Source Code for Apache Log4j Core Implementation
Apache Log4j Core Implementation
provides the functional components of the logging system. Users are free to
create their own plugins and include them in the logging configuration.
Apache Log4j Core is a required module to use Apache Log4j.
Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.
Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.
You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.
✍: FYIcenter.com
⏎ org/apache/logging/log4j/core/lookup/StrSubstitutor.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.core.lookup;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.ConfigurationAware;
import org.apache.logging.log4j.util.Strings;
/**
* Substitutes variables within a string by values.
* <p>
* This class takes a piece of text and substitutes all the variables within it.
* The default definition of a variable is <code>${variableName}</code>.
* The prefix and suffix can be changed via constructors and set methods.
* </p>
* <p>
* Variable values are typically resolved from a map, but could also be resolved
* from system properties, or by supplying a custom variable resolver.
* </p>
* <p>
* The simplest example is to use this class to replace Java System properties. For example:
* </p>
* <pre>
* StrSubstitutor.replaceSystemProperties(
* "You are running with java.version = ${java.version} and os.name = ${os.name}.");
* </pre>
* <p>
* Typical usage of this class follows the following pattern: First an instance is created
* and initialized with the map that contains the values for the available variables.
* If a prefix and/or suffix for variables should be used other than the default ones,
* the appropriate settings can be performed. After that the <code>replace()</code>
* method can be called passing in the source text for interpolation. In the returned
* text all variable references (as long as their values are known) will be resolved.
* The following example demonstrates this:
* </p>
* <pre>
* Map valuesMap = HashMap();
* valuesMap.put("animal", "quick brown fox");
* valuesMap.put("target", "lazy dog");
* String templateString = "The ${animal} jumped over the ${target}.";
* StrSubstitutor sub = new StrSubstitutor(valuesMap);
* String resolvedString = sub.replace(templateString);
* </pre>
* <p>yielding:</p>
* <pre>
* The quick brown fox jumped over the lazy dog.
* </pre>
* <p>
* Also, this class allows to set a default value for unresolved variables.
* The default value for a variable can be appended to the variable name after the variable
* default value delimiter. The default value of the variable default value delimiter is ':-',
* as in bash and other *nix shells, as those are arguably where the default ${} delimiter set originated.
* The variable default value delimiter can be manually set by calling {@link #setValueDelimiterMatcher(StrMatcher)},
* {@link #setValueDelimiter(char)} or {@link #setValueDelimiter(String)}.
* The following shows an example with variable default value settings:
* </p>
* <pre>
* Map valuesMap = HashMap();
* valuesMap.put("animal", "quick brown fox");
* valuesMap.put("target", "lazy dog");
* String templateString = "The ${animal} jumped over the ${target}. ${undefined.number:-1234567890}.";
* StrSubstitutor sub = new StrSubstitutor(valuesMap);
* String resolvedString = sub.replace(templateString);
* </pre>
* <p>yielding:</p>
* <pre>
* The quick brown fox jumped over the lazy dog. 1234567890.
* </pre>
* <p>
* In addition to this usage pattern there are some static convenience methods that
* cover the most common use cases. These methods can be used without the need of
* manually creating an instance. However if multiple replace operations are to be
* performed, creating and reusing an instance of this class will be more efficient.
* </p>
* <p>
* Variable replacement works in a recursive way. Thus, if a variable value contains
* a variable then that variable will also be replaced. Cyclic replacements are
* detected and will cause an exception to be thrown.
* </p>
* <p>
* Sometimes the interpolation's result must contain a variable prefix. As an example
* take the following source text:
* </p>
* <pre>
* The variable ${${name}} must be used.
* </pre>
* <p>
* Here only the variable's name referred to in the text should be replaced resulting
* in the text (assuming that the value of the <code>name</code> variable is <code>x</code>):
* </p>
* <pre>
* The variable ${x} must be used.
* </pre>
* <p>
* To achieve this effect there are two possibilities: Either set a different prefix
* and suffix for variables which do not conflict with the result text you want to
* produce. The other possibility is to use the escape character, by default '$'.
* If this character is placed before a variable reference, this reference is ignored
* and won't be replaced. For example:
* </p>
* <pre>
* The variable $${${name}} must be used.
* </pre>
* <p>
* In some complex scenarios you might even want to perform substitution in the
* names of variables, for instance
* </p>
* <pre>
* ${jre-${java.specification.version}}
* </pre>
* <p>
* <code>StrSubstitutor</code> supports this recursive substitution in variable
* names, but it has to be enabled explicitly by setting the
* {@link #setEnableSubstitutionInVariables(boolean) enableSubstitutionInVariables}
* property to <b>true</b>.
* </p>
*/
public class StrSubstitutor implements ConfigurationAware {
/**
* Constant for the default escape character.
*/
public static final char DEFAULT_ESCAPE = '$';
/**
* Constant for the default variable prefix.
