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From chtom...@apache.org
Subject [23/25] [text] chore: update packages back to org.apache.commons.text.*
Date Fri, 10 Feb 2017 13:17:36 GMT
http://git-wip-us.apache.org/repos/asf/commons-text/blob/c7cf533d/src/main/java/org/apache/commons/text/StrLookup.java
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diff --git a/src/main/java/org/apache/commons/text/StrLookup.java b/src/main/java/org/apache/commons/text/StrLookup.java
new file mode 100644
index 0000000..f9bffb5
--- /dev/null
+++ b/src/main/java/org/apache/commons/text/StrLookup.java
@@ -0,0 +1,180 @@
+/*
+ * 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.text;
+
+import java.util.Map;
+
+/**
+ * Lookup a String key to a String value.
+ * <p>
+ * This class represents the simplest form of a string to string map.
+ * It has a benefit over a map in that it can create the result on
+ * demand based on the key.
+ * <p>
+ * This class comes complete with various factory methods.
+ * If these do not suffice, you can subclass and implement your own matcher.
+ * <p>
+ * For example, it would be possible to implement a lookup that used the
+ * key as a primary key, and looked up the value on demand from the database
+ *
+ * @since 1.0
+ */
+public abstract class StrLookup<V> {
+
+    /**
+     * Lookup that always returns null.
+     */
+    private static final StrLookup<String> NONE_LOOKUP = new MapStrLookup<>(null);
+
+    /**
+     * Lookup based on system properties.
+     */
+    private static final StrLookup<String> SYSTEM_PROPERTIES_LOOKUP = new SystemPropertiesStrLookup();
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a lookup which always returns null.
+     *
+     * @return a lookup that always returns null, not null
+     */
+    public static StrLookup<?> noneLookup() {
+        return NONE_LOOKUP;
+    }
+
+    /**
+     * Returns a new lookup which uses a copy of the current
+     * {@link System#getProperties() System properties}.
+     * <p>
+     * If a security manager blocked access to system properties, then null will
+     * be returned from every lookup.
+     * <p>
+     * If a null key is used, this lookup will throw a NullPointerException.
+     *
+     * @return a lookup using system properties, not null
+     */
+    public static StrLookup<String> systemPropertiesLookup() {
+        return SYSTEM_PROPERTIES_LOOKUP;
+    }
+
+    /**
+     * Returns a lookup which looks up values using a map.
+     * <p>
+     * If the map is null, then null will be returned from every lookup.
+     * The map result object is converted to a string using toString().
+     *
+     * @param <V> the type of the values supported by the lookup
+     * @param map  the map of keys to values, may be null
+     * @return a lookup using the map, not null
+     */
+    public static <V> StrLookup<V> mapLookup(final Map<String, V> map) {
+        return new MapStrLookup<>(map);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Constructor.
+     */
+    protected StrLookup() {
+        super();
+    }
+
+    /**
+     * Looks up a String key to a String value.
+     * <p>
+     * The internal implementation may use any mechanism to return the value.
+     * The simplest implementation is to use a Map. However, virtually any
+     * implementation is possible.
+     * <p>
+     * For example, it would be possible to implement a lookup that used the
+     * key as a primary key, and looked up the value on demand from the database
+     * Or, a numeric based implementation could be created that treats the key
+     * as an integer, increments the value and return the result as a string -
+     * converting 1 to 2, 15 to 16 etc.
+     * <p>
+     * The {@link #lookup(String)} method always returns a String, regardless of
+     * the underlying data, by converting it as necessary. For example:
+     * <pre>
+     * Map&lt;String, Object&gt; map = new HashMap&lt;String, Object&gt;();
+     * map.put("number", Integer.valueOf(2));
+     * assertEquals("2", StrLookup.mapLookup(map).lookup("number"));
+     * </pre>
+     * @param key  the key to be looked up, may be null
+     * @return the matching value, null if no match
+     */
+    public abstract String lookup(String key);
+
+    //-----------------------------------------------------------------------
+    /**
+     * Lookup implementation that uses a Map.
+     */
+    static class MapStrLookup<V> extends StrLookup<V> {
+
+        /** Map keys are variable names and value. */
+        private final Map<String, V> map;
+
+        /**
+         * Creates a new instance backed by a Map.
+         *
+         * @param map  the map of keys to values, may be null
+         */
+        MapStrLookup(final Map<String, V> map) {
+            this.map = map;
+        }
+
+        /**
+         * Looks up a String key to a String value using the map.
