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 package org.apache.logging.log4j.core.impl;
18
19 import org.apache.logging.log4j.core.LoggerContext;
20 import org.apache.logging.log4j.core.helpers.Constants;
21 import org.apache.logging.log4j.core.helpers.Loader;
22 import org.apache.logging.log4j.core.selector.ClassLoaderContextSelector;
23 import org.apache.logging.log4j.core.selector.ContextSelector;
24 import org.apache.logging.log4j.status.StatusLogger;
25 import org.apache.logging.log4j.spi.LoggerContextFactory;
26
27 /**
28 * Factory to locate a ContextSelector and then load a LoggerContext.
29 */
30 public class Log4jContextFactory implements LoggerContextFactory {
31
32 private ContextSelector selector;
33
34 private StatusLogger logger = StatusLogger.getLogger();
35
36 private ThreadLocal<Log4jContextFactory> recursive = new ThreadLocal<Log4jContextFactory>();
37
38 /**
39 * Constructor that initializes the ContextSelector.
40 */
41 public Log4jContextFactory() {
42 String sel = System.getProperty(Constants.LOG4J_CONTEXT_SELECTOR);
43 if (sel != null) {
44 try {
45 Class clazz = Loader.loadClass(sel);
46 if (clazz != null && ContextSelector.class.isAssignableFrom(clazz)) {
47 selector = (ContextSelector) clazz.newInstance();
48 return;
49 }
50 } catch (Exception ex) {
51 logger.error("Unable to create context " + sel, ex);
52 }
53
54 }
55 selector = new ClassLoaderContextSelector();
56 }
57
58 /**
59 * Return the ContextSelector.
60 * @return The ContextSelector.
61 */
62 public ContextSelector getSelector() {
63 return selector;
64 }
65
66 /**
67 * Load the LoggerContext using the ContextSelector.
68 * @param fqcn The fully qualified class name of the caller.
69 * @param currentContext If true returns the current Context, if false returns the Context appropriate
70 * for the caller if a more appropriate Context can be determined.
71 * @return The LoggerContext.
72 */
73 public LoggerContext getContext(String fqcn, boolean currentContext) {
74 LoggerContext ctx = selector.getContext(fqcn, currentContext);
75 synchronized (ctx) {
76 if (recursive.get() != null || ctx.isStarted()) {
77 return ctx;
78 }
79 try {
80 recursive.set(this);
81 ctx.start();
82 return ctx;
83 } finally {
84 recursive.remove();
85 }
86 }
87 }
88 }