*/
public static final StrMatcher DEFAULT_PREFIX = StrMatcher.stringMatcher(DEFAULT_ESCAPE + "{");
/**
* Constant for the default variable suffix.
*/
public static final StrMatcher DEFAULT_SUFFIX = StrMatcher.stringMatcher("}");
/**
* Constant for the default value delimiter of a variable.
*/
public static final String DEFAULT_VALUE_DELIMITER_STRING = ":-";
public static final StrMatcher DEFAULT_VALUE_DELIMITER = StrMatcher.stringMatcher(DEFAULT_VALUE_DELIMITER_STRING);
public static final String ESCAPE_DELIMITER_STRING = ":\\-";
public static final StrMatcher DEFAULT_VALUE_ESCAPE_DELIMITER = StrMatcher.stringMatcher(ESCAPE_DELIMITER_STRING);
private static final int BUF_SIZE = 256;
/**
* Stores the escape character.
*/
private char escapeChar;
/**
* Stores the variable prefix.
*/
private StrMatcher prefixMatcher;
/**
* Stores the variable suffix.
*/
private StrMatcher suffixMatcher;
/**
* Stores the default variable value delimiter
*/
private String valueDelimiterString;
private StrMatcher valueDelimiterMatcher;
/**
* Escape string to avoid matching the value delimiter matcher;
*/
private StrMatcher valueEscapeDelimiterMatcher;
/**
* Variable resolution is delegated to an implementer of VariableResolver.
*/
private StrLookup variableResolver;
/**
* The flag whether substitution in variable names is enabled.
*/
private boolean enableSubstitutionInVariables = true;
/**
* The currently active Configuration for use by ConfigurationAware StrLookup implementations.
*/
private Configuration configuration;
//-----------------------------------------------------------------------
/**
* Creates a new instance with defaults for variable prefix and suffix
* and the escaping character.
*/
public StrSubstitutor() {
this(null, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
}
/**
* Creates a new instance and initializes it. Uses defaults for variable
* prefix and suffix and the escaping character.
*
* @param valueMap the map with the variables' values, may be null
*/
public StrSubstitutor(final Map<String, String> valueMap) {
this(new MapLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
}
/**
* Creates a new instance and initializes it. Uses a default escaping character.
*
* @param valueMap the map with the variables' values, may be null
* @param prefix the prefix for variables, not null
* @param suffix the suffix for variables, not null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final Map<String, String> valueMap, final String prefix, final String suffix) {
this(new MapLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE);
}
/**
* Creates a new instance and initializes it.
*
* @param valueMap the map with the variables' values, may be null
* @param prefix the prefix for variables, not null
* @param suffix the suffix for variables, not null
* @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final Map<String, String> valueMap, final String prefix, final String suffix,
final char escape) {
this(new MapLookup(valueMap), prefix, suffix, escape);
}
/**
* Creates a new instance and initializes it.
*
* @param valueMap the map with the variables' values, may be null
* @param prefix the prefix for variables, not null
* @param suffix the suffix for variables, not null
* @param escape the escape character
* @param valueDelimiter the variable default value delimiter, may be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final Map<String, String> valueMap, final String prefix, final String suffix,
final char escape, final String valueDelimiter) {
this(new MapLookup(valueMap), prefix, suffix, escape, valueDelimiter);
}
/**
* Creates a new instance and initializes it. Uses defaults for variable
* prefix and suffix and the escaping character.
*
* @param properties the map with the variables' values, may be null
*/
public StrSubstitutor(final Properties properties) {
this(toTypeSafeMap(properties));
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
*/
public StrSubstitutor(final StrLookup variableResolver) {
this(variableResolver, DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
* @param prefix the prefix for variables, not null
* @param suffix the suffix for variables, not null
* @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final StrLookup variableResolver, final String prefix, final String suffix,
final char escape) {
this.setVariableResolver(variableResolver);
this.setVariablePrefix(prefix);
this.setVariableSuffix(suffix);
this.setEscapeChar(escape);
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
* @param prefix the prefix for variables, not null
* @param suffix the suffix for variables, not null
* @param escape the escape character
* @param valueDelimiter the variable default value delimiter string, may be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final StrLookup variableResolver, final String prefix, final String suffix, final char escape, final String valueDelimiter) {
this.setVariableResolver(variableResolver);
this.setVariablePrefix(prefix);
this.setVariableSuffix(suffix);
this.setEscapeChar(escape);
this.setValueDelimiter(valueDelimiter);
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
* @param prefixMatcher the prefix for variables, not null
* @param suffixMatcher the suffix for variables, not null
* @param escape the escape character
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final StrLookup variableResolver, final StrMatcher prefixMatcher,
final StrMatcher suffixMatcher,
final char escape) {
this(variableResolver, prefixMatcher, suffixMatcher, escape, DEFAULT_VALUE_DELIMITER,
DEFAULT_VALUE_ESCAPE_DELIMITER);
this.valueDelimiterString = DEFAULT_VALUE_DELIMITER_STRING;
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
* @param prefixMatcher the prefix for variables, not null
* @param suffixMatcher the suffix for variables, not null
* @param escape the escape character
* @param valueDelimiterMatcher the variable default value delimiter matcher, may be null
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final StrLookup variableResolver, final StrMatcher prefixMatcher,
final StrMatcher suffixMatcher, final char escape, final StrMatcher valueDelimiterMatcher) {
this.setVariableResolver(variableResolver);
this.setVariablePrefixMatcher(prefixMatcher);
this.setVariableSuffixMatcher(suffixMatcher);
this.setEscapeChar(escape);
this.setValueDelimiterMatcher(valueDelimiterMatcher);
}
/**
* Creates a new instance and initializes it.
