A contiguous range of characters, optionally negated.
/*
* 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.
*/
import java.io.Serializable;
/**
* <p>A contiguous range of characters, optionally negated.</p>
*
* <p>Instances are immutable.</p>
*
* @author Stephen Colebourne
* @author Chris Feldhacker
* @author Gary Gregory
* @since 1.0
* @version $Id: CharRange.java 471626 2006-11-06 04:02:09Z bayard $
*/
public final class CharRange implements Serializable {
/**
* Required for serialization support. Lang version 2.0.
*
* @see java.io.Serializable
*/
private static final long serialVersionUID = 8270183163158333422L;
/** The first character, inclusive, in the range. */
private final char start;
/** The last character, inclusive, in the range. */
private final char end;
/** True if the range is everything except the characters specified. */
private final boolean negated;
/** Cached toString. */
private transient String iToString;
//-----------------------------------------------------------------------
/**
* <p>Constructs a <code>CharRange</code> over a single character.</p>
*
* @param ch only character in this range
*/
public CharRange(char ch) {
this(ch, ch, false);
}
/**
* <p>Constructs a <code>CharRange</code> over a single character,
* optionally negating the range.</p>
*
* <p>A negated range includes everything except the specified char.</p>
*
* @param ch only character in this range
* @param negated true to express everything except the range
*/
public CharRange(char ch, boolean negated) {
this(ch, ch, negated);
}
/**
* <p>Constructs a <code>CharRange</code> over a set of characters.</p>
*
* @param start first character, inclusive, in this range
* @param end last character, inclusive, in this range
*/
public CharRange(char start, char end) {
this(start, end, false);
}
/**
* <p>Constructs a <code>CharRange</code> over a set of characters,
* optionally negating the range.</p>
*
* <p>A negated range includes everything except that defined by the
* start and end characters.</p>
*
* <p>If start and end are in the wrong order, they are reversed.
* Thus <code>a-e</code> is the same as <code>e-a</code>.</p>
*
* @param start first character, inclusive, in this range
* @param end last character, inclusive, in this range
* @param negated true to express everything except the range
*/
public CharRange(char start, char end, boolean negated) {
super();
if (start > end) {
char temp = start;
start = end;
end = temp;
}
this.start = start;
this.end = end;
this.negated = negated;
}
// Accessors
//-----------------------------------------------------------------------
/**
* <p>Gets the start character for this character range.</p>
*
* @return the start char (inclusive)
*/
public char getStart() {
return this.start;
}
/**
* <p>Gets the end character for this character range.</p>
*
* @return the end char (inclusive)
*/
public char getEnd() {
return this.end;
}
/**
* <p>Is this <code>CharRange</code> negated.</p>
*
* <p>A negated range includes everything except that defined by the
* start and end characters.</p>
*
* @return <code>true</code> is negated
*/
public boolean isNegated() {
return negated;
}
// Contains
//-----------------------------------------------------------------------
/**
* <p>Is the character specified contained in this range.</p>
*
* @param ch the character to check
* @return <code>true</code> if this range contains the input character
*/
public boolean contains(char ch) {
return (ch >= start && ch <= end) != negated;
}
/**
* <p>Are all the characters of the passed in range contained in
* this range.</p>
*
* @param range the range to check against
* @return <code>true</code> if this range entirely contains the input range
* @throws IllegalArgumentException if <code>null</code> input
*/
public boolean contains(CharRange range) {
if (range == null) {
throw new IllegalArgumentException("The Range must not be null");
}
if (negated) {
if (range.negated) {
return start >= range.start && end <= range.end;
} else {
return range.end < start || range.start > end;
}
} else {
if (range.negated) {
return start == 0 && end == Character.MAX_VALUE;
} else {
return start <= range.start && end >= range.end;
}
}
}
// Basics
//-----------------------------------------------------------------------
/**
* <p>Compares two CharRange objects, returning true if they represent
* exactly the same range of characters defined in the same way.</p>
*
* @param obj the object to compare to
* @return true if equal
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof CharRange == false) {
return false;
}
CharRange other = (CharRange) obj;
return start == other.start && end == other.end && negated == other.negated;
}
/**
* <p>Gets a hashCode compatible with the equals method.</p>
*
* @return a suitable hashCode
*/
public int hashCode() {
return 83 + start + 7 * end + (negated ? 1 : 0);
}
/**
* <p>Gets a string representation of the character range.</p>
*
* @return string representation of this range
*/
public String toString() {
if (iToString == null) {
StringBuffer buf = new StringBuffer(4);
if (isNegated()) {
buf.append('^');
}
buf.append(start);
if (start != end) {
buf.append('-');
buf.append(end);
}
iToString = buf.toString();
}
return iToString;
}
}
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