+         * <p>
+         * If the map is null, then null is returned.
+         * The map result object is converted to a string using toString().
+         *
+         * @param key  the key to be looked up, may be null
+         * @return the matching value, null if no match
+         */
+        @Override
+        public String lookup(final String key) {
+            if (map == null) {
+                return null;
+            }
+            final Object obj = map.get(key);
+            if (obj == null) {
+                return null;
+            }
+            return obj.toString();
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Lookup implementation based on system properties.
+     */
+    private static class SystemPropertiesStrLookup extends StrLookup<String> {
+        /**
+         * {@inheritDoc} This implementation directly accesses system properties.
+         */
+        @Override
+        public String lookup(final String key) {
+            if (key.length() > 0) {
+                try {
+                    return System.getProperty(key);
+                } catch (final SecurityException scex) {
+                    // Squelched. All lookup(String) will return null.
+                }
+            }
+            return null;
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/commons-text/blob/c7cf533d/src/main/java/org/apache/commons/text/StrMatcher.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/text/StrMatcher.java b/src/main/java/org/apache/commons/text/StrMatcher.java
new file mode 100644
index 0000000..97d6673
--- /dev/null
+++ b/src/main/java/org/apache/commons/text/StrMatcher.java
@@ -0,0 +1,438 @@
+/*
+ * 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.text;
+
+import java.util.Arrays;
+
+/**
+ * A matcher class that can be queried to determine if a character array
+ * portion matches.
+ * <p>
+ * This class comes complete with various factory methods.
+ * If these do not suffice, you can subclass and implement your own matcher.
+ *
+ * @since 1.0
+ */
+public abstract class StrMatcher {
+
+    /**
+     * Matches the comma character.
+     */
+    private static final StrMatcher COMMA_MATCHER = new CharMatcher(',');
+    /**
+     * Matches the tab character.
+     */
+    private static final StrMatcher TAB_MATCHER = new CharMatcher('\t');
+    /**
+     * Matches the space character.
+     */
+    private static final StrMatcher SPACE_MATCHER = new CharMatcher(' ');
+    /**
+     * Matches the same characters as StringTokenizer,
+     * namely space, tab, newline, formfeed.
+     */
+    private static final StrMatcher SPLIT_MATCHER = new CharSetMatcher(" \t\n\r\f".toCharArray());
+    /**
+     * Matches the String trim() whitespace characters.
+     */
+    private static final StrMatcher TRIM_MATCHER = new TrimMatcher();
+    /**
+     * Matches the double quote character.
+     */
+    private static final StrMatcher SINGLE_QUOTE_MATCHER = new CharMatcher('\'');
+    /**
+     * Matches the double quote character.
+     */
+    private static final StrMatcher DOUBLE_QUOTE_MATCHER = new CharMatcher('"');
+    /**
+     * Matches the single or double quote character.
+     */
+    private static final StrMatcher QUOTE_MATCHER = new CharSetMatcher("'\"".toCharArray());
+    /**
+     * Matches no characters.
+     */
+    private static final StrMatcher NONE_MATCHER = new NoMatcher();
+
+    // -----------------------------------------------------------------------
+
+    /**
+     * Returns a matcher which matches the comma character.
+     *
+     * @return a matcher for a comma
+     */
+    public static StrMatcher commaMatcher() {
+        return COMMA_MATCHER;
+    }
+
+    /**
+     * Returns a matcher which matches the tab character.
+     *
+     * @return a matcher for a tab
+     */
+    public static StrMatcher tabMatcher() {
+        return TAB_MATCHER;
+    }
+
+    /**
+     * Returns a matcher which matches the space character.
+     *
+     * @return a matcher for a space
+     */
+    public static StrMatcher spaceMatcher() {
+        return SPACE_MATCHER;
+    }
+
+    /**
+     * Matches the same characters as StringTokenizer,
+     * namely space, tab, newline and formfeed.
+     *
+     * @return the split matcher
+     */
+    public static StrMatcher splitMatcher() {
+        return SPLIT_MATCHER;
+    }
+
+    /**
+     * Matches the String trim() whitespace characters.
+     *
+     * @return the trim matcher
+     */
+    public static StrMatcher trimMatcher() {
+        return TRIM_MATCHER;
+    }
+
+    /**
+     * Returns a matcher which matches the single quote character.
+     *
+     * @return a matcher for a single quote
+     */
+    public static StrMatcher singleQuoteMatcher() {
+        return SINGLE_QUOTE_MATCHER;
+    }
+
+    /**
+     * Returns a matcher which matches the double quote character.
