A contiguous range of characters, optionally negated.
* *Instances are immutable.
* * @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; //----------------------------------------------------------------------- /** *Constructs a CharRange
over a single character.
Constructs a CharRange
over a single character,
* optionally negating the range.
A negated range includes everything except the specified char.
* * @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); } /** *Constructs a CharRange
over a set of characters.
Constructs a CharRange
over a set of characters,
* optionally negating the range.
A negated range includes everything except that defined by the * start and end characters.
* *If start and end are in the wrong order, they are reversed.
* Thus a-e
is the same as e-a
.
Gets the start character for this character range.
* * @return the start char (inclusive) */ public char getStart() { return this.start; } /** *Gets the end character for this character range.
* * @return the end char (inclusive) */ public char getEnd() { return this.end; } /** *Is this CharRange
negated.
A negated range includes everything except that defined by the * start and end characters.
* * @returntrue
is negated
*/
public boolean isNegated() {
return negated;
}
// Contains
//-----------------------------------------------------------------------
/**
* Is the character specified contained in this range.
* * @param ch the character to check * @returntrue
if this range contains the input character
*/
public boolean contains(char ch) {
return (ch >= start && ch <= end) != negated;
}
/**
* Are all the characters of the passed in range contained in * this range.
* * @param range the range to check against * @returntrue
if this range entirely contains the input range
* @throws IllegalArgumentException if null
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
//-----------------------------------------------------------------------
/**
* Compares two CharRange objects, returning true if they represent * exactly the same range of characters defined in the same way.
* * @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; } /** *Gets a hashCode compatible with the equals method.
* * @return a suitable hashCode */ public int hashCode() { return 83 + start + 7 * end + (negated ? 1 : 0); } /** *Gets a string representation of the character range.
* * @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; } }