JavaBeanReferenceMaker.java

/*
 * Distributed as part of mchange-commons-java 0.2.11
 *
 * Copyright (C) 2015 Machinery For Change, Inc.
 *
 * Author: Steve Waldman <swaldman@mchange.com>
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of EITHER:
 *
 *     1) The GNU Lesser General Public License (LGPL), version 2.1, as 
 *        published by the Free Software Foundation
 *
 * OR
 *
 *     2) The Eclipse Public License (EPL), version 1.0
 *
 * You may choose which license to accept if you wish to redistribute
 * or modify this work. You may offer derivatives of this work
 * under the license you have chosen, or you may provide the same
 * choice of license which you have been offered here.
 *
 * 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.
 *
 * You should have received copies of both LGPL v2.1 and EPL v1.0
 * along with this software; see the files LICENSE-EPL and LICENSE-LGPL.
 * If not, the text of these licenses are currently available at
 *
 * LGPL v2.1: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 *  EPL v1.0: http://www.eclipse.org/org/documents/epl-v10.php 
 * 
 */

package com.mchange.v2.naming;

import java.beans.*;
import java.io.*;
import java.util.*;
import javax.naming.*;
import com.mchange.v2.log.*;
import java.lang.reflect.Method;
import com.mchange.v2.lang.Coerce;
import com.mchange.v2.beans.BeansUtils;
import com.mchange.v2.ser.SerializableUtils;
import com.mchange.v2.ser.IndirectPolicy;

public class JavaBeanReferenceMaker implements ReferenceMaker
{
    private final static MLogger logger = MLog.getLogger( JavaBeanReferenceMaker.class );

    final static String REF_PROPS_KEY = "com.mchange.v2.naming.JavaBeanReferenceMaker.REF_PROPS_KEY";

    final static Object[] EMPTY_ARGS = new Object[0];

    final static byte[] NULL_TOKEN_BYTES = new byte[0];

    String factoryClassName = "com.mchange.v2.naming.JavaBeanObjectFactory";
    String defaultFactoryClassLocation = null;

    Set referenceProperties = new HashSet();

    ReferenceIndirector indirector = new ReferenceIndirector();

    public Hashtable getEnvironmentProperties()
    { return indirector.getEnvironmentProperties(); }

    public void setEnvironmentProperties( Hashtable environmentProperties )
    { indirector.setEnvironmentProperties( environmentProperties ); }

    public void setFactoryClassName(String factoryClassName)
    { this.factoryClassName = factoryClassName; }

    public String getFactoryClassName()
    { return factoryClassName; }

    public String getDefaultFactoryClassLocation()
    { return defaultFactoryClassLocation; }

    public void setDefaultFactoryClassLocation( String defaultFactoryClassLocation )
    { this.defaultFactoryClassLocation = defaultFactoryClassLocation; }

    public void addReferenceProperty( String propName )
    { referenceProperties.add( propName ); }

    public void removeReferenceProperty( String propName )
    { referenceProperties.remove( propName ); }

    public Reference createReference( Object bean )
	throws NamingException
    {
	try
	    {
		BeanInfo bi = Introspector.getBeanInfo( bean.getClass() );
		PropertyDescriptor[] pds = bi.getPropertyDescriptors();
		List refAddrs = new ArrayList();
		String factoryClassLocation = defaultFactoryClassLocation;

		boolean using_ref_props = referenceProperties.size() > 0;

		// we only include this so that on dereference we are not surprised to find some properties missing
		if (using_ref_props)
		    refAddrs.add( new BinaryRefAddr( REF_PROPS_KEY, SerializableUtils.toByteArray( referenceProperties ) ) );

		for (int i = 0, len = pds.length; i < len; ++i)
		    {
			PropertyDescriptor pd = pds[i];
			String propertyName = pd.getName();
			//System.err.println("Making Reference: " + propertyName);

			if (using_ref_props && ! referenceProperties.contains( propertyName ))
			    {
				//System.err.println("Not a ref_prop -- continuing.");
				continue;
			    }

			Class  propertyType = pd.getPropertyType();
			Method getter = pd.getReadMethod();
			Method setter = pd.getWriteMethod();
			if (getter != null && setter != null) //only use properties that are both readable and writable
			    {
				Object val = getter.invoke( bean, EMPTY_ARGS );
				//System.err.println( "val: " + val );
				if (propertyName.equals("factoryClassLocation"))
				    {
					if (String.class != propertyType)
					    throw new NamingException(this.getClass().getName() + " requires a factoryClassLocation property to be a string, " +
								      propertyType.getName() + " is not valid.");
					factoryClassLocation = (String) val;
				    }

				if (val == null)
				    {
					RefAddr addMe = new BinaryRefAddr( propertyName, NULL_TOKEN_BYTES );
					refAddrs.add( addMe );
				    }
				else if ( Coerce.canCoerce( propertyType ) )
				    {
					RefAddr addMe = new StringRefAddr( propertyName, String.valueOf( val ) );
					refAddrs.add( addMe );
				    }
				else  //other Object properties
				    {
					RefAddr addMe = null;
					PropertyEditor pe = BeansUtils.findPropertyEditor( pd );
					if (pe != null)
					    {
						pe.setValue( val );
						String textValue = pe.getAsText();
						if (textValue != null)
						    addMe = new StringRefAddr( propertyName, textValue );
					    }
					if (addMe == null) //property editor approach failed
					    addMe = new BinaryRefAddr( propertyName, SerializableUtils.toByteArray( val, 
														    indirector, 
														    IndirectPolicy.INDIRECT_ON_EXCEPTION ) );
					refAddrs.add( addMe );
				    }
			    }
			else
			    {
// 				System.err.println(this.getClass().getName() +
// 						   ": Skipping " + propertyName + " because it is " + (setter == null ? "read-only." : "write-only."));

				if ( logger.isLoggable( MLevel.WARNING ) )
				    logger.warning(this.getClass().getName() + ": Skipping " + propertyName + 
						   " because it is " + (setter == null ? "read-only." : "write-only."));
			    }

		    }
		Reference out = new Reference( bean.getClass().getName(), factoryClassName, factoryClassLocation );
		for (Iterator ii = refAddrs.iterator(); ii.hasNext(); )
		    out.add( (RefAddr) ii.next() );
		return out;
	    }
	catch ( Exception e )
	    {
		//e.printStackTrace();
		if ( Debug.DEBUG && logger.isLoggable( MLevel.FINE ) )
		    logger.log( MLevel.FINE, "Exception trying to create Reference.", e);

		throw new NamingException("Could not create reference from bean: " + e.toString() );
	    }
    }

}