/**
 *        CloudGraph Community Edition (CE) License
 * 
 * This is a community release of CloudGraph, a dual-license suite of
 * Service Data Object (SDO) 2.1 services designed for relational and 
 * big-table style "cloud" databases, such as HBase and others. 
 * This particular copy of the software is released under the 
 * version 2 of the GNU General Public License. CloudGraph was developed by 
 * TerraMeta Software, Inc.
 * 
 * Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
 * 
 * General License information can be found below.
 * 
 * This distribution may include materials developed by third
 * parties. For license and attribution notices for these
 * materials, please refer to the documentation that accompanies
 * this distribution (see the "Licenses for Third-Party Components"
 * appendix) or view the online documentation at 
 * <http://cloudgraph.org/licenses/>. 
 */
package org.cloudgraph.hbase.service;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.cloudgraph.state.PooledStateManager;
import org.cloudgraph.state.SimpleStateMarshallingContext;
import org.cloudgraph.state.StateMarshalingContext;

/**
 * Uses a global pool for managing {@link StateMarshalingContext} and only
 * creates an instance on demand, returning the instance to the pool on
 * {link ServiceContext.close}. 
 * 
 * @see StateMarshalingContext
 * @see PooledStateManager
 * @author Scott Cinnamond
 * @since 0.6.3
 */
public class LazyServiceContext implements ServiceContext {
    private static Log log = LogFactory.getLog(LazyServiceContext.class);
    private StateMarshalingContext marshallingContext;
    private PooledStateManager pool;
    
    @SuppressWarnings("unused")
	private LazyServiceContext() {}
    public LazyServiceContext(PooledStateManager pooledMarshallingContext) {
    	this.pool = pooledMarshallingContext;
    }
    
    @Override
	public StateMarshalingContext getMarshallingContext() {
		if (this.marshallingContext == null) {
		    if (log.isDebugEnabled())
			    log.debug("getting marshalling context from pool");
    	    this.marshallingContext = new SimpleStateMarshallingContext(
    		    this.pool.getBinding());
		}
		return this.marshallingContext;
	} 
    
    @Override
    public void close() {
    	if (this.marshallingContext != null) {
		    if (log.isDebugEnabled())
			    log.debug("returning marshalling context to pool");
		    this.pool.returnBinding(this.marshallingContext.getBinding());
	        this.marshallingContext = null;
    	}
    }
}