Coverage Report

Coverage Report - org.apache.commons.lang3.text.StrSubstitutor

Classes in this File
Line Coverage
Branch Coverage
Complexity
StrSubstitutor
99%
201/203
97%
78/80
2.5
 /*
  * 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.commons.lang3.text;
 
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 
 /**
  * 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>
  * Variable values are typically resolved from a map, but could also be resolved
  * from system properties, or by supplying a custom variable resolver.
  * <p>
  * The simplest example is to use this class to replace Java System properties. For example:
  * <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:
  * <pre>
  * Map valuesMap = HashMap();
  * valuesMap.put(&quot;animal&quot;, &quot;quick brown fox&quot;);
  * valuesMap.put(&quot;target&quot;, &quot;lazy dog&quot;);
  * String templateString = &quot;The ${animal} jumped over the ${target}.&quot;;
  * StrSubstitutor sub = new StrSubstitutor(valuesMap);
  * String resolvedString = sub.replace(templateString);
  * </pre>
  * yielding:
  * <pre>
  *      The quick brown fox jumped over the lazy dog.
  * </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>
  * 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>
  * Sometimes the interpolation's result must contain a variable prefix. As an example
  * take the following source text:
  * <pre>
  *   The variable ${${name}} must be used.
  * </pre>
  * 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>):
  * <pre>
  *   The variable ${x} must be used.
  * </pre>
  * To achieve this effect there are two possibilities: Either set a different prefix
  * and suffix for variables which do not conflict with the result text you want to
  * produce. The other possibility is to use the escape character, by default '$'.
  * If this character is placed before a variable reference, this reference is ignored
  * and won't be replaced. For example:
  * <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
  * <pre>
  * ${jre-${java.specification.version}}
  * </pre>
  * <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>.
  *
  * @version $Id: StrSubstitutor.java 1436770 2013-01-22 07:09:45Z ggregory $
  * @since 2.2
  */
 public class StrSubstitutor {
 
     /**
      * Constant for the default escape character.
      */
     public static final char DEFAULT_ESCAPE = '$';
     /**
      * Constant for the default variable prefix.
      */
     public static final StrMatcher DEFAULT_PREFIX = StrMatcher.stringMatcher("${");
     /**
      * Constant for the default variable suffix.
      */
     public static final StrMatcher DEFAULT_SUFFIX = StrMatcher.stringMatcher("}");
 
     /**
      * Stores the escape character.
      */
     private char escapeChar;
     /**
      * Stores the variable prefix.
      */
     private StrMatcher prefixMatcher;
     /**
      * Stores the variable suffix.
      */
     private StrMatcher suffixMatcher;
     /**
      * Variable resolution is delegated to an implementor of VariableResolver.
      */
     private StrLookup<?> variableResolver;
     /**
      * The flag whether substitution in variable names is enabled.
      */
     private boolean enableSubstitutionInVariables;
 
     //-----------------------------------------------------------------------
     /**
      * Replaces all the occurrences of variables in the given source object with
      * their matching values from the map.
      *
      * @param <V> the type of the values in 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 <V> String replace(final Object source, final Map<String, V> 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 specifiy a
      * custom variable prefix and suffix
      *
      * @param <V> the type of the values in 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
      * @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 <V> String replace(final Object source, final Map<String, V> 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<String,String>();
         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);
     }
 
     /**
      * Replaces all the occurrences of variables in the given source object with
      * their matching values from the system properties.
      *
      * @param source  the source text containing the variables to substitute, null returns null
      * @return the result of the replace operation
      */
     public static String replaceSystemProperties(final Object source) {
         return new StrSubstitutor(StrLookup.systemPropertiesLookup()).replace(source);
     }
 
     //-----------------------------------------------------------------------
     /**
      * Creates a new instance with defaults for variable prefix and suffix
      * and the escaping character.
      */
     public StrSubstitutor() {
         this((StrLookup<?>) 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 <V> the type of the values in the map
      * @param valueMap  the map with the variables' values, may be null
      */
     public <V> StrSubstitutor(final Map<String, V> valueMap) {
         this(StrLookup.mapLookup(valueMap), DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ESCAPE);
     }
 
     /**
      * Creates a new instance and initializes it. Uses a default escaping character.
      *
      * @param <V> the type of the values in the map
      * @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 <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix) {
         this(StrLookup.mapLookup(valueMap), prefix, suffix, DEFAULT_ESCAPE);
     }
 
     /**
      * Creates a new instance and initializes it.
      *
      * @param <V> the type of the values in the map
      * @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 <V> StrSubstitutor(final Map<String, V> valueMap, final String prefix, final String suffix, final char escape) {
         this(StrLookup.mapLookup(valueMap), prefix, suffix, escape);
     }
 
     /**
      * 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 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.setVariableResolver(variableResolver);
         this.setVariablePrefixMatcher(prefixMatcher);
         this.setVariableSuffixMatcher(suffixMatcher);
         this.setEscapeChar(escape);
     }
 
