001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.util;
018
019import org.apache.logging.log4j.util.PropertiesUtil;
020
021/**
022 * Log4j Constants.
023 */
024public final class Constants {
025
026    /**
027     * Name of the system property to use to identify the LogEvent factory.
028     */
029    public static final String LOG4J_LOG_EVENT_FACTORY = "Log4jLogEventFactory";
030
031    /**
032     * Name of the system property to use to identify the ContextSelector Class.
033     */
034    public static final String LOG4J_CONTEXT_SELECTOR = "Log4jContextSelector";
035
036    /**
037     * Property name for the default status (internal log4j logging) level to use if not specified in configuration.
038     */
039    public static final String LOG4J_DEFAULT_STATUS_LEVEL = "Log4jDefaultStatusLevel";
040
041    /**
042     * JNDI context name string literal.
043     */
044    public static final String JNDI_CONTEXT_NAME = "java:comp/env/log4j/context-name";
045
046    /**
047     * Number of milliseconds in a second.
048     */
049    public static final int MILLIS_IN_SECONDS = 1000;
050
051    /**
052     * Supports user request LOG4J2-898 to have the option to format a message in the background thread.
053     */
054    public static final boolean FORMAT_MESSAGES_IN_BACKGROUND = PropertiesUtil.getProperties().getBooleanProperty(
055            "log4j.format.msg.async", false);
056
057    /**
058     * LOG4J2-2109 if {@code true}, MessagePatternConverter will always operate as though
059     * <pre>%m{nolookups}</pre> is configured.
060     *
061     * @since 2.10
062     */
063    public static final boolean FORMAT_MESSAGES_PATTERN_DISABLE_LOOKUPS = PropertiesUtil.getProperties().getBooleanProperty(
064            "log4j2.formatMsgNoLookups", false);
065
066    /**
067     * {@code true} if we think we are running in a web container, based on the boolean value of system property
068     * "log4j2.is.webapp", or (if this system property is not set) whether the  {@code javax.servlet.Servlet} class
069     * is present in the classpath.
070     */
071    public static final boolean IS_WEB_APP = org.apache.logging.log4j.util.Constants.IS_WEB_APP;
072
073    /**
074     * Kill switch for object pooling in ThreadLocals that enables much of the LOG4J2-1270 no-GC behaviour.
075     * <p>
076     * {@code True} for non-{@link #IS_WEB_APP web apps}, disable by setting system property
077     * "log4j2.enable.threadlocals" to "false".
078     *
079     * @since 2.6
080     */
081    public static final boolean ENABLE_THREADLOCALS = org.apache.logging.log4j.util.Constants.ENABLE_THREADLOCALS;
082
083    /**
084     * Kill switch for garbage-free Layout behaviour that encodes LogEvents directly into
085     * {@link org.apache.logging.log4j.core.layout.ByteBufferDestination}s without creating intermediate temporary
086     * Objects.
087     * <p>
088     * {@code True} by default iff all loggers are asynchronous because system property
089     * {@code Log4jContextSelector} is set to {@code org.apache.logging.log4j.core.async.AsyncLoggerContextSelector}.
090     * Disable by setting system property "log4j2.enable.direct.encoders" to "false".
091     *
092     * @since 2.6
093     */
094    public static final boolean ENABLE_DIRECT_ENCODERS = PropertiesUtil.getProperties().getBooleanProperty(
095            "log4j2.enable.direct.encoders", true); // enable GC-free text encoding by default
096            // the alternative is to enable GC-free encoding only by default only when using all-async loggers:
097            //AsyncLoggerContextSelector.class.getName().equals(PropertiesUtil.getProperties().getStringProperty(LOG4J_CONTEXT_SELECTOR)));
098
099    /**
100     * Initial StringBuilder size used in RingBuffer LogEvents to store the contents of reusable Messages.
101     * <p>
102     * The default value is {@value}, users can override with system property "log4j.initialReusableMsgSize".
103     * </p>
104     * @since 2.6
105     */
106    public static final int INITIAL_REUSABLE_MESSAGE_SIZE = size("log4j.initialReusableMsgSize", 128);
107
108    /**
109     * Maximum size of the StringBuilders used in RingBuffer LogEvents to store the contents of reusable Messages.
110     * After a large message has been delivered to the appenders, the StringBuilder is trimmed to this size.
111     * <p>
112     * The default value is {@value}, which allows the StringBuilder to resize three times from its initial size.
113     * Users can override with system property "log4j.maxReusableMsgSize".
114     * </p>
115     * @since 2.6
116     */
117    public static final int MAX_REUSABLE_MESSAGE_SIZE = size("log4j.maxReusableMsgSize", (128 * 2 + 2) * 2 + 2);
118
119    /**
120     * Size of CharBuffers used by text encoders.
121     * <p>
122     * The default value is {@value}, users can override with system property "log4j.encoder.charBufferSize".
123     * </p>
124     * @since 2.6
125     */
126    public static final int ENCODER_CHAR_BUFFER_SIZE = size("log4j.encoder.charBufferSize", 2048);
127
128    /**
129     * Default size of ByteBuffers used to encode LogEvents without allocating temporary objects.
130     * <p>
131     * The default value is {@value}, users can override with system property "log4j.encoder.byteBufferSize".
132     * </p>
133     * @see org.apache.logging.log4j.core.layout.ByteBufferDestination
134     * @since 2.6
135     */
136    public static final int ENCODER_BYTE_BUFFER_SIZE = size("log4j.encoder.byteBufferSize", 8 * 1024);
137
138
139    private static int size(final String property, final int defaultValue) {
140        return PropertiesUtil.getProperties().getIntegerProperty(property, defaultValue);
141    }
142
143    /**
144     * Prevent class instantiation.
145     */
146    private Constants() {
147    }
148}