+     *
+     * @return a matcher for a double quote
+     */
+    public static StrMatcher doubleQuoteMatcher() {
+        return DOUBLE_QUOTE_MATCHER;
+    }
+
+    /**
+     * Returns a matcher which matches the single or double quote character.
+     *
+     * @return a matcher for a single or double quote
+     */
+    public static StrMatcher quoteMatcher() {
+        return QUOTE_MATCHER;
+    }
+
+    /**
+     * Matches no characters.
+     *
+     * @return a matcher that matches nothing
+     */
+    public static StrMatcher noneMatcher() {
+        return NONE_MATCHER;
+    }
+
+    /**
+     * Constructor that creates a matcher from a character.
+     *
+     * @param ch  the character to match, must not be null
+     * @return a new Matcher for the given char
+     */
+    public static StrMatcher charMatcher(final char ch) {
+        return new CharMatcher(ch);
+    }
+
+    /**
+     * Constructor that creates a matcher from a set of characters.
+     *
+     * @param chars  the characters to match, null or empty matches nothing
+     * @return a new matcher for the given char[]
+     */
+    public static StrMatcher charSetMatcher(final char... chars) {
+        if (chars == null || chars.length == 0) {
+            return NONE_MATCHER;
+        }
+        if (chars.length == 1) {
+            return new CharMatcher(chars[0]);
+        }
+        return new CharSetMatcher(chars);
+    }
+
+    /**
+     * Constructor that creates a matcher from a string representing a set of characters.
+     *
+     * @param chars  the characters to match, null or empty matches nothing
+     * @return a new Matcher for the given characters
+     */
+    public static StrMatcher charSetMatcher(final String chars) {
+        if (chars == null || chars.length() == 0) {
+            return NONE_MATCHER;
+        }
+        if (chars.length() == 1) {
+            return new CharMatcher(chars.charAt(0));
+        }
+        return new CharSetMatcher(chars.toCharArray());
+    }
+
+    /**
+     * Constructor that creates a matcher from a string.
+     *
+     * @param str  the string to match, null or empty matches nothing
+     * @return a new Matcher for the given String
+     */
+    public static StrMatcher stringMatcher(final String str) {
+        if (str == null || str.length() == 0) {
+            return NONE_MATCHER;
+        }
+        return new StringMatcher(str);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Constructor.
+     */
+    protected StrMatcher() {
+        super();
+    }
+
+    /**
+     * Returns the number of matching characters, zero for no match.
+     * <p>
+     * This method is called to check for a match.
+     * The parameter <code>pos</code> represents the current position to be
+     * checked in the string <code>buffer</code> (a character array which must
+     * not be changed).
+     * The API guarantees that <code>pos</code> is a valid index for <code>buffer</code>.
+     * <p>
+     * The character array may be larger than the active area to be matched.
+     * Only values in the buffer between the specified indices may be accessed.
+     * <p>
+     * The matching code may check one character or many.
+     * It may check characters preceding <code>pos</code> as well as those
+     * after, so long as no checks exceed the bounds specified.
+     * <p>
+     * It must return zero for no match, or a positive number if a match was found.
+     * The number indicates the number of characters that matched.
+     *
+     * @param buffer  the text content to match against, do not change
+     * @param pos  the starting position for the match, valid for buffer
+     * @param bufferStart  the first active index in the buffer, valid for buffer
+     * @param bufferEnd  the end index (exclusive) of the active buffer, valid for buffer
+     * @return the number of matching characters, zero for no match
+     */
+    public abstract int isMatch(char[] buffer, int pos, int bufferStart, int bufferEnd);
+
+    /**
+     * Returns the number of matching characters, zero for no match.
+     * <p>
+     * This method is called to check for a match.
+     * The parameter <code>pos</code> represents the current position to be
+     * checked in the string <code>buffer</code> (a character array which must
+     * not be changed).
+     * The API guarantees that <code>pos</code> is a valid index for <code>buffer</code>.
+     * <p>
+     * The matching code may check one character or many.
+     * It may check characters preceding <code>pos</code> as well as those after.
+     * <p>
+     * It must return zero for no match, or a positive number if a match was found.
+     * The number indicates the number of characters that matched.
+     *
+     * @param buffer  the text content to match against, do not change
+     * @param pos  the starting position for the match, valid for buffer
+     * @return the number of matching characters, zero for no match
+     */
+    public int isMatch(final char[] buffer, final int pos) {
+        return isMatch(buffer, pos, 0, buffer.length);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Class used to define a set of characters for matching purposes.
