StringifierRegistryImpl.java

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package org.glassfish.admin.amx.util.stringifier;

import java.util.HashMap;
import java.util.Map;



/**
	Holds a lookup table for Stringifiers.   Certain Stringifier classes
	may use this registry to aid them in producing suitable output.
 */
public class StringifierRegistryImpl implements StringifierRegistry
{
	public static final StringifierRegistry	DEFAULT	= new StringifierRegistryImpl();
	
	private final Map<Class<?>,Stringifier>		mLookup;
	private final StringifierRegistry			mNextRegistry;
	
	/**
		Create a new registry with no next registry.
	 */
		public
	StringifierRegistryImpl()
	{
		this( null );
	}
	
	/**
		Create a new registry which is chained to an existing registry.
		
		When lookup() is called, if it cannot be found in this registry, then
		the chainee is used.
		
		@param registry	the registry to use if this registry fails to find a Stringifier
	 */
		public
	StringifierRegistryImpl( final StringifierRegistry registry )
	{
		mLookup			= new HashMap<Class<?>,Stringifier>();
		mNextRegistry	= registry;
	}
	
		public void
	add( final Class<?> theClass, final Stringifier stringifier )
	{
		if ( lookup( theClass ) != null )
		{
			throw new IllegalArgumentException( "Stringifier already registered for: " + theClass.getName() );
		}
		
		mLookup.remove( theClass );
		mLookup.put( theClass, stringifier );
	}
	
	
		public Stringifier
	lookup( final Class<?> theClass )
	{
		Stringifier		stringifier	= mLookup.get( theClass );
		
		if ( stringifier == null && mNextRegistry != null )
		{
			stringifier	= mNextRegistry.lookup( theClass );
		}
		
		return( stringifier );
	}
}