collections.java

Java Communicating Agents是一个用于开发网络反应式信息agent的框架

/*
 * $Source: /home/data/cvsroot/src/jacomma/util/Collections.java,v $
 * $Revision: 1.4 $
 * $Date: 2000/10/28 20:09:08 $
 *
 * This file is part of the jacomma framework
 * Copyright (c) 2000 	Dimitrios Vyzovitis
 *			mailto:[e-mail]
 *			
 *
 *			
 *			
 *			
 *
 *	This library is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU Library General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This library 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.  See the
 *	GNU Library General Public License for more details.
 *
 *	You should have received a copy of the GNU Library General Public License
 *	along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, 
 *	Boston, MA  02111-1307  USA
 */

package jacomma.util;

import java.util.Map;
import java.util.Set;
import java.util.Collection;
import java.util.List;
import java.util.SortedSet;
import java.util.SortedMap;
import java.util.Hashtable;

/**
 * TBA
 **/
public class Collections {
	
	public static final Object toImmutable( Object obj ) {
		Class[] a = new Class[1];
		for ( TypeIterator it = new TypeIterator( obj );
			  it.hasMoreTypes(); ) {
			try {
				a[0] = it.nextType();
				return Collections.class.getMethod( "toImmutable", a )
					.invoke( null, new Object[]{ obj } );
			} catch ( Exception exc ){}
		}
		
		throw new RuntimeException( "Bad Object Type: Not a Collection?" );
		
	}
	
	public static final Map toImmutable( Map m ) {
		return java.util.Collections.unmodifiableMap( m );
	}

	public static final Set toImmutable( Set s ) {
		return java.util.Collections.unmodifiableSet( s );
	}
	
	public static final Collection toImmutable( Collection c ) {
		return java.util.Collections.unmodifiableCollection( c );
	}
	
	public static final List toImmutable( List l ) {
		return java.util.Collections.unmodifiableList( l );
	}
	
	public static final SortedSet toImmutable( SortedSet s ) {
		return java.util.Collections.unmodifiableSortedSet( s );
	}
	
	public static final SortedMap toImmutable( SortedMap m ) {
		return java.util.Collections.unmodifiableSortedMap( m );
	}
	
	public static final Object reifyImmutable( Object obj ) {
		try {
			return obj.getClass().getMethod( "clone", null ).invoke( obj, null );
		} catch ( Exception exc ) {
			// ok, do the magic
			try {
				java.lang.reflect.Constructor c = 
					(java.lang.reflect.Constructor)bindings_.get( obj.getClass() );
				return c.newInstance( new Object[]{ obj } );
			} catch ( Exception exc2 ) {
				exc2.printStackTrace();
				throw new RuntimeException( "Bad Object type: Not an immutable collection?" );
			}
		}
	}

	public static final Object toSynchronized( Object obj ) {
		Class[] a = new Class[1];
		for ( TypeIterator it = new TypeIterator( obj );
			  it.hasMoreTypes(); ) {
			try {
				a[0] = it.nextType();
				return Collections.class.getMethod( "toSynchronized", a )
					.invoke( null, new Object[]{ obj } );
			} catch ( Exception exc ){}
		}
		
		throw new RuntimeException( "Bad Object Type: Not a Collection?" );
		
	}
	
	public static final Map toSynchronized( Map m ) {
		return java.util.Collections.synchronizedMap( m );
	}

	public static final Set toSynchronized( Set s ) {
		return java.util.Collections.synchronizedSet( s );
	}
	
	public static final Collection toSynchronized( Collection c ) {
		return java.util.Collections.synchronizedCollection( c );
	}
	
	public static final List toSynchronized( List l ) {
		return java.util.Collections.synchronizedList( l );
	}
	
	public static final SortedSet toSynchronized( SortedSet s ) {
		return java.util.Collections.synchronizedSortedSet( s );
	}
	
	public static final SortedMap toSynchronized( SortedMap m ) {
		return java.util.Collections.synchronizedSortedMap( m );
	}


	static final Hashtable bindings_;
	
	static {
		try {
			bindings_ = new Hashtable();
			// a bit of a hack...
			// the alternative solution is to do it with priviledge access, which is
			// unecessary complicated ;-)
			String[] types = { "java.util.Collections$UnmodifiableCollection",
							   "java.util.Collections$UnmodifiableSet",
							   "java.util.Collections$UnmodifiableList",
							   "java.util.Collections$UnmodifiableMap",
							   "java.util.Collections$UnmodifiableSortedSet",
							   "java.util.Collections$UnmodifiableSortedMap" };
			Class[] bds = { java.util.Vector.class,
							java.util.HashSet.class ,
							java.util.ArrayList.class,
							java.util.HashMap.class,
							java.util.TreeSet.class,
							java.util.TreeMap.class };
			Class[] tgt = { Collection.class,
							Collection.class,
							Collection.class,
							Map.class,
							SortedSet.class,
							SortedMap.class };
			
			Class[] t = new Class[1];
			for ( int i = 0; i < types.length; i++ ) {
				t[0] = tgt[i];
				bindings_.put( Class.forName( types[i] ), bds[i].getConstructor( t ) );
			}
		} catch ( Exception exc ) {
			exc.printStackTrace();
			throw new RuntimeException( "Oops... Error setting up immutable collection reification." );
		}
	}
		
}