*
* @param variableResolver the variable resolver, may be null
* @param prefixMatcher the prefix for variables, not null
* @param suffixMatcher the suffix for variables, not null
* @param escape the escape character
* @param valueDelimiterMatcher the variable default value delimiter matcher, may be null
* @param valueEscapeMatcher the matcher to escape defaulting, may be null.
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public StrSubstitutor(final StrLookup variableResolver, final StrMatcher prefixMatcher,
final StrMatcher suffixMatcher, final char escape, final StrMatcher valueDelimiterMatcher,
final StrMatcher valueEscapeMatcher) {
this.setVariableResolver(variableResolver);
this.setVariablePrefixMatcher(prefixMatcher);
this.setVariableSuffixMatcher(suffixMatcher);
this.setEscapeChar(escape);
this.setValueDelimiterMatcher(valueDelimiterMatcher);
valueEscapeDelimiterMatcher = valueEscapeMatcher;
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables in the given source object with
* their matching values from the map.
*
* @param source the source text containing the variables to substitute, null returns null
* @param valueMap the map with the values, may be null
* @return the result of the replace operation
*/
public static String replace(final Object source, final Map<String, String> valueMap) {
return new StrSubstitutor(valueMap).replace(source);
}
/**
* Replaces all the occurrences of variables in the given source object with
* their matching values from the map. This method allows to specify a
* custom variable prefix and suffix
*
* @param source the source text containing the variables to substitute, null returns null
* @param valueMap the map with the values, may be null
* @param prefix the prefix of variables, not null
* @param suffix the suffix of variables, not null
* @return the result of the replace operation
* @throws IllegalArgumentException if the prefix or suffix is null
*/
public static String replace(final Object source, final Map<String, String> valueMap, final String prefix,
final String suffix) {
return new StrSubstitutor(valueMap, prefix, suffix).replace(source);
}
/**
* Replaces all the occurrences of variables in the given source object with their matching
* values from the properties.
*
* @param source the source text containing the variables to substitute, null returns null
* @param valueProperties the properties with values, may be null
* @return the result of the replace operation
*/
public static String replace(final Object source, final Properties valueProperties) {
if (valueProperties == null) {
return source.toString();
}
final Map<String, String> valueMap = new HashMap<>();
final Enumeration<?> propNames = valueProperties.propertyNames();
while (propNames.hasMoreElements()) {
final String propName = (String) propNames.nextElement();
final String propValue = valueProperties.getProperty(propName);
valueMap.put(propName, propValue);
}
return StrSubstitutor.replace(source, valueMap);
}
private static Map<String, String> toTypeSafeMap(final Properties properties) {
final Map<String, String> map = new HashMap<>(properties.size());
for (final String name : properties.stringPropertyNames()) {
map.put(name, properties.getProperty(name));
}
return map;
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source string as a template.
*
* @param source the string to replace in, null returns null
* @return the result of the replace operation
*/
public String replace(final String source) {
return replace(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source string as a template.
*
* @param event The current LogEvent if there is one.
* @param source the string to replace in, null returns null
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final String source) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(source);
if (!substitute(event, buf, 0, source.length())) {
return source;
}
return buf.toString();
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source string as a template.
* <p>
* Only the specified portion of the string will be processed.
* The rest of the string is not processed, and is not returned.
* </p>
*
* @param source the string to replace in, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final String source, final int offset, final int length) {
return replace(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source string as a template.
* <p>
* Only the specified portion of the string will be processed.
* The rest of the string is not processed, and is not returned.
* </p>
*
* @param event the current LogEvent, if one exists.
* @param source the string to replace in, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final String source, final int offset, final int length) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(length).append(source, offset, length);
if (!substitute(event, buf, 0, length)) {
return source.substring(offset, offset + length);
}
return buf.toString();
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source array as a template.
* The array is not altered by this method.
*
* @param source the character array to replace in, not altered, null returns null
* @return the result of the replace operation
*/
public String replace(final char[] source) {
return replace(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source array as a template.
* The array is not altered by this method.
*
* @param event the current LogEvent, if one exists.
* @param source the character array to replace in, not altered, null returns null
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final char[] source) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(source.length).append(source);
substitute(event, buf, 0, source.length);
return buf.toString();
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source array as a template.
