001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. 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 */
017package org.apache.logging.log4j.core.filter;
018
019import java.util.Iterator;
020
021import org.apache.logging.log4j.core.AbstractLifeCycle;
022import org.apache.logging.log4j.core.Filter;
023import org.apache.logging.log4j.core.LogEvent;
024
025/**
026 * Enhances a Class by allowing it to contain Filters.
027 */
028public abstract class AbstractFilterable extends AbstractLifeCycle implements Filterable {
029
030    /**
031     * May be null.
032     */
033    private volatile Filter filter;
034
035    protected AbstractFilterable(final Filter filter) {
036        this.filter = filter;
037    }
038
039    protected AbstractFilterable() {
040    }
041
042    /**
043     * Returns the Filter.
044     * @return the Filter or null.
045     */
046    @Override
047    public Filter getFilter() {
048        return filter;
049    }
050
051    /**
052     * Adds a filter.
053     * @param filter The Filter to add.
054     */
055    @Override
056    public synchronized void addFilter(final Filter filter) {
057        if (this.filter == null) {
058            this.filter = filter;
059        } else if (filter instanceof CompositeFilter) {
060            this.filter = ((CompositeFilter) this.filter).addFilter(filter);
061        } else {
062            final Filter[] filters = new Filter[] {this.filter, filter};
063            this.filter = CompositeFilter.createFilters(filters);
064        }
065    }
066
067    /**
068     * Removes a Filter.
069     * @param filter The Filter to remove.
070     */
071    @Override
072    public synchronized void removeFilter(final Filter filter) {
073        if (this.filter == filter) {
074            this.filter = null;
075        } else if (filter instanceof CompositeFilter) {
076            CompositeFilter composite = (CompositeFilter) filter;
077            composite = composite.removeFilter(filter);
078            if (composite.size() > 1) {
079                this.filter = composite;
080            } else if (composite.size() == 1) {
081                final Iterator<Filter> iter = composite.iterator();
082                this.filter = iter.next();
083            } else {
084                this.filter = null;
085            }
086        }
087    }
088
089    /**
090     * Determines if a Filter is present.
091     * @return false if no Filter is present.
092     */
093    @Override
094    public boolean hasFilter() {
095        return filter != null;
096    }
097
098    /**
099     * Make the Filter available for use.
100     */
101    @Override
102    public void start() {
103        this.setStarting();
104        if (filter != null) {
105            filter.start();
106        }
107        this.setStarted();
108    }
109
110    /**
111     * Cleanup the Filter.
112     */
113    @Override
114    public void stop() {
115        this.setStopping();
116       if (filter != null) {
117           filter.stop();
118       }
119       this.setStopped();
120    }
121
122    /**
123     * Determine if the LogEvent should be processed or ignored.
124     * @param event The LogEvent.
125     * @return true if the LogEvent should be processed.
126     */
127    @Override
128    public boolean isFiltered(final LogEvent event) {
129        return filter != null && filter.filter(event) == Filter.Result.DENY;
130    }
131
132}