1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.pipeline.stage;
19
20 import org.apache.commons.pipeline.StageException;
21 import org.apache.commons.pipeline.stage.BaseStage;
22 import java.util.Queue;
23 import org.apache.commons.logging.Log;
24 import org.apache.commons.logging.LogFactory;
25
26
27 /**
28 * A do-nothing implementation of Stage that simply logs the state of processing.
29 * and each object seen by its {@link #process(Object)} method.
30 * Useful for debugging purposes.
31 */
32 public class LogStage extends BaseStage {
33 private Log log = LogFactory.getLog(LogStage.class);
34
35 /**
36 * Creates a new LogStage.
37 */
38 public LogStage() {
39 }
40
41 /**
42 * Logs the point at which preprocessing runs.
43 */
44 public void preprocess() throws StageException {
45 super.preprocess();
46 log.info("Stage " + this.getClass().getName() + " preprocessing.");
47 }
48
49 /**
50 * Logs the current state of an object on the queue and passes the
51 * object unchanged to the next stage in the pipeline.
52 */
53 public void process(Object obj) throws StageException {
54 log.info("Processing object " + obj);
55 this.emit(obj);
56 }
57
58 /**
59 * Logs tht point at which postprocessing runs
60 */
61 public void postprocess() throws StageException {
62 log.info("Stage " + this.getClass().getName() + " postprocessing.");
63 }
64
65 /**
66 * Logs the point at which stage resources are released.
67 */
68 public void release() {
69 log.info("Stage " + this.getClass().getName() + " released.");
70 }
71
72 /**
73 * Sets the logger.
74 */
75 public synchronized void setLog(Log log) {
76 this.log = log;
77 }
78
79 /**
80 * Sets the logger based upon the log name.
81 */
82 public synchronized void setLog(String logName) {
83 this.log = LogFactory.getLog(logName);
84 }
85
86 /**
87 * Sets the logger based upon the specified class.
88 */
89 public synchronized void setLog(Class clazz) {
90 this.log = LogFactory.getLog(clazz);
91 }
92 }