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The Apache Log4j Implementation
/*
* 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.Objects;
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.status.StatusLogger;
import org.apache.logging.log4j.util.Strings;
/**
* Substitutes variables within a string by values.
*
* This class takes a piece of text and substitutes all the variables within it.
* The default definition of a variable is ${variableName}.
* The prefix and suffix can be changed via constructors and set methods.
*
*
* Variable values are typically resolved from a map, but could also be resolved
* from system properties, or by supplying a custom variable resolver.
*
*
* The simplest example is to use this class to replace Java System properties. For example:
*
*
* StrSubstitutor.replaceSystemProperties(
* "You are running with java.version = ${java.version} and os.name = ${os.name}.");
*
*
* 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 replace()
* 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:
*
*
* 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);
*
* yielding:
*
* The quick brown fox jumped over the lazy dog.
*
*
* 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:
*
*
* 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);
*
* yielding:
*
* The quick brown fox jumped over the lazy dog. 1234567890.
*
*
* 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.
*
*
* 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.
*
*
* Sometimes the interpolation's result must contain a variable prefix. As an example
* take the following source text:
*
*
* The variable ${${name}} must be used.
*
*
* Here only the variable's name referred to in the text should be replaced resulting
* in the text (assuming that the value of the name variable is x):
*
*
* The variable ${x} must be used.
*
*
* To achieve this effect there are two possibilities: Either set a different prefix
* and suffix for variables which do not conflict with the result text you want to
* produce. The other possibility is to use the escape character, by default '$'.
* If this character is placed before a variable reference, this reference is ignored
* and won't be replaced. For example:
*
*
* The variable $${${name}} must be used.
*
*
* In some complex scenarios you might even want to perform substitution in the
* names of variables, for instance
*
*
* ${jre-${java.specification.version}}
*
*
* StrSubstitutor supports this recursive substitution in variable
* names, but it has to be enabled explicitly by setting the
* {@link #setEnableSubstitutionInVariables(boolean) enableSubstitutionInVariables}
* property to true.
*
*/
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;
private boolean recursiveEvaluationAllowed;
//-----------------------------------------------------------------------
/**
* 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 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 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 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 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;
}
StrSubstitutor(final StrSubstitutor other) {
Objects.requireNonNull(other, "other");
this.setVariableResolver(other.getVariableResolver());
this.setVariablePrefixMatcher(other.getVariablePrefixMatcher());
this.setVariableSuffixMatcher(other.getVariableSuffixMatcher());
this.setEscapeChar(other.getEscapeChar());
this.setValueDelimiterMatcher(other.valueDelimiterMatcher);
this.valueEscapeDelimiterMatcher = other.valueEscapeDelimiterMatcher;
this.configuration = other.configuration;
this.recursiveEvaluationAllowed = other.isRecursiveEvaluationAllowed();
this.enableSubstitutionInVariables = other.isEnableSubstitutionInVariables();
this.valueDelimiterString = other.valueDelimiterString;
}
//-----------------------------------------------------------------------
/**
* 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 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 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 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 toTypeSafeMap(final Properties properties) {
final Map map = new HashMap<>(properties.size());
for (final String name : properties.stringPropertyNames()) {
map.put(name, properties.getProperty(name));
}
return map;
}
private static String handleFailedReplacement(String input, Throwable throwable) {
StatusLogger.getLogger().error("Replacement failed on {}", input, throwable);
return input;
}
//-----------------------------------------------------------------------
/**
* 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);
try {
if (!substitute(event, buf, 0, source.length())) {
return source;
}
} catch (Throwable t) {
return handleFailedReplacement(source, t);
}
return buf.toString();
}
/**
* Replaces all the occurrences of variables with their matching values
* from the resolver using the given source string as a template.
*
* Only the specified portion of the string will be processed.
* The rest of the string is not processed, and is not returned.
*
*
* @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.
*
* Only the specified portion of the string will be processed.
* The rest of the string is not processed, and is not returned.
*
*
* @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);
try {
if (!substitute(event, buf, 0, length)) {
return source.substring(offset, offset + length);
}
} catch (Throwable t) {
return handleFailedReplacement(source, t);
}
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);
try {
substitute(event, buf, 0, source.length);
} catch (Throwable t) {
return handleFailedReplacement(new String(source), t);
}
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.
*
* Only the specified portion of the array will be processed.
* The rest of the array is not processed, and is not returned.
*
*
* @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.
*
* Only the specified portion of the array will be processed.
* The rest of the array is not processed, and is not returned.
*
*
* @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);
try {
substitute(event, buf, 0, length);
} catch (Throwable t) {
return handleFailedReplacement(new String(source, offset, length), t);
}
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);
try {
substitute(event, buf, 0, buf.length());
} catch (Throwable t) {
return handleFailedReplacement(source.toString(), t);
}
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.