     //-----------------------------------------------------------------------
     /**
      * 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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(source);
         if (substitute(buf, 0, source.length()) == false) {
             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.
      *
      * @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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
         if (substitute(buf, 0, length) == false) {
             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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(source.length).append(source);
         substitute(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.
      *
      * @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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
         substitute(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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(source.length()).append(source);
         substitute(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.
      *
      * @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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
         substitute(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 StrBuilder source) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(source.length()).append(source);
         substitute(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.
      *
      * @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 StrBuilder source, final int offset, final int length) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
         substitute(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) {
         if (source == null) {
             return null;
         }
         final StrBuilder buf = new StrBuilder().append(source);
         substitute(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.
      *
      * @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) {
         if (source == null) {
             return false;
         }
         final StrBuilder buf = new StrBuilder(length).append(source, offset, length);
         if (substitute(buf, 0, length) == false) {
             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 StrBuilder source) {
         if (source == null) {
             return false;
         }
         return substitute(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.
      *
      * @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 StrBuilder source, final int offset, final int length) {
         if (source == null) {
             return false;
         }
         return substitute(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>
      * Writers of subclasses can override this method if they need access to
      * the substitution process at the start or end.
      *
      * @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 StrBuilder buf, final int offset, final int length) {
         return substitute(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 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 StrBuilder buf, final int offset, final int length, List<String> priorVariables) {
         final StrMatcher prefixMatcher = getVariablePrefixMatcher();
         final StrMatcher suffixMatcher = getVariableSuffixMatcher();
         final char escape = getEscapeChar();
 
         final boolean top = priorVariables == null;
         boolean altered = false;
         int lengthChange = 0;
         char[] chars = buf.buffer;
         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 = buf.buffer; // in case buffer was altered
                     lengthChange--;
                     altered = true;
                     bufEnd--;
                 } else {
                     // find suffix
                     final int startPos = pos;
                     pos += startMatchLen;
                     int endMatchLen = 0;
                     int nestedVarCount = 0;
                     while (pos < bufEnd) {
                         if (isEnableSubstitutionInVariables()
                                 && (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 varName = new String(chars, startPos
                                         + startMatchLen, pos - startPos
                                         - startMatchLen);
                                 if (isEnableSubstitutionInVariables()) {
                                     final StrBuilder bufName = new StrBuilder(varName);
                                     substitute(bufName, 0, bufName.length());
                                     varName = bufName.toString();
                                 }
                                 pos += endMatchLen;
                                 final int endPos = pos;
 
                                 // on the first call initialize priorVariables
                                 if (priorVariables == null) {
                                     priorVariables = new ArrayList<String>();
                                     priorVariables.add(new String(chars,
                                             offset, length));
                                 }
 
                                 // handle cyclic substitution
                                 checkCyclicSubstitution(varName, priorVariables);
                                 priorVariables.add(varName);
 
                                 // resolve the variable
                                 final String varValue = resolveVariable(varName, buf,
                                         startPos, endPos);
                                 if (varValue != null) {
                                     // recursive replace
                                     final int varLen = varValue.length();
                                     buf.replace(startPos, endPos, varValue);
                                     altered = true;
                                     int change = substitute(buf, startPos,
                                             varLen, priorVariables);
                                     change = change
                                             + varLen - (endPos - startPos);
                                     pos += change;
                                     bufEnd += change;
                                     lengthChange += change;
                                     chars = buf.buffer; // in case buffer was
                                                         // altered
                                 }
 
                                 // remove variable from the cyclic stack
                                 priorVariables
                                         .remove(priorVariables.size() - 1);
                                 break;
                             } else {
                                 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) == false) {
             return;
         }
         final StrBuilder buf = new StrBuilder(256);
         buf.append("Infinite loop in property interpolation of ");
         buf.append(priorVariables.remove(0));
         buf.append(": ");
         buf.appendWithSeparators(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>
      * 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 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 String variableName, final StrBuilder buf, final int startPos, final int endPos) {
         final StrLookup<?> resolver = getVariableResolver();
         if (resolver == null) {
             return null;
         }
         return resolver.lookup(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 characer 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.
      * <p>
      * The variable prefix is the characer 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.
      * <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.
      *
      * @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 characer 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.
      * <p>
      * The variable suffix is the characer 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.
      * <p>
      * The variable suffix is the characer 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.
      * <p>
      * The variable suffix is the characer 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.
      * <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.
      *
      * @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));
     }
 
     // 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) {
         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
      * @since 3.0
      */
     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>false</b>.
      *
      * @param enableSubstitutionInVariables the new value of the flag
      * @since 3.0
      */
     public void setEnableSubstitutionInVariables(
             final boolean enableSubstitutionInVariables) {
         this.enableSubstitutionInVariables = enableSubstitutionInVariables;
     }
 }