+     */
+    static final class CharSetMatcher extends StrMatcher {
+        /** The set of characters to match. */
+        private final char[] chars;
+
+        /**
+         * Constructor that creates a matcher from a character array.
+         *
+         * @param chars  the characters to match, must not be null
+         */
+        CharSetMatcher(final char chars[]) {
+            super();
+            this.chars = chars.clone();
+            Arrays.sort(this.chars);
+        }
+
+        /**
+         * Returns whether or not the given character matches.
+         *
+         * @param buffer  the text content to match against, do not change
+         * @param pos  the starting position for the match, valid for buffer
+         * @param bufferStart  the first active index in the buffer, valid for buffer
+         * @param bufferEnd  the end index of the active buffer, valid for buffer
+         * @return the number of matching characters, zero for no match
+         */
+        @Override
+        public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
+            return Arrays.binarySearch(chars, buffer[pos]) >= 0 ? 1 : 0;
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Class used to define a character for matching purposes.
+     */
+    static final class CharMatcher extends StrMatcher {
+        /** The character to match. */
+        private final char ch;
+
+        /**
+         * Constructor that creates a matcher that matches a single character.
+         *
+         * @param ch  the character to match
+         */
+        CharMatcher(final char ch) {
+            super();
+            this.ch = ch;
+        }
+
+        /**
+         * Returns whether or not the given character matches.
+         *
+         * @param buffer  the text content to match against, do not change
+         * @param pos  the starting position for the match, valid for buffer
+         * @param bufferStart  the first active index in the buffer, valid for buffer
+         * @param bufferEnd  the end index of the active buffer, valid for buffer
+         * @return the number of matching characters, zero for no match
+         */
+        @Override
+        public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
+            return ch == buffer[pos] ? 1 : 0;
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Class used to define a set of characters for matching purposes.
+     */
+    static final class StringMatcher extends StrMatcher {
+        /** The string to match, as a character array. */
+        private final char[] chars;
+
+        /**
+         * Constructor that creates a matcher from a String.
+         *
+         * @param str  the string to match, must not be null
+         */
+        StringMatcher(final String str) {
+            super();
+            chars = str.toCharArray();
+        }
+
+        /**
+         * Returns whether or not the given text matches the stored string.
+         *
+         * @param buffer  the text content to match against, do not change
+         * @param pos  the starting position for the match, valid for buffer
+         * @param bufferStart  the first active index in the buffer, valid for buffer
+         * @param bufferEnd  the end index of the active buffer, valid for buffer
+         * @return the number of matching characters, zero for no match
+         */
+        @Override
+        public int isMatch(final char[] buffer, int pos, final int bufferStart, final int bufferEnd) {
+            final int len = chars.length;
+            if (pos + len > bufferEnd) {
+                return 0;
+            }
+            for (int i = 0; i < chars.length; i++, pos++) {
+                if (chars[i] != buffer[pos]) {
+                    return 0;
+                }
+            }
+            return len;
+        }
+        
+        @Override
+        public String toString() {
+            return super.toString() + ' ' + Arrays.toString(chars);
+        }
+
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Class used to match no characters.
+     */
+    static final class NoMatcher extends StrMatcher {
+
+        /**
+         * Constructs a new instance of <code>NoMatcher</code>.
+         */
+        NoMatcher() {
+            super();
+        }
+
+        /**
+         * Always returns <code>false</code>.
+         *
+         * @param buffer  the text content to match against, do not change
+         * @param pos  the starting position for the match, valid for buffer
+         * @param bufferStart  the first active index in the buffer, valid for buffer
+         * @param bufferEnd  the end index of the active buffer, valid for buffer
+         * @return the number of matching characters, zero for no match
+         */
+        @Override
+        public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
+            return 0;
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Class used to match whitespace as per trim().
+     */
+    static final class TrimMatcher extends StrMatcher {
+
+        /**
+         * Constructs a new instance of <code>TrimMatcher</code>.
+         */
+        TrimMatcher() {
+            super();
+        }
+
+        /**
+         * Returns whether or not the given character matches.
