001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     * 
010     *      http://www.apache.org/licenses/LICENSE-2.0
011     * 
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.oozie.util;
019    
020    import org.apache.oozie.util.XLogStreamer;
021    
022    import java.util.ArrayList;
023    import java.io.Writer;
024    import java.io.IOException;
025    import java.io.BufferedReader;
026    import java.io.InputStreamReader;
027    import java.io.InputStream;
028    
029    /**
030     * Reads the input stream(log file) and applies the filters and writes it to output stream. The filtering will also
031     * consider the log messages spilling over multiline.
032     */
033    public class XLogReader {
034        private BufferedReader logReader;
035        private Writer logWriter;
036        private boolean noFilter = false;
037        private XLogStreamer.Filter logFilter;
038    
039        public XLogReader(InputStream logFileIS, XLogStreamer.Filter filter, Writer logWriter) {
040            logReader = new BufferedReader(new InputStreamReader(logFileIS));
041            logFilter = filter;
042            this.logWriter = logWriter;
043        }
044    
045        /**
046         * Processes the Given Log and writes the output after applying the filters.
047         *
048         * @throws IOException
049         */
050        public void processLog() throws IOException {
051            String line = logReader.readLine();
052            boolean patternMatched = false;
053            int lcnt = 0;
054            if (logFilter == null || !logFilter.isFilterPresent()) {
055                noFilter = true;
056            }
057            else {
058                logFilter.constructPattern();
059            }
060            while (line != null) {
061                if (noFilter) {
062                    logWriter.write(line + "\n");
063                }
064                else {
065                    ArrayList<String> logParts = logFilter.splitLogMessage(line);
066                    if (logParts != null) {
067                        patternMatched = logFilter.matches(logParts);
068                    }
069                    if (patternMatched) {
070                        logWriter.write(line + "\n");
071                    }
072                }
073                lcnt++;
074                if (lcnt % 20 == 0) {
075                    logWriter.flush();
076                }
077                line = logReader.readLine();
078            }
079            logWriter.flush();
080        }
081    
082        public void close() throws IOException {
083            logReader.close();
084        }
085    }