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     * LOG4J2-3198 property which used to globally opt out of lookups in pattern layout message text, however
059     * this is the default and this property is no longer read.
060     *
061     * Deprecated in 2.15.
062     *
063     * @since 2.10
064     * @deprecated no longer used, lookups are only used when {@code %m{lookups}} is specified
065     */
066    @Deprecated
067    public static final boolean FORMAT_MESSAGES_PATTERN_DISABLE_LOOKUPS = PropertiesUtil.getProperties().getBooleanProperty(
068            "log4j2.formatMsgNoLookups", true);
069
070    /**
071     * {@code true} if we think we are running in a web container, based on the boolean value of system property
072     * "log4j2.is.webapp", or (if this system property is not set) whether the  {@code javax.servlet.Servlet} class
073     * is present in the classpath.
074     */
075    public static final boolean IS_WEB_APP = org.apache.logging.log4j.util.Constants.IS_WEB_APP;
076
077    /**
078     * Kill switch for object pooling in ThreadLocals that enables much of the LOG4J2-1270 no-GC behaviour.
079     * <p>
080     * {@code True} for non-{@link #IS_WEB_APP web apps}, disable by setting system property
081     * "log4j2.enable.threadlocals" to "false".
082     *
083     * @since 2.6
084     */
085    public static final boolean ENABLE_THREADLOCALS = org.apache.logging.log4j.util.Constants.ENABLE_THREADLOCALS;
086
087    /**
088     * Kill switch for garbage-free Layout behaviour that encodes LogEvents directly into
089     * {@link org.apache.logging.log4j.core.layout.ByteBufferDestination}s without creating intermediate temporary
090     * Objects.
091     * <p>
092     * {@code True} by default iff all loggers are asynchronous because system property
093     * {@code Log4jContextSelector} is set to {@code org.apache.logging.log4j.core.async.AsyncLoggerContextSelector}.
094     * Disable by setting system property "log4j2.enable.direct.encoders" to "false".
095     *
096     * @since 2.6
097     */
098    public static final boolean ENABLE_DIRECT_ENCODERS = PropertiesUtil.getProperties().getBooleanProperty(
099            "log4j2.enable.direct.encoders", true); // enable GC-free text encoding by default
100            // the alternative is to enable GC-free encoding only by default only when using all-async loggers:
101            //AsyncLoggerContextSelector.class.getName().equals(PropertiesUtil.getProperties().getStringProperty(LOG4J_CONTEXT_SELECTOR)));
102
103    /**
104     * Initial StringBuilder size used in RingBuffer LogEvents to store the contents of reusable Messages.
105     * <p>
106     * The default value is {@value}, users can override with system property "log4j.initialReusableMsgSize".
107     * </p>
108     * @since 2.6
109     */
110    public static final int INITIAL_REUSABLE_MESSAGE_SIZE = size("log4j.initialReusableMsgSize", 128);
111
112    /**
113     * Maximum size of the StringBuilders used in RingBuffer LogEvents to store the contents of reusable Messages.
114     * After a large message has been delivered to the appenders, the StringBuilder is trimmed to this size.
115     * <p>
116     * The default value is {@value}, which allows the StringBuilder to resize three times from its initial size.
117     * Users can override with system property "log4j.maxReusableMsgSize".
118     * </p>
119     * @since 2.6
120     */
121    public static final int MAX_REUSABLE_MESSAGE_SIZE = size("log4j.maxReusableMsgSize", (128 * 2 + 2) * 2 + 2);
122
123    /**
124     * Size of CharBuffers used by text encoders.
125     * <p>
126     * The default value is {@value}, users can override with system property "log4j.encoder.charBufferSize".
127     * </p>
128     * @since 2.6
129     */
130    public static final int ENCODER_CHAR_BUFFER_SIZE = size("log4j.encoder.charBufferSize", 2048);
131
132    /**
133     * Default size of ByteBuffers used to encode LogEvents without allocating temporary objects.
134     * <p>
135     * The default value is {@value}, users can override with system property "log4j.encoder.byteBufferSize".
136     * </p>
137     * @see org.apache.logging.log4j.core.layout.ByteBufferDestination
138     * @since 2.6
139     */
140    public static final int ENCODER_BYTE_BUFFER_SIZE = size("log4j.encoder.byteBufferSize", 8 * 1024);
141
142
143    private static int size(final String property, final int defaultValue) {
144        return PropertiesUtil.getProperties().getIntegerProperty(property, defaultValue);
145    }
146
147    /**
148     * Prevent class instantiation.
149     */
150    private Constants() {
151    }
152}