001 /* 002 Copyright (C) 2001 Laurent Martelli <laurent@aopsys.com> 003 004 This program is free software; you can redistribute it and/or modify 005 it under the terms of the GNU Lesser General Public License as 006 published by the Free Software Foundation; either version 2 of the 007 License, or (at your option) any later version. 008 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU Lesser General Public License for more details. 013 014 You should have received a copy of the GNU Lesser General Public License 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ 017 018 package org.objectweb.jac.util; 019 020 import java.util.Collection; 021 import java.util.Iterator; 022 import java.util.List; 023 024 025 /** 026 * A Predicate class. 027 * 028 * @author <a href="mailto:laurent@aopsys.com">Laurent Martelli</a> 029 */ 030 031 public abstract class Predicate { 032 public abstract boolean apply(Object object); 033 /** 034 * Keeps only the items matching the predicate from a collection 035 * @param in filter items from that collection 036 * @param out matching items are added to this collection 037 */ 038 public void filter(Collection in, Collection out) { 039 Iterator i = in.iterator(); 040 while (i.hasNext()) { 041 Object item = i.next(); 042 if (apply(item)) { 043 out.add(item); 044 } 045 } 046 } 047 }