* The array is not altered by this method.
* <p>
* Only the specified portion of the array will be processed.
* The rest of the array is not processed, and is not returned.
* </p>
*
* @param source the character array to replace in, not altered, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final char[] source, final int offset, final int length) {
return replace(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source array as a template.
* The array is not altered by this method.
* <p>
* Only the specified portion of the array will be processed.
* The rest of the array is not processed, and is not returned.
* </p>
*
* @param event the current LogEvent, if one exists.
* @param source the character array to replace in, not altered, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final char[] source, final int offset, final int length) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(length).append(source, offset, length);
substitute(event, buf, 0, length);
return buf.toString();
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source buffer as a template.
* The buffer is not altered by this method.
*
* @param source the buffer to use as a template, not changed, null returns null
* @return the result of the replace operation
*/
public String replace(final StringBuffer source) {
return replace(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source buffer as a template.
* The buffer is not altered by this method.
*
* @param event the current LogEvent, if one exists.
* @param source the buffer to use as a template, not changed, null returns null
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final StringBuffer source) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(source.length()).append(source);
substitute(event, buf, 0, buf.length());
return buf.toString();
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source buffer as a template.
* The buffer is not altered by this method.
* <p>
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, and is not returned.
* </p>
*
* @param source the buffer to use as a template, not changed, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final StringBuffer source, final int offset, final int length) {
return replace(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source buffer as a template.
* The buffer is not altered by this method.
* <p>
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, and is not returned.
* </p>
*
* @param event the current LogEvent, if one exists.
* @param source the buffer to use as a template, not changed, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final StringBuffer source, final int offset, final int length) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(length).append(source, offset, length);
substitute(event, buf, 0, length);
return buf.toString();
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source builder as a template.
* The builder is not altered by this method.
*
* @param source the builder to use as a template, not changed, null returns null
* @return the result of the replace operation
*/
public String replace(final StringBuilder source) {
return replace(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source builder as a template.
* The builder is not altered by this method.
*
* @param event The LogEvent.
* @param source the builder to use as a template, not changed, null returns null.
* @return the result of the replace operation.
*/
public String replace(final LogEvent event, final StringBuilder source) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(source.length()).append(source);
substitute(event, buf, 0, buf.length());
return buf.toString();
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source builder as a template.
* The builder is not altered by this method.
* <p>
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, and is not returned.
* </p>
*
* @param source the builder to use as a template, not changed, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final StringBuilder source, final int offset, final int length) {
return replace(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source builder as a template.
* The builder is not altered by this method.
* <p>
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, and is not returned.
* </p>
*
* @param event the current LogEvent, if one exists.
* @param source the builder to use as a template, not changed, null returns null
* @param offset the start offset within the array, must be valid
* @param length the length within the array to be processed, must be valid
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final StringBuilder source, final int offset, final int length) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder(length).append(source, offset, length);
substitute(event, buf, 0, length);
return buf.toString();
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables in the given source object with
* their matching values from the resolver. The input source object is
* converted to a string using <code>toString</code> and is not altered.
*
* @param source the source to replace in, null returns null
* @return the result of the replace operation
*/
public String replace(final Object source) {
return replace(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables in the given source object with
* their matching values from the resolver. The input source object is
* converted to a string using <code>toString</code> and is not altered.
*
* @param event the current LogEvent, if one exists.
* @param source the source to replace in, null returns null
* @return the result of the replace operation
*/
public String replace(final LogEvent event, final Object source) {
if (source == null) {
return null;
}
final StringBuilder buf = new StringBuilder().append(source);
substitute(event, buf, 0, buf.length());
return buf.toString();
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables within the given source buffer
* with their matching values from the resolver.
* The buffer is updated with the result.
*
* @param source the buffer to replace in, updated, null returns zero
* @return true if altered
*/
public boolean replaceIn(final StringBuffer source) {
if (source == null) {
return false;
}
return replaceIn(source, 0, source.length());
}
/**
* Replaces all the occurrences of variables within the given source buffer
* with their matching values from the resolver.
* The buffer is updated with the result.
* <p>
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, but it is not deleted.
* </p>
*
* @param source the buffer to replace in, updated, null returns zero
* @param offset the start offset within the array, must be valid
* @param length the length within the buffer to be processed, must be valid
* @return true if altered
*/
public boolean replaceIn(final StringBuffer source, final int offset, final int length) {
return replaceIn(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables within the given source buffer
* with their matching values from the resolver.
* The buffer is updated with the result.
* <p>
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, but it is not deleted.
* </p>
*
* @param event the current LogEvent, if one exists.