*
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, and is not returned.
*
*
* @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.
*
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, and is not returned.
*
*
* @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);
try {
substitute(event, buf, 0, length);
} catch (Throwable t) {
return handleFailedReplacement(source.substring(offset, offset + length), t);
}
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);
try {
substitute(event, buf, 0, buf.length());
} catch (Throwable t) {
return handleFailedReplacement(source.toString(), t);
}
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.
*
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, and is not returned.
*
*
* @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.
*
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, and is not returned.
*
*
* @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);
try {
substitute(event, buf, 0, length);
} catch (Throwable t) {
return handleFailedReplacement(source.substring(offset, offset + length), t);
}
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 toString 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 toString 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;
}
String stringValue = String.valueOf(source);
final StringBuilder buf = new StringBuilder(stringValue.length()).append(stringValue);
try {
substitute(event, buf, 0, buf.length());
} catch (Throwable t) {
return handleFailedReplacement(stringValue, t);
}
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.
*
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, but it is not deleted.
*
*
* @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.
*
* Only the specified portion of the buffer will be processed.
* The rest of the buffer is not processed, but it is not deleted.
*
*
* @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);
try {
if (!substitute(event, buf, 0, length)) {
return false;
}
} catch (Throwable t) {
StatusLogger.getLogger().error("Replacement failed on {}", source, t);
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.
*
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, but it is not deleted.
*
*
* @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.
*
* Only the specified portion of the builder will be processed.
* The rest of the builder is not processed, but it is not deleted.
*
*
* @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.
*
* Most users of this class do not need to call this method. This method will
* be called automatically by another (public) method.
*
*
* Writers of subclasses can override this method if they need access to
* the substitution process at the start or end.
*
*
* @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 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) {
// initialize priorVariables if they're not already set
if (priorVariables == null) {
priorVariables = new ArrayList<>();
}
final StringBuilder bufName = new StringBuilder(varNameExpr);
substitute(event, bufName, 0, bufName.length(), priorVariables);
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
boolean isCyclic = isCyclicSubstitution(varName, priorVariables);
// resolve the variable
String varValue = isCyclic ? null : 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 = isRecursiveEvaluationAllowed()
? substitute(event, buf, startPos, varLen, priorVariables)
: 0;
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
if (!isCyclic) {
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, adding the value
* if it's not already present.
*
* @param varName the variable name to check
* @param priorVariables the list of prior variables
* @return true if this is a cyclic substitution
*/
private boolean isCyclicSubstitution(final String varName, final List priorVariables) {
if (!priorVariables.contains(varName)) {
priorVariables.add(varName);
return false;
}
final StringBuilder buf = new StringBuilder(BUF_SIZE);
buf.append("Infinite loop in property interpolation of ");
appendWithSeparators(buf, priorVariables, "->");
StatusLogger.getLogger().warn(buf);
return true;
}
/**
* Internal method that resolves the value of a variable.
*
* Most users of this class do not need to call this method. This method is
* called automatically by the substitution process.
*
*
* 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.
*
*
* @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 null 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;
}
try {
return resolver.lookup(event, variableName);
} catch (Throwable t) {
StatusLogger.getLogger().error("Resolver failed to lookup {}", variableName, t);
return null;
}
}
// 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.
*
* 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.
*
*
* @return the prefix matcher in use
*/
public StrMatcher getVariablePrefixMatcher() {
return prefixMatcher;
}
/**
* Sets the variable prefix matcher currently in use.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* @return the suffix matcher in use
*/
public StrMatcher getVariableSuffixMatcher() {
return suffixMatcher;
}
/**
* Sets the variable suffix matcher currently in use.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* If it returns null, then the variable default value resolution is disabled.
*
*
* @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.
*
* 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.
*
*
* If the valueDelimiterMatcher is null, then the variable default value resolution
* becomes disabled.
*
*
* @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.
*
* 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.
*
*
* @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.
*
* 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.
*
*
* If the valueDelimiter is null or empty string, then the variable default
* value resolution becomes disabled.
*
*
* @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
* true, the names of variables can contain other variables which are
* processed first before the original variable is evaluated, e.g.
* ${jre-${java.version}}. The default value is true.
*
* @param enableSubstitutionInVariables the new value of the flag
*/
public void setEnableSubstitutionInVariables(final boolean enableSubstitutionInVariables) {
this.enableSubstitutionInVariables = enableSubstitutionInVariables;
}
boolean isRecursiveEvaluationAllowed() {
return recursiveEvaluationAllowed;
}
void setRecursiveEvaluationAllowed(final boolean recursiveEvaluationAllowed) {
this.recursiveEvaluationAllowed = recursiveEvaluationAllowed;
}
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);
}
}
}