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30 day Evaluation Version distributed via the Maven Jar Repository. Clover is not free. You have 30 days to evaluate it. Please visit http://www.thecortex.net/clover to obtain a licensed version of Clover | |||||||||||||||||||
Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
AbstractMasterConverter.java | 0% | 0% | 0% | 0% |
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/*
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* Copyright (C) The Spice Group. All rights reserved.
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*
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* This software is published under the terms of the Spice
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* Software License version 1.1, a copy of which has been included
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* with this distribution in the LICENSE.txt file.
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*/
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package org.codehaus.spice.converter;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.Map;
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import org.codehaus.spice.salt.i18n.Resources;
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import org.codehaus.spice.salt.i18n.ResourceManager;
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/**
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* This is a Converter implementation that is capable of converting between
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* many different source and destination types, by delegating delegates to
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* other converters that do the actual work.
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*
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* <p>To use this class you must subclass it, and register some converters
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* using the (@link #registerConverter} method.</p>
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*
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* @author Peter Donald
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* @version $Revision: 1.1 $ $Date: 2003/12/02 08:37:56 $
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*/
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public abstract class AbstractMasterConverter |
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implements Converter
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{ |
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/**
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* i18n resources accessor.
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*/
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private static final Resources REZ = |
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ResourceManager.getPackageResources( AbstractMasterConverter.class );
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/**
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* Cache of converter instances. This is a map from ConverterFactory to
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* a Converter instance created by that factory.
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*/
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private final Map m_converters = new HashMap(); |
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/**
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* This holds the mapping between source/destination and ConverterFactory.
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*/
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private final HashMap m_mapping = new HashMap(); |
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/**
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* Convert object to destination type.
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*
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* @param destination the destination type
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* @param original the original object
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* @param context the context in which to convert
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* @return the converted object
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* @throws ConverterException if an error occurs
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*/
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public Object convert( final Class destination,
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final Object original, |
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final Object context ) |
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throws ConverterException
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{ |
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final Class originalClass = original.getClass(); |
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if( destination.isAssignableFrom( originalClass ) )
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{ |
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return original;
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} |
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try
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{ |
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// Determine which converter to use
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final Converter converter = findConverter( originalClass, destination ); |
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// Convert
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final Object object = converter.convert( destination, original, context ); |
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if( destination.isInstance( object ) )
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{ |
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return object;
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} |
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final String message = |
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REZ.format( "bad-return-type.error",
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object.getClass().getName(), |
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destination.getName() ); |
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throw new ConverterException( message ); |
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} |
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catch( final Exception e )
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{ |
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final String message = |
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REZ.format( "convert.error",
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originalClass.getName(), |
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destination.getName() ); |
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throw new ConverterException( message, e ); |
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} |
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} |
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/**
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* Returns the Converter instance to use to convert between a particular
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* pair of classes.
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*/
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private Converter findConverter( final Class originalClass,
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final Class destination ) |
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throws Exception
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{ |
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// Locate the factory to use
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final ConverterFactory factory = findConverterFactory( originalClass, destination ); |
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// Create the converter
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Converter converter = (Converter)m_converters.get( factory ); |
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if( converter == null ) |
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{ |
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converter = factory.createConverter(); |
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m_converters.put( factory, converter ); |
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} |
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return converter;
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} |
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/**
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* Register a converter
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*
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* @param factory the factory to use to create converter instances.
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* @param source the source classname
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* @param destination the destination classname
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*/
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protected void registerConverter( final ConverterFactory factory, |
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final String source, |
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final String destination ) |
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{ |
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HashMap map = (HashMap)m_mapping.get( source ); |
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if( null == map ) |
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{ |
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map = new HashMap();
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m_mapping.put( source, map ); |
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} |
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map.put( destination, factory ); |
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//Remove instance of converter if it has already been created
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m_converters.remove( factory ); |
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} |
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/**
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* Determine the type of converter (represented as a ConverterFactory) to
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* use to convert between original and destination classes.
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*/
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private ConverterFactory findConverterFactory( final Class originalClass,
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final Class destination ) |
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throws ConverterException
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{ |
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//TODO: Maybe we should search the destination classes hierarchy as well
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// Recursively iterate over the super-types of the original class,
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// looking for a converter from source type -> destination type.
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// If more than one is found, choose the most specialised.
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Class bestSrcMatch = null;
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ConverterFactory matchFactory = null;
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ArrayList queue = new ArrayList();
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queue.add( originalClass ); |
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while( !queue.isEmpty() )
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{ |
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final Class clazz = (Class)queue.remove( 0 ); |
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// Add superclass and all interfaces
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if( clazz.getSuperclass() != null ) |
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{ |
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queue.add( clazz.getSuperclass() ); |
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} |
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final Class[] interfaces = clazz.getInterfaces(); |
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for( int i = 0; i < interfaces.length; i++ ) |
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{ |
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queue.add( interfaces[ i ] ); |
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} |
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// Check if we can convert from current class to destination
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final ConverterFactory factory = |
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getConverterFactory( clazz.getName(), destination.getName() ); |
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if( factory == null ) |
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{ |
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continue;
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} |
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// Choose the more specialised source class
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if( bestSrcMatch == null || bestSrcMatch.isAssignableFrom( clazz ) ) |
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{ |
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bestSrcMatch = clazz; |
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matchFactory = factory; |
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} |
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else if( clazz.isAssignableFrom( bestSrcMatch ) ) |
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{ |
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continue;
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} |
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else
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{ |
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// Duplicate
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final String message = REZ.getString( "ambiguous-converter.error" );
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throw new ConverterException( message ); |
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} |
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} |
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// TODO - should cache the (src, dest) -> converter mapping
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if( bestSrcMatch != null ) |
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{ |
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return matchFactory;
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} |
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// Could not find a converter
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final String message = REZ.getString( "no-converter.error" );
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throw new ConverterException( message ); |
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} |
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/**
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* Retrieve factory for the converter that converts from source to destination.
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*/
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private ConverterFactory getConverterFactory( final String source,
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final String destination ) |
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{ |
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final HashMap map = (HashMap)m_mapping.get( source ); |
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if( null == map ) |
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{ |
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return null; |
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} |
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return (ConverterFactory)map.get( destination );
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} |
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} |
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