* @param source the buffer to replace in, updated, null returns zero
* @param offset the start offset within the array, must be valid
* @param length the length within the buffer to be processed, must be valid
* @return true if altered
*/
public boolean replaceIn(final LogEvent event, final StringBuffer source, final int offset, final int length) {
if (source == null) {
return false;
}
final StringBuilder buf = new StringBuilder(length).append(source, offset, length);
if (!substitute(event, buf, 0, length)) {
return false;
}
source.replace(offset, offset + length, buf.toString());
return true;
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables within the given source
* builder with their matching values from the resolver.
*
* @param source the builder to replace in, updated, null returns zero
* @return true if altered
*/
public boolean replaceIn(final StringBuilder source) {
return replaceIn(null, source);
}
//-----------------------------------------------------------------------
/**
* Replaces all the occurrences of variables within the given source
* builder with their matching values from the resolver.
*
* @param event the current LogEvent, if one exists.
* @param source the builder to replace in, updated, null returns zero
* @return true if altered
*/
public boolean replaceIn(final LogEvent event, final StringBuilder source) {
if (source == null) {
return false;
}
return substitute(event, source, 0, source.length());
}
/**
* Replaces all the occurrences of variables within the given source
* builder with their matching values from the resolver.
* <p>
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, but it is not deleted.
* </p>
*
* @param source the builder to replace in, null returns zero
* @param offset the start offset within the array, must be valid
* @param length the length within the builder to be processed, must be valid
* @return true if altered
*/
public boolean replaceIn(final StringBuilder source, final int offset, final int length) {
return replaceIn(null, source, offset, length);
}
/**
* Replaces all the occurrences of variables within the given source
* builder with their matching values from the resolver.
* <p>
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, but it is not deleted.
* </p>
*
* @param event the current LogEvent, if one is present.
* @param source the builder to replace in, null returns zero
* @param offset the start offset within the array, must be valid
* @param length the length within the builder to be processed, must be valid
* @return true if altered
*/
public boolean replaceIn(final LogEvent event, final StringBuilder source, final int offset, final int length) {
if (source == null) {
return false;
}
return substitute(event, source, offset, length);
}
//-----------------------------------------------------------------------
/**
* Internal method that substitutes the variables.
* <p>
* Most users of this class do not need to call this method. This method will
* be called automatically by another (public) method.
* </p>
* <p>
* Writers of subclasses can override this method if they need access to
* the substitution process at the start or end.
* </p>
*
* @param event The current LogEvent, if there is one.
* @param buf the string builder to substitute into, not null
* @param offset the start offset within the builder, must be valid
* @param length the length within the builder to be processed, must be valid
* @return true if altered
*/
protected boolean substitute(final LogEvent event, final StringBuilder buf, final int offset, final int length) {
return substitute(event, buf, offset, length, null) > 0;
}
/**
* Recursive handler for multiple levels of interpolation. This is the main
* interpolation method, which resolves the values of all variable references
* contained in the passed in text.
*
* @param event The current LogEvent, if there is one.
* @param buf the string builder to substitute into, not null
* @param offset the start offset within the builder, must be valid
* @param length the length within the builder to be processed, must be valid
* @param priorVariables the stack keeping track of the replaced variables, may be null
* @return the length change that occurs, unless priorVariables is null when the int
* represents a boolean flag as to whether any change occurred.
*/
private int substitute(final LogEvent event, final StringBuilder buf, final int offset, final int length,
List<String> priorVariables) {
final StrMatcher prefixMatcher = getVariablePrefixMatcher();
final StrMatcher suffixMatcher = getVariableSuffixMatcher();
final char escape = getEscapeChar();
final StrMatcher valueDelimiterMatcher = getValueDelimiterMatcher();
final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables();
final boolean top = priorVariables == null;
boolean altered = false;
int lengthChange = 0;
char[] chars = getChars(buf);
int bufEnd = offset + length;
int pos = offset;
while (pos < bufEnd) {
final int startMatchLen = prefixMatcher.isMatch(chars, pos, offset, bufEnd);
if (startMatchLen == 0) {
pos++;
} else // found variable start marker
if (pos > offset && chars[pos - 1] == escape) {
// escaped
buf.deleteCharAt(pos - 1);
chars = getChars(buf);
lengthChange--;
altered = true;
bufEnd--;
} else {
// find suffix
final int startPos = pos;
pos += startMatchLen;
int endMatchLen = 0;
int nestedVarCount = 0;
while (pos < bufEnd) {
if (substitutionInVariablesEnabled
&& (endMatchLen = prefixMatcher.isMatch(chars, pos, offset, bufEnd)) != 0) {
// found a nested variable start
nestedVarCount++;
pos += endMatchLen;
continue;
}
endMatchLen = suffixMatcher.isMatch(chars, pos, offset, bufEnd);
if (endMatchLen == 0) {
pos++;
} else {
// found variable end marker
if (nestedVarCount == 0) {
String varNameExpr = new String(chars, startPos + startMatchLen, pos - startPos - startMatchLen);
if (substitutionInVariablesEnabled) {
final StringBuilder bufName = new StringBuilder(varNameExpr);
substitute(event, bufName, 0, bufName.length());
varNameExpr = bufName.toString();
}
pos += endMatchLen;
final int endPos = pos;
String varName = varNameExpr;
String varDefaultValue = null;
if (valueDelimiterMatcher != null) {
final char [] varNameExprChars = varNameExpr.toCharArray();
int valueDelimiterMatchLen = 0;
for (int i = 0; i < varNameExprChars.length; i++) {
// if there's any nested variable when nested variable substitution disabled, then stop resolving name and default value.
