001: /*
002: * Copyright 2002-2005 the original author or authors.
003: *
004: * Licensed under the Apache License, Version 2.0 (the "License");
005: * you may not use this file except in compliance with the License.
006: * You may obtain a copy of the License at
007: *
008: * http://www.apache.org/licenses/LICENSE-2.0
009: *
010: * Unless required by applicable law or agreed to in writing, software
011: * distributed under the License is distributed on an "AS IS" BASIS,
012: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013: * See the License for the specific language governing permissions and
014: * limitations under the License.
015: */
016:
017: package org.springframework.util;
018:
019: import java.io.File;
020: import java.io.FileNotFoundException;
021: import java.net.URL;
022:
023: import org.apache.log4j.LogManager;
024: import org.apache.log4j.PropertyConfigurator;
025: import org.apache.log4j.xml.DOMConfigurator;
026:
027: /**
028: * Convenience class that features simple methods for custom Log4J configuration.
029: *
030: * <p>Only needed for non-default Log4J initialization, for example with a custom
031: * config location or a refresh interval. By default, Log4J will simply read its
032: * configuration from a "log4j.properties" file in the root of the class path.
033: *
034: * <p>For web environments, the analogous Log4jWebConfigurer class can be found
035: * in the web package, reading in its configuration from context-params in web.xml.
036: * In a J2EE web application, Log4J is usually set up via Log4jConfigListener or
037: * Log4jConfigServlet, delegating to Log4jWebConfigurer underneath.
038: *
039: * @author Juergen Hoeller
040: * @since 13.03.2003
041: * @see org.springframework.web.util.Log4jWebConfigurer
042: * @see org.springframework.web.util.Log4jConfigListener
043: * @see org.springframework.web.util.Log4jConfigServlet
044: */
045: public abstract class Log4jConfigurer {
046:
047: /** Pseudo URL prefix for loading from the class path: "classpath:" */
048: public static final String CLASSPATH_URL_PREFIX = "classpath:";
049:
050: /** Extension that indicates a Log4J XML config file: ".xml" */
051: public static final String XML_FILE_EXTENSION = ".xml";
052:
053: /**
054: * Initialize Log4J from the given file location, with no config file refreshing.
055: * Assumes an XML file in case of a ".xml" file extension, and a properties file else.
056: * @param location the location of the config file: either a "classpath:" location
057: * (e.g. "classpath:myLog4j.properties"), an absolute file URL
058: * (e.g. "file:C:/log4j.properties), or a plain absolute path in the file system
059: * (e.g. "C:/log4j.properties")
060: * @throws FileNotFoundException if the location specifies an invalid file path
061: */
062: public static void initLogging(String location)
063: throws FileNotFoundException {
064: String resolvedLocation = SystemPropertyUtils
065: .resolvePlaceholders(location);
066: URL url = ResourceUtils.getURL(resolvedLocation);
067: if (resolvedLocation.toLowerCase().endsWith(XML_FILE_EXTENSION)) {
068: DOMConfigurator.configure(url);
069: } else {
070: PropertyConfigurator.configure(url);
071: }
072: }
073:
074: /**
075: * Initialize Log4J from the given location, with the given refresh interval
076: * for the config file. Assumes an XML file in case of a ".xml" file extension,
077: * and a properties file else.
078: * <p>Log4J's watchdog thread will asynchronously check whether the timestamp
079: * of the config file has changed, using the given interval between checks.
080: * A refresh interval of 1000 milliseconds (one second), which allows to
081: * do on-demand log level changes with immediate effect, is not unfeasible.
082: * <p><b>WARNING:</b> Log4J's watchdog thread does not terminate until VM shutdown;
083: * in particular, it does not terminate on LogManager shutdown. Therefore, it is
084: * recommended to <i>not</i> use config file refreshing in a production J2EE
085: * environment; the watchdog thread would not stop on application shutdown there.
086: * @param location the location of the config file: either a "classpath:" location
087: * (e.g. "classpath:myLog4j.properties"), an absolute file URL
088: * (e.g. "file:C:/log4j.properties), or a plain absolute path in the file system
089: * (e.g. "C:/log4j.properties")
090: * @param refreshInterval interval between config file refresh checks, in milliseconds
091: * @throws FileNotFoundException if the location specifies an invalid file path
092: */
093: public static void initLogging(String location, long refreshInterval)
094: throws FileNotFoundException {
095: String resolvedLocation = SystemPropertyUtils
096: .resolvePlaceholders(location);
097: File file = ResourceUtils.getFile(resolvedLocation);
098: if (!file.exists()) {
099: throw new FileNotFoundException("Log4J config file ["
100: + resolvedLocation + "] not found");
101: }
102: if (resolvedLocation.toLowerCase().endsWith(XML_FILE_EXTENSION)) {
103: DOMConfigurator.configureAndWatch(file.getAbsolutePath(),
104: refreshInterval);
105: } else {
106: PropertyConfigurator.configureAndWatch(file
107: .getAbsolutePath(), refreshInterval);
108: }
109: }
110:
111: /**
112: * Shut down Log4J, properly releasing all file locks.
113: * <p>This isn't strictly necessary, but recommended for shutting down
114: * Log4J in a scenario where the host VM stays alive (for example, when
115: * shutting down an application in a J2EE environment).
116: */
117: public static void shutdownLogging() {
118: LogManager.shutdown();
119: }
120:
121: /**
122: * Set the specified system property to the current working directory.
123: * <p>This can be used e.g. for test environments, for applications that leverage
124: * Log4jWebConfigurer's "webAppRootKey" support in a web environment.
125: * @param key system property key to use, as expected in Log4j configuration
126: * (for example: "demo.root", used as "${demo.root}/WEB-INF/demo.log")
127: * @see org.springframework.web.util.Log4jWebConfigurer
128: */
129: public static void setWorkingDirSystemProperty(String key) {
130: System.setProperty(key, new File("").getAbsolutePath());
131: }
132:
133: }
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