builder.registerTypeAdapter(entry.getKey(), entry.getValue()); } } if (!adapterFactoryInstances.isEmpty()) { for (TypeAdapterFactory taf : adapterFactoryInstances) { builder.registerTypeAdapterFactory(taf); } } gson = builder.create(); } /** * Returns the pretty print attribute * @return the pretty print attribute */ @ManagedAttribute(description = "The JSON pretty print attribute") public boolean isPrettyPrint() { return prettyPrint; } /** * Sets the pretty print attribute * @param prettyPrint true to pretty-print, false for compact */ @ManagedAttribute(description = "The JSON pretty print attribute") public void setPrettyPrint(boolean prettyPrint) { this.prettyPrint = prettyPrint; update(); } /** * Returns the html escaping disabled attribute * @return true if html escaping is enabled, false if it disabled. */ @ManagedAttribute(description = "The html escaping disabled attribute") public boolean isDisableHtmlEscaping() { return disableHtmlEscaping; } /** * Sets the html escaping disabled attribute * @param disableHtmlEscaping true to disable html escaping, false to enable */ @ManagedAttribute(description = "The html escaping disabled attribute") public void setDisableHtmlEscaping(boolean disableHtmlEscaping) { this.disableHtmlEscaping = disableHtmlEscaping; update(); } /** * Returns the serialize nulls attribute * @return true if nulls are being serialized, false otherwise */ @ManagedAttribute(description = "The null serialization attribute") public boolean isSerializeNulls() { return serializeNulls; } /** * Sets the null serialization attribute * @param serializeNulls true to serialize nulls, false otherwise */ @ManagedAttribute(description = "The null serialization attribute") public void setSerializeNulls(boolean serializeNulls) { this.serializeNulls = serializeNulls; } /** * Adds the passed map of adapter instances to the gson builder * @param adapterInstances the adapterInstances to set */ public void setAdapterInstances(Map<Type, Object> adapterInstances) { this.adapterInstances.putAll(adapterInstances); } /** * Adds the passed set of adapter factory instances to the gson builder * @param adapterFactoryInstances the adapterFactoryInstances to set */ public void setAdapterFactoryInstances(Set<TypeAdapterFactory> adapterFactoryInstances) { this.adapterFactoryInstances.addAll(adapterFactoryInstances); } }