if (!substitutionInVariablesEnabled
&& prefixMatcher.isMatch(varNameExprChars, i, i, varNameExprChars.length) != 0) {
break;
}
if (valueEscapeDelimiterMatcher != null) {
int matchLen = valueEscapeDelimiterMatcher.isMatch(varNameExprChars, i);
if (matchLen != 0) {
String varNamePrefix = varNameExpr.substring(0, i) + Interpolator.PREFIX_SEPARATOR;
varName = varNamePrefix + varNameExpr.substring(i + matchLen - 1);
for (int j = i + matchLen; j < varNameExprChars.length; ++j){
if ((valueDelimiterMatchLen = valueDelimiterMatcher.isMatch(varNameExprChars, j)) != 0) {
varName = varNamePrefix + varNameExpr.substring(i + matchLen, j);
varDefaultValue = varNameExpr.substring(j + valueDelimiterMatchLen);
break;
}
}
break;
} else if ((valueDelimiterMatchLen = valueDelimiterMatcher.isMatch(varNameExprChars, i)) != 0) {
varName = varNameExpr.substring(0, i);
varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen);
break;
}
} else if ((valueDelimiterMatchLen = valueDelimiterMatcher.isMatch(varNameExprChars, i)) != 0) {
varName = varNameExpr.substring(0, i);
varDefaultValue = varNameExpr.substring(i + valueDelimiterMatchLen);
break;
}
}
}
// on the first call initialize priorVariables
if (priorVariables == null) {
priorVariables = new ArrayList<>();
priorVariables.add(new String(chars, offset, length + lengthChange));
}
// handle cyclic substitution
checkCyclicSubstitution(varName, priorVariables);
priorVariables.add(varName);
// resolve the variable
String varValue = resolveVariable(event, varName, buf, startPos, endPos);
if (varValue == null) {
varValue = varDefaultValue;
}
if (varValue != null) {
// recursive replace
final int varLen = varValue.length();
buf.replace(startPos, endPos, varValue);
altered = true;
int change = substitute(event, buf, startPos, varLen, priorVariables);
change = change + (varLen - (endPos - startPos));
pos += change;
bufEnd += change;
lengthChange += change;
chars = getChars(buf); // in case buffer was altered
}
// remove variable from the cyclic stack
priorVariables.remove(priorVariables.size() - 1);
break;
}
nestedVarCount--;
pos += endMatchLen;
}
}
}
}
if (top) {
return altered ? 1 : 0;
}
return lengthChange;
}
/**
* Checks if the specified variable is already in the stack (list) of variables.
*
* @param varName the variable name to check
* @param priorVariables the list of prior variables
*/
private void checkCyclicSubstitution(final String varName, final List<String> priorVariables) {
if (!priorVariables.contains(varName)) {
return;
}
final StringBuilder buf = new StringBuilder(BUF_SIZE);
buf.append("Infinite loop in property interpolation of ");
buf.append(priorVariables.remove(0));
buf.append(": ");
appendWithSeparators(buf, priorVariables, "->");
throw new IllegalStateException(buf.toString());
}
/**
* Internal method that resolves the value of a variable.
* <p>
* Most users of this class do not need to call this method. This method is
* called automatically by the substitution process.
* </p>
* <p>
* Writers of subclasses can override this method if they need to alter
* how each substitution occurs. The method is passed the variable's name
* and must return the corresponding value. This implementation uses the
* {@link #getVariableResolver()} with the variable's name as the key.
* </p>
*
* @param event The LogEvent, if there is one.
* @param variableName the name of the variable, not null
* @param buf the buffer where the substitution is occurring, not null
* @param startPos the start position of the variable including the prefix, valid
* @param endPos the end position of the variable including the suffix, valid
* @return the variable's value or <b>null</b> if the variable is unknown
*/
protected String resolveVariable(final LogEvent event, final String variableName, final StringBuilder buf,
final int startPos, final int endPos) {
final StrLookup resolver = getVariableResolver();
if (resolver == null) {
return null;
}
return resolver.lookup(event, variableName);
}
// Escape
//-----------------------------------------------------------------------
/**
* Returns the escape character.
*
* @return the character used for escaping variable references
*/
public char getEscapeChar() {
return this.escapeChar;
}
/**
* Sets the escape character.
* If this character is placed before a variable reference in the source
* text, this variable will be ignored.
