com.zenesis.qx.remote.SimpleQueue.java Source code

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Here is the source code for com.zenesis.qx.remote.SimpleQueue.java

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/**
 * ************************************************************************
 * 
 *    server-objects - a contrib to the Qooxdoo project that makes server 
 *    and client objects operate seamlessly; like Qooxdoo, server objects 
 *    have properties, events, and methods all of which can be access from
 *    either server or client, regardless of where the original object was
 *    created.
 * 
 *    http://qooxdoo.org
 * 
 *    Copyright:
 *      2010 Zenesis Limited, http://www.zenesis.com
 * 
 *    License:
 *      LGPL: http://www.gnu.org/licenses/lgpl.html
 *      EPL: http://www.eclipse.org/org/documents/epl-v10.php
 *      
 *      This software is provided under the same licensing terms as Qooxdoo,
 *      please see the LICENSE file in the Qooxdoo project's top-level directory 
 *      for details.
 * 
 *    Authors:
 *      * John Spackman (john.spackman@zenesis.com)
 * 
 * ************************************************************************
 */
package com.zenesis.qx.remote;

import java.io.IOException;
import java.util.LinkedHashMap;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializable;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.zenesis.qx.remote.CommandId.CommandType;

/**
 * Simplistic but functional QueueWriter; all property values are sent first, 
 * followed by events.  Duplicates are merged.
 * 
 * @author John Spackman [john.spackman@zenesis.com]
 */
public class SimpleQueue implements CommandQueue, JsonSerializable {

    private boolean needsFlush;
    private LinkedHashMap<CommandId, Object> values = new LinkedHashMap<CommandId, Object>();

    /* (non-Javadoc)
     * @see com.zenesis.qx.remote.CommandQueue#queueCommand(com.zenesis.qx.remote.CommandId, java.lang.Object)
     */
    @Override
    public synchronized void queueCommand(CommandType type, Object object, String propertyName, Object data) {
        if (type == CommandType.BOOTSTRAP && !values.isEmpty()) {
            LinkedHashMap<CommandId, Object> tmp = new LinkedHashMap<CommandId, Object>();
            tmp.put(new CommandId(type, object, propertyName), data);
            tmp.putAll(values);
            values = tmp;
        } else
            values.put(new CommandId(type, object, propertyName), data);
    }

    /* (non-Javadoc)
     * @see com.zenesis.qx.remote.Queue#hasDataToFlush()
     */
    @Override
    public synchronized boolean hasDataToFlush() {
        return !values.isEmpty();
    }

    /* (non-Javadoc)
     * @see com.zenesis.qx.remote.Queue#needsFlush()
     */
    @Override
    public synchronized boolean needsFlush() {
        return needsFlush;
    }

    /* (non-Javadoc)
     * @see org.codehaus.jackson.map.JsonSerializable#serialize(org.codehaus.jackson.JsonGenerator, org.codehaus.jackson.map.SerializerProvider)
     */
    @Override
    public synchronized void serialize(JsonGenerator gen, SerializerProvider sp)
            throws IOException, JsonProcessingException {
        gen.writeStartArray();
        while (!values.isEmpty()) {
            CommandId id = values.keySet().iterator().next();
            Object data = values.remove(id);

            if (id.type == CommandType.DEFINE) {
                ProxyType type = (ProxyType) id.object;
                ProxySessionTracker tracker = ((ProxyObjectMapper) gen.getCodec()).getTracker();
                if (tracker.isTypeDelivered(type))
                    continue;
            }

            gen.writeStartObject();
            gen.writeStringField("type", id.type.remoteId);
            if (id.object != null)
                gen.writeObjectField("object", id.object);
            if (id.name != null)
                gen.writeObjectField("name", id.name);
            if (data != null)
                gen.writeObjectField("data", data);
            gen.writeEndObject();
        }
        gen.writeEndArray();
        values.clear();
        needsFlush = false;
    }

    /* (non-Javadoc)
     * @see com.fasterxml.jackson.databind.JsonSerializable#serializeWithType(com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider, com.fasterxml.jackson.databind.jsontype.TypeSerializer)
     */
    @Override
    public synchronized void serializeWithType(JsonGenerator gen, SerializerProvider sp, TypeSerializer ts)
            throws IOException, JsonProcessingException {
        serialize(gen, sp);
    }

}