/*
* Copyright 2002-2004 The Apache Software Foundation.
*
* Licensed 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.lang;
import java.io.Serializable;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* <p>A set of characters.</p>
*
* <p>Instances are immutable, but instances of subclasses may not be.</p>
*
* @author Henri Yandell
* @author Stephen Colebourne
* @author Phil Steitz
* @author Pete Gieser
* @author Gary Gregory
* @since 1.0
* @version $Id: CharSet.java,v 1.22 2004/02/18 22:59:49 ggregory Exp $
*/
public class CharSet implements Serializable {
/** Serialization lock, Lang version 2.0. */
private static final long serialVersionUID = 5947847346149275958L;
/**
* A CharSet defining no characters.
* @since 2.0
*/
public static final CharSet EMPTY = new CharSet((String) null);
/**
* A CharSet defining ASCII alphabetic characters "a-zA-Z".
* @since 2.0
*/
public static final CharSet ASCII_ALPHA = new CharSet("a-zA-Z");
/**
* A CharSet defining ASCII alphabetic characters "a-z".
* @since 2.0
*/
public static final CharSet ASCII_ALPHA_LOWER = new CharSet("a-z");
/**
* A CharSet defining ASCII alphabetic characters "A-Z".
* @since 2.0
*/
public static final CharSet ASCII_ALPHA_UPPER = new CharSet("A-Z");
/**
* A CharSet defining ASCII alphabetic characters "0-9".
* @since 2.0
*/
public static final CharSet ASCII_NUMERIC = new CharSet("0-9");
/**
* A Map of the common cases used in the factory.
* Subclasses can add more common patterns if desired.
* @since 2.0
*/
protected static final Map COMMON = new HashMap();
static {
COMMON.put(null, EMPTY);
COMMON.put("", EMPTY);
COMMON.put("a-zA-Z", ASCII_ALPHA);
COMMON.put("A-Za-z", ASCII_ALPHA);
COMMON.put("a-z", ASCII_ALPHA_LOWER);
COMMON.put("A-Z", ASCII_ALPHA_UPPER);
COMMON.put("0-9", ASCII_NUMERIC);
}
/** The set of CharRange objects. */
private Set set = new HashSet();
//-----------------------------------------------------------------------
/**
* <p>Factory method to create a new CharSet using a special syntax.</p>
*
* <ul>
* <li><code>null</code> or empty string ("")
* - set containing no characters</li>
* <li>Single character, such as "a"
* - set containing just that character</li>
* <li>Multi character, such as "a-e"
* - set containing characters from one character to the other</li>
* <li>Negated, such as "^a" or "^a-e"
* - set containing all characters except those defined</li>
* <li>Combinations, such as "abe-g"
* - set containing all the characters from the individual sets</li>
* </ul>
*
* <p>The matching order is:</p>
* <ol>
* <li>Negated multi character range, such as "^a-e"
* <li>Ordinary multi character range, such as "a-e"
* <li>Negated single character, such as "^a"
* <li>Ordinary single character, such as "a"
* </ol>
* <p>Matching works left to right. Once a match is found the
* search starts again from the next character.</p>
*
* <p>If the same range is defined twice using the same syntax, only
* one range will be kept.
* Thus, "a-ca-c" creates only one range of "a-c".</p>
*
* <p>If the start and end of a range are in the wrong order,
* they are reversed. Thus "a-e" is the same as "e-a".
* As a result, "a-ee-a" would create only one range,
* as the "a-e" and "e-a" are the same.</p>
*
* <p>The set of characters represented is the union of the specified ranges.</p>
*
* <p>All CharSet objects returned by this method will be immutable.</p>
*
* @param setStr the String describing the set, may be null
* @return a CharSet instance
* @since 2.0
*/
public static CharSet getInstance(String setStr) {
Object set = COMMON.get(setStr);
if (set != null) {
return (CharSet) set;
}
return new CharSet(setStr);
}
//-----------------------------------------------------------------------
/**
* <p>Constructs a new CharSet using the set syntax.</p>
*
* @param setStr the String describing the set, may be null
* @since 2.0
*/
protected CharSet(String setStr) {
super();
add(setStr);
}
/**
* <p>Constructs a new CharSet using the set syntax.
* Each string is merged in with the set.</p>
*
* @param set Strings to merge into the initial set
* @throws NullPointerException if set is <code>null</code>
*/
protected CharSet(String[] set) {
super();
int sz = set.length;
for (int i = 0; i < sz; i++) {
add(set[i]);
}
}
//-----------------------------------------------------------------------
/**
* <p>Add a set definition string to the <code>CharSet</code>.</p>
*
* @param str set definition string
*/
protected void add(String str) {
if (str == null) {
return;
}
int len = str.length();
int pos = 0;
while (pos < len) {
int remainder = (len - pos);
if (remainder >= 4 && str.charAt(pos) == '^' && str.charAt(pos + 2) == '-') {
// negated range
set.add(new CharRange(str.charAt(pos + 1), str.charAt(pos + 3), true));
pos += 4;
} else if (remainder >= 3 && str.charAt(pos + 1) == '-') {
// range
set.add(new CharRange(str.charAt(pos), str.charAt(pos + 2)));
pos += 3;
} else if (remainder >= 2 && str.charAt(pos) == '^') {
// negated char
set.add(new CharRange(str.charAt(pos + 1), true));
pos += 2;
} else {
// char
set.add(new CharRange(str.charAt(pos)));
pos += 1;
}
}
}
//-----------------------------------------------------------------------
/**
* <p>Gets the internal set as an array of CharRange objects.</p>
*
* @return an array of immutable CharRange objects
* @since 2.0
*/
public CharRange[] getCharRanges() {
return (CharRange[]) set.toArray(new CharRange[set.size()]);
}
//-----------------------------------------------------------------------
/**
* <p>Does the <code>CharSet</code> contain the specified
* character <code>ch</code>.</p>
*
* @param ch the character to check for
* @return <code>true</code> if the set contains the characters
*/
public boolean contains(char ch) {
for (Iterator it = set.iterator(); it.hasNext();) {
CharRange range = (CharRange) it.next();
if (range.contains(ch)) {
return true;
}
}
return false;
}
// Basics
//-----------------------------------------------------------------------
/**
* <p>Compares two CharSet objects, returning true if they represent
* exactly the same set of characters defined in the same way.</p>
*
* <p>The two sets <code>abc</code> and <code>a-c</code> are <i>not</i>
* equal according to this method.</p>
*
* @param obj the object to compare to
* @return true if equal
* @since 2.0
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof CharSet == false) {
return false;
}
CharSet other = (CharSet) obj;
return (set.equals(other.set));
}
/**
* <p>Gets a hashCode compatible with the equals method.</p>
*
* @return a suitable hashCode
* @since 2.0
*/
public int hashCode() {
return 89 + set.hashCode();
}
/**
* <p>Gets a string representation of the set.</p>
*
* @return string representation of the set
*/
public String toString() {
return set.toString();
}
}
