1 package org.apache.velocity.tools.config;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.velocity.runtime.log.Log;
23
24 /**
25 * This allows for a {@link Log} to optionally be attached to
26 * a subclass in order to output logging messages. This is simpler
27 * than constantly checking whether we have a Log or not in each
28 * usage throughout the classes which could use logging. Methods should
29 * only be added to this as necessary. Performance considerations
30 * can also be made later if deemed necessary. This is meant for internal
31 * use and should NOT be relied upon by VelocityTools users.
32 *
33 * @author Nathan Bubna
34 * @version $Id: LogSupport.java 511959 2007-02-26 19:24:39Z nbubna $
35 */
36 public abstract class LogSupport
37 {
38 private static final String DEFAULT_PREFIX = "";
39 private Log log;
40
41 /**
42 * Override this to set a class-specific prefix
43 */
44 protected String logPrefix()
45 {
46 return DEFAULT_PREFIX;
47 }
48
49 public void setLog(Log log)
50 {
51 this.log = log;
52 }
53
54 protected Log getLog()
55 {
56 return this.log;
57 }
58
59 protected boolean isWarnEnabled()
60 {
61 return (log != null && log.isWarnEnabled());
62 }
63
64 protected void warn(String msg)
65 {
66 if (isWarnEnabled())
67 {
68 log.warn(logPrefix() + msg);
69 }
70 }
71
72 protected boolean isDebugEnabled()
73 {
74 return (log != null && log.isDebugEnabled());
75 }
76
77 protected void debug(String msg)
78 {
79 if (isDebugEnabled())
80 {
81 log.debug(logPrefix() + msg);
82 }
83 }
84
85 protected boolean isTraceEnabled()
86 {
87 return (log != null && log.isTraceEnabled());
88 }
89
90 protected void trace(String msg)
91 {
92 if (isTraceEnabled())
93 {
94 log.trace(logPrefix() + msg);
95 }
96 }
97
98 }