001/**
002 *
003 * Copyright 2003-2007 Jive Software.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.jivesoftware.smack.filter;
019
020import org.jivesoftware.smack.packet.Stanza;
021import org.jivesoftware.smack.util.Objects;
022
023/**
024 * Implements the logical NOT operation on a stanza filter. In other words, packets
025 * pass this filter if they do not pass the supplied filter.
026 *
027 * @author Matt Tucker
028 */
029public class NotFilter implements StanzaFilter {
030
031    private final StanzaFilter filter;
032
033    /**
034     * Creates a NOT filter using the specified filter.
035     *
036     * @param filter the filter.
037     */
038    public NotFilter(StanzaFilter filter) {
039        this.filter = Objects.requireNonNull(filter, "Parameter must not be null.");
040    }
041
042    @Override
043    public boolean accept(Stanza packet) {
044        return !filter.accept(packet);
045    }
046}