+         *
+         * @param buffer  the text content to match against, do not change
+         * @param pos  the starting position for the match, valid for buffer
+         * @param bufferStart  the first active index in the buffer, valid for buffer
+         * @param bufferEnd  the end index of the active buffer, valid for buffer
+         * @return the number of matching characters, zero for no match
+         */
+        @Override
+        public int isMatch(final char[] buffer, final int pos, final int bufferStart, final int bufferEnd) {
+            return buffer[pos] <= 32 ? 1 : 0;
+        }
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/commons-text/blob/c7cf533d/src/main/java/org/apache/commons/text/StrSubstitutor.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/text/StrSubstitutor.java b/src/main/java/org/apache/commons/text/StrSubstitutor.java
new file mode 100644
index 0000000..00d05f7
--- /dev/null
+++ b/src/main/java/org/apache/commons/text/StrSubstitutor.java
@@ -0,0 +1,1213 @@
+/*
+ * 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.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>
+ * 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:
+ * <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}. ${undefined.number:-1234567890}.&quot;;
+ * StrSubstitutor sub = new StrSubstitutor(valuesMap);
+ * String resolvedString = sub.replace(templateString);
+ * </pre>
+ * yielding:
+ * <pre>
+ *      The quick brown fox jumped over the lazy dog. 1234567890.
+ * </pre>
+ * <p>
+ * In addition to this usage pattern there are some static convenience methods that
+ * cover the most common use cases. These methods can be used without the need of
+ * manually creating an instance. However if multiple replace operations are to be
+ * performed, creating and reusing an instance of this class will be more efficient.
+ * <p>
+ * 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>.
+ * <p>This class is <b>not</b> thread safe.</p>
+ *
+ * @since 1.0
+ */
+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("}");
+    /**
+     * Constant for the default value delimiter of a variable.
+     */
+    public static final StrMatcher DEFAULT_VALUE_DELIMITER = StrMatcher.stringMatcher(":-");
+
+    /**
+     * 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 StrMatcher valueDelimiterMatcher;
+    /**
+     * Variable resolution is delegated to an implementor of VariableResolver.
+     */
+    private StrLookup<?> variableResolver;
+    /**
+     * The flag whether substitution in variable names is enabled.
+     */
+    private boolean enableSubstitutionInVariables;
+    /**
+     * Whether escapes should be preserved.  Default is false;
+     */
+    private boolean preserveEscapes = false;
+
+    //-----------------------------------------------------------------------
+    /**
+     * 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<>();
+        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 <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
+     * @param valueDelimiter  the variable default value delimiter, may be null
+     * @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, final String valueDelimiter) {
+        this(StrLookup.mapLookup(valueMap), prefix, suffix, escape, valueDelimiter);
+    }
+
+    /**
+     * 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);
+        this.setValueDelimiterMatcher(DEFAULT_VALUE_DELIMITER);
+    }
+
+    /**
+     * 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);
+    }
+
+    /**
+     * 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);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * 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 as a template.
+     * The source 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 CharSequence source) {
+        if (source == null) {
+            return null;
+        }
+        return replace(source, 0, source.length());
+    }
+
+    /**
+     * Replaces all the occurrences of variables with their matching values
+     * from the resolver using the given source as a template.
+     * The source 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 CharSequence 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 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 StringBuilder source) {
+        if (source == null) {
+            return false;
+        }
+        return replaceIn(source, 0, source.length());
+    }
+
+    /**
+     * Replaces all the occurrences of variables within the given source builder
+     * with their matching values from the resolver.