*
* @param escapeCharacter the escape character (0 for disabling escaping)
*/
public void setEscapeChar(final char escapeCharacter) {
this.escapeChar = escapeCharacter;
}
// Prefix
//-----------------------------------------------------------------------
/**
* Gets the variable prefix matcher currently in use.
* <p>
* The variable prefix is the character or characters that identify the
* start of a variable. This prefix is expressed in terms of a matcher
* allowing advanced prefix matches.
* </p>
*
* @return the prefix matcher in use
*/
public StrMatcher getVariablePrefixMatcher() {
return prefixMatcher;
}
/**
* Sets the variable prefix matcher currently in use.
* <p>
* The variable prefix is the character or characters that identify the
* start of a variable. This prefix is expressed in terms of a matcher
* allowing advanced prefix matches.
* </p>
*
* @param prefixMatcher the prefix matcher to use, null ignored
* @return this, to enable chaining
* @throws IllegalArgumentException if the prefix matcher is null
*/
public StrSubstitutor setVariablePrefixMatcher(final StrMatcher prefixMatcher) {
if (prefixMatcher == null) {
throw new IllegalArgumentException("Variable prefix matcher must not be null!");
}
this.prefixMatcher = prefixMatcher;
return this;
}
/**
* Sets the variable prefix to use.
* <p>
* The variable prefix is the character or characters that identify the
* start of a variable. This method allows a single character prefix to
* be easily set.
* </p>
*
* @param prefix the prefix character to use
* @return this, to enable chaining
*/
public StrSubstitutor setVariablePrefix(final char prefix) {
return setVariablePrefixMatcher(StrMatcher.charMatcher(prefix));
}
/**
* Sets the variable prefix to use.
* <p>
* The variable prefix is the character or characters that identify the
* start of a variable. This method allows a string prefix to be easily set.
* </p>
*
* @param prefix the prefix for variables, not null
* @return this, to enable chaining
* @throws IllegalArgumentException if the prefix is null
*/
public StrSubstitutor setVariablePrefix(final String prefix) {
if (prefix == null) {
throw new IllegalArgumentException("Variable prefix must not be null!");
}
return setVariablePrefixMatcher(StrMatcher.stringMatcher(prefix));
}
// Suffix
//-----------------------------------------------------------------------
/**
* Gets the variable suffix matcher currently in use.
* <p>
* The variable suffix is the character or characters that identify the
* end of a variable. This suffix is expressed in terms of a matcher
* allowing advanced suffix matches.
* </p>
*
* @return the suffix matcher in use
*/
public StrMatcher getVariableSuffixMatcher() {
return suffixMatcher;
}
/**
* Sets the variable suffix matcher currently in use.
* <p>
* The variable suffix is the character or characters that identify the
* end of a variable. This suffix is expressed in terms of a matcher
* allowing advanced suffix matches.
* </p>
*
* @param suffixMatcher the suffix matcher to use, null ignored
* @return this, to enable chaining
* @throws IllegalArgumentException if the suffix matcher is null
*/
public StrSubstitutor setVariableSuffixMatcher(final StrMatcher suffixMatcher) {
if (suffixMatcher == null) {
throw new IllegalArgumentException("Variable suffix matcher must not be null!");
}
this.suffixMatcher = suffixMatcher;
return this;
}
/**
* Sets the variable suffix to use.
* <p>
* The variable suffix is the character or characters that identify the
* end of a variable. This method allows a single character suffix to
* be easily set.
* </p>
*
* @param suffix the suffix character to use
* @return this, to enable chaining
*/
public StrSubstitutor setVariableSuffix(final char suffix) {
return setVariableSuffixMatcher(StrMatcher.charMatcher(suffix));
}
/**
* Sets the variable suffix to use.
* <p>
* The variable suffix is the character or characters that identify the
* end of a variable. This method allows a string suffix to be easily set.
* </p>
*
* @param suffix the suffix for variables, not null
* @return this, to enable chaining
* @throws IllegalArgumentException if the suffix is null
*/
public StrSubstitutor setVariableSuffix(final String suffix) {
if (suffix == null) {
throw new IllegalArgumentException("Variable suffix must not be null!");
}
return setVariableSuffixMatcher(StrMatcher.stringMatcher(suffix));
}
// Variable Default Value Delimiter
//-----------------------------------------------------------------------
/**
* Gets the variable default value delimiter matcher currently in use.
* <p>
* The variable default value delimiter is the character or characters that delimit the
* variable name and the variable default value. This delimiter is expressed in terms of a matcher
* allowing advanced variable default value delimiter matches.
* </p>
* <p>
* If it returns null, then the variable default value resolution is disabled.
* </p>
*
* @return the variable default value delimiter matcher in use, may be null
*/
public StrMatcher getValueDelimiterMatcher() {
return valueDelimiterMatcher;
}
/**
* Sets the variable default value delimiter matcher to use.
* <p>
* The variable default value delimiter is the character or characters that delimit the
* variable name and the variable default value. This delimiter is expressed in terms of a matcher
* allowing advanced variable default value delimiter matches.
