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 (filter == null) {
058            return;
059        }
060        if (this.filter == null) {
061            this.filter = filter;
062        } else if (this.filter instanceof CompositeFilter) {
063            this.filter = ((CompositeFilter) this.filter).addFilter(filter);
064        } else {
065            final Filter[] filters = new Filter[] {this.filter, filter};
066            this.filter = CompositeFilter.createFilters(filters);
067        }
068    }
069
070    /**
071     * Removes a Filter.
072     * @param filter The Filter to remove.
073     */
074    @Override
075    public synchronized void removeFilter(final Filter filter) {
076        if (this.filter == null || filter == null) {
077            return;
078        }
079        if (this.filter == filter || this.filter.equals(filter)) {
080            this.filter = null;
081        } else if (this.filter instanceof CompositeFilter) {
082            CompositeFilter composite = (CompositeFilter) this.filter;
083            composite = composite.removeFilter(filter);
084            if (composite.size() > 1) {
085                this.filter = composite;
086            } else if (composite.size() == 1) {
087                final Iterator<Filter> iter = composite.iterator();
088                this.filter = iter.next();
089            } else {
090                this.filter = null;
091            }
092        }
093    }
094
095    /**
096     * Determines if a Filter is present.
097     * @return false if no Filter is present.
098     */
099    @Override
100    public boolean hasFilter() {
101        return filter != null;
102    }
103
104    /**
105     * Make the Filter available for use.
106     */
107    @Override
108    public void start() {
109        this.setStarting();
110        if (filter != null) {
111            filter.start();
112        }
113        this.setStarted();
114    }
115
116    /**
117     * Cleanup the Filter.
118     */
119    @Override
120    public void stop() {
121        this.setStopping();
122       if (filter != null) {
123           filter.stop();
124       }
125       this.setStopped();
126    }
127
128    /**
129     * Determine if the LogEvent should be processed or ignored.
130     * @param event The LogEvent.
131     * @return true if the LogEvent should be processed.
132     */
133    @Override
134    public boolean isFiltered(final LogEvent event) {
135        return filter != null && filter.filter(event) == Filter.Result.DENY;
136    }
137
138}