+     * The builder 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 StringBuilder 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 pfxMatcher = getVariablePrefixMatcher();
+        final StrMatcher suffMatcher = getVariableSuffixMatcher();
+        final char escape = getEscapeChar();
+        final StrMatcher valueDelimMatcher = getValueDelimiterMatcher();
+        final boolean substitutionInVariablesEnabled = isEnableSubstitutionInVariables();
+
+        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 = pfxMatcher.isMatch(chars, pos, offset,
+                    bufEnd);
+            if (startMatchLen == 0) {
+                pos++;
+            } else {
+                // found variable start marker
+                if (pos > offset && chars[pos - 1] == escape) {
+                    // escaped
+                    if (preserveEscapes) {
+                        pos++;
+                        continue;
+                    }
+                    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 (substitutionInVariablesEnabled
+                                && (endMatchLen = pfxMatcher.isMatch(chars,
+                                        pos, offset, bufEnd)) != 0) {
+                            // found a nested variable start
+                            nestedVarCount++;
+                            pos += endMatchLen;
+                            continue;
+                        }
+
+                        endMatchLen = suffMatcher.isMatch(chars, pos, offset,
+                                bufEnd);
+                        if (endMatchLen == 0) {
+                            pos++;
+                        } else {
+                            // found variable end marker
+                            if (nestedVarCount == 0) {
+                                String varNameExpr = new String(chars, startPos
+                                        + startMatchLen, pos - startPos
+                                        - startMatchLen);
+                                if (substitutionInVariablesEnabled) {
+                                    final StrBuilder bufName = new StrBuilder(varNameExpr);
+                                    substitute(bufName, 0, bufName.length());
+                                    varNameExpr = bufName.toString();
+                                }
+                                pos += endMatchLen;
+                                final int endPos = pos;
+
+                                String varName = varNameExpr;
+                                String varDefaultValue = null;
+
+                                if (valueDelimMatcher != 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
+                                                && pfxMatcher.isMatch(varNameExprChars, i, i, varNameExprChars.length) != 0) {
+                                            break;
+                                        }
+                                        if ((valueDelimiterMatchLen = valueDelimMatcher.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));
+                                }
+
+                                // handle cyclic substitution
+                                checkCyclicSubstitution(varName, priorVariables);
+                                priorVariables.add(varName);
+
+                                // resolve the variable
+                                String varValue = resolveVariable(varName, buf,
+                                        startPos, endPos);
+                                if (varValue == null) {
+                                    varValue = varDefaultValue;
+                                }
+                                if (varValue != null) {
+                                    // recursive replace
+                                    final int varLen = varValue.length();
+                                    buf.replace(startPos, endPos, varValue);
+                                    altered = true;
+                                    int change = substitute(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;
+                            }
+                            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));
+    }
+
+    // Variable Default Value Delimiter
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the variable default value delimiter matcher currently in use.
+     * <p>
+     * The variable default value delimiter is the characer or characters that delimite the
+     * variable name and the variable default value. This delimiter is expressed in terms of a matcher
+     * allowing advanced variable default value delimiter matches.
+     * <p>
+     * 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.
+     * <p>
+     * The variable default value delimiter is the characer or characters that delimite the
+     * variable name and the variable default value. This delimiter is expressed in terms of a matcher
+     * allowing advanced variable default value delimiter matches.
+     * <p>
+     * If the <code>valueDelimiterMatcher</code> 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.
+     * <p>
+     * The variable default value delimiter is the characer or characters that delimite 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.
+     * <p>
+     * The variable default value delimiter is the characer or characters that delimite the
+     * variable name and the variable default value. This method allows a string
+     * variable default value delimiter to be easily set.
+     * <p>
+     * If the <code>valueDelimiter</code> 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 (valueDelimiter == null || valueDelimiter.length() == 0) {
+            setValueDelimiterMatcher(null);
+            return this;
+        }
+        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) {
+        this.variableResolver = variableResolver;
+    }
+
+    // Substitution support in variable names
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a flag whether substitution is done in variable names.
+     *
+     * @return the substitution in variable names flag
+     */
+    public boolean isEnableSubstitutionInVariables() {
+        return enableSubstitutionInVariables;
+    }
+
+    /**
+     * Sets a flag whether substitution is done in variable names. If set to
+     * <b>true</b>, the names of variables can contain other variables which are
+     * processed first before the original variable is evaluated, e.g.
+     * <code>${jre-${java.version}}</code>. The default value is <b>false</b>.
+     *
+     * @param enableSubstitutionInVariables the new value of the flag
+     */
+    public void setEnableSubstitutionInVariables(
+            final boolean enableSubstitutionInVariables) {
+        this.enableSubstitutionInVariables = enableSubstitutionInVariables;
+    }
+
+    /**
+     * Returns the flag controlling whether escapes are preserved during
+     * substitution.
+     * 
+     * @return the preserve escape flag
+     */
+    public boolean isPreserveEscapes() {
+        return preserveEscapes;
+    }
+
+    /**
+     * Sets a flag controlling whether escapes are preserved during
+     * substitution.  If set to <b>true</b>, the escape character is retained
+     * during substitution (e.g. <code>$${this-is-escaped}</code> remains
+     * <code>$${this-is-escaped}</code>).  If set to <b>false</b>, the escape
+     * character is removed during substitution (e.g.
+     * <code>$${this-is-escaped}</code> becomes
+     * <code>${this-is-escaped}</code>).  The default value is <b>false</b>
+     * 
+     * @param preserveEscapes true if escapes are to be preserved
+     */
+    public void setPreserveEscapes(final boolean preserveEscapes) {
+        this.preserveEscapes = preserveEscapes;
+    }
+}


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