* </p>
* <p>
* If the <code>valueDelimiterMatcher</code> is null, then the variable default value resolution
* becomes disabled.
* </p>
*
* @param valueDelimiterMatcher variable default value delimiter matcher to use, may be null
* @return this, to enable chaining
*/
public StrSubstitutor setValueDelimiterMatcher(final StrMatcher valueDelimiterMatcher) {
this.valueDelimiterMatcher = valueDelimiterMatcher;
return this;
}
/**
* Sets the variable default value delimiter to use.
* <p>
* The variable default value delimiter is the character or characters that delimit the
* variable name and the variable default value. This method allows a single character
* variable default value delimiter to be easily set.
* </p>
*
* @param valueDelimiter the variable default value delimiter character to use
* @return this, to enable chaining
*/
public StrSubstitutor setValueDelimiter(final char valueDelimiter) {
return setValueDelimiterMatcher(StrMatcher.charMatcher(valueDelimiter));
}
/**
* Sets the variable default value delimiter to use.
* <p>
* The variable default value delimiter is the character or characters that delimit the
* variable name and the variable default value. This method allows a string
* variable default value delimiter to be easily set.
* </p>
* <p>
* If the <code>valueDelimiter</code> is null or empty string, then the variable default
* value resolution becomes disabled.
* </p>
*
* @param valueDelimiter the variable default value delimiter string to use, may be null or empty
* @return this, to enable chaining
*/
public StrSubstitutor setValueDelimiter(final String valueDelimiter) {
if (Strings.isEmpty(valueDelimiter)) {
setValueDelimiterMatcher(null);
return this;
}
String escapeValue = valueDelimiter.substring(0, valueDelimiter.length() - 1) + "\\"
+ valueDelimiter.substring(valueDelimiter.length() - 1);
valueEscapeDelimiterMatcher = StrMatcher.stringMatcher(escapeValue);
return setValueDelimiterMatcher(StrMatcher.stringMatcher(valueDelimiter));
}
// Resolver
//-----------------------------------------------------------------------
/**
* Gets the VariableResolver that is used to lookup variables.
*
* @return the VariableResolver
*/
public StrLookup getVariableResolver() {
return this.variableResolver;
}
/**
* Sets the VariableResolver that is used to lookup variables.
*
* @param variableResolver the VariableResolver
*/
public void setVariableResolver(final StrLookup variableResolver) {
if (variableResolver instanceof ConfigurationAware && this.configuration != null) {
((ConfigurationAware) variableResolver).setConfiguration(this.configuration);
}
this.variableResolver = variableResolver;
}
// Substitution support in variable names
//-----------------------------------------------------------------------
/**
* Returns a flag whether substitution is done in variable names.
*
* @return the substitution in variable names flag
*/
public boolean isEnableSubstitutionInVariables() {
return enableSubstitutionInVariables;
}
/**
* Sets a flag whether substitution is done in variable names. If set to
* <b>true</b>, the names of variables can contain other variables which are
* processed first before the original variable is evaluated, e.g.
* <code>${jre-${java.version}}</code>. The default value is <b>true</b>.
*
* @param enableSubstitutionInVariables the new value of the flag
*/
public void setEnableSubstitutionInVariables(final boolean enableSubstitutionInVariables) {
this.enableSubstitutionInVariables = enableSubstitutionInVariables;
}
private char[] getChars(final StringBuilder sb) {
final char[] chars = new char[sb.length()];
sb.getChars(0, sb.length(), chars, 0);
return chars;
}
/**
* Appends a iterable placing separators between each value, but
* not before the first or after the last.
* Appending a null iterable will have no effect..
*
* @param sb StringBuilder that contains the String being constructed.
* @param iterable the iterable to append
* @param separator the separator to use, null means no separator
*/
public void appendWithSeparators(final StringBuilder sb, final Iterable<?> iterable, String separator) {
if (iterable != null) {
separator = separator == null ? Strings.EMPTY : separator;
final Iterator<?> it = iterable.iterator();
while (it.hasNext()) {
sb.append(it.next());
if (it.hasNext()) {
sb.append(separator);
}
}
}
}
@Override
public String toString() {
return "StrSubstitutor(" + variableResolver.toString() + ')';
}
@Override
public void setConfiguration(final Configuration configuration) {
this.configuration = configuration;
if (this.variableResolver instanceof ConfigurationAware) {
((ConfigurationAware) this.variableResolver).setConfiguration(this.configuration);
}
}
}
⏎ org/apache/logging/log4j/core/lookup/StrSubstitutor.java
Or download all of them as a single archive file:
File name: log4j-core-2.14.1-sources.jar File size: 1281358 bytes Release date: 2021-03-06 Download
⇒ Source Code for Apache Log4j JDK Logging Adapter
⇐ Source Code for Apache Log4j API
2015-11-03, 83545👍, 0💬
Related Topics:
