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    private static final long serialVersionUID = 1L;
031
032    /**
033     * May be null.
034     */
035    private volatile Filter filter;
036
037    protected AbstractFilterable(final Filter filter) {
038        this.filter = filter;
039    }
040
041    protected AbstractFilterable() {
042    }
043
044    /**
045     * Returns the Filter.
046     * @return the Filter or null.
047     */
048    @Override
049    public Filter getFilter() {
050        return filter;
051    }
052
053    /**
054     * Adds a filter.
055     * @param filter The Filter to add.
056     */
057    @Override
058    public synchronized void addFilter(final Filter filter) {
059        if (this.filter == null) {
060            this.filter = filter;
061        } else if (filter instanceof CompositeFilter) {
062            this.filter = ((CompositeFilter) this.filter).addFilter(filter);
063        } else {
064            final Filter[] filters = new Filter[] {this.filter, filter};
065            this.filter = CompositeFilter.createFilters(filters);
066        }
067    }
068
069    /**
070     * Removes a Filter.
071     * @param filter The Filter to remove.
072     */
073    @Override
074    public synchronized void removeFilter(final Filter filter) {
075        if (this.filter == filter) {
076            this.filter = null;
077        } else if (filter instanceof CompositeFilter) {
078            CompositeFilter composite = (CompositeFilter) filter;
079            composite = composite.removeFilter(filter);
080            if (composite.size() > 1) {
081                this.filter = composite;
082            } else if (composite.size() == 1) {
083                final Iterator<Filter> iter = composite.iterator();
084                this.filter = iter.next();
085            } else {
086                this.filter = null;
087            }
088        }
089    }
090
091    /**
092     * Determines if a Filter is present.
093     * @return false if no Filter is present.
094     */
095    @Override
096    public boolean hasFilter() {
097        return filter != null;
098    }
099
100    /**
101     * Make the Filter available for use.
102     */
103    @Override
104    public void start() {
105        this.setStarting();
106        if (filter != null) {
107            filter.start();
108        }
109        this.setStarted();
110    }
111
112    /**
113     * Cleanup the Filter.
114     */
115    @Override
116    public void stop() {
117        this.setStopping();
118       if (filter != null) {
119           filter.stop();
120       }
121       this.setStopped();
122    }
123
124    /**
125     * Determine if the LogEvent should be processed or ignored.
126     * @param event The LogEvent.
127     * @return true if the LogEvent should be processed.
128     */
129    @Override
130    public boolean isFiltered(final LogEvent event) {
131        return filter != null && filter.filter(event) == Filter.Result.DENY;
132    }
133
134}