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With inspiration from other libraries
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3;
import java.io.Serializable;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* A contiguous range of characters, optionally negated.
*
* Instances are immutable.
*
* #ThreadSafe#
* @since 1.0
*/
// TODO: This is no longer public and will be removed later as CharSet is moved
// to depend on Range.
final class CharRange implements Iterable, 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 {@code 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 {@code a-e} is the same as {@code e-a}.
*
* @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
*/
private CharRange(char start, char end, final boolean negated) {
super();
if (start > end) {
final char temp = start;
start = end;
end = temp;
}
this.start = start;
this.end = end;
this.negated = negated;
}
/**
* Constructs a {@code CharRange} over a single character.
*
* @param ch only character in this range
* @return the new CharRange object
* @see CharRange#CharRange(char, char, boolean)
* @since 2.5
*/
public static CharRange is(final char ch) {
return new CharRange(ch, ch, false);
}
/**
* Constructs a negated {@code CharRange} over a single character.
*
* @param ch only character in this range
* @return the new CharRange object
* @see CharRange#CharRange(char, char, boolean)
* @since 2.5
*/
public static CharRange isNot(final char ch) {
return new CharRange(ch, ch, true);
}
/**
* Constructs a {@code CharRange} over a set of characters.
*
* @param start first character, inclusive, in this range
* @param end last character, inclusive, in this range
* @return the new CharRange object
* @see CharRange#CharRange(char, char, boolean)
* @since 2.5
*/
public static CharRange isIn(final char start, final char end) {
return new CharRange(start, end, false);
}
/**
* Constructs a negated {@code CharRange} over a set of characters.
*
* @param start first character, inclusive, in this range
* @param end last character, inclusive, in this range
* @return the new CharRange object
* @see CharRange#CharRange(char, char, boolean)
* @since 2.5
*/
public static CharRange isNotIn(final char start, final char end) {
return new CharRange(start, end, true);
}
// Accessors
//-----------------------------------------------------------------------
/**
* 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 {@code CharRange} negated.
*
* A negated range includes everything except that defined by the
* start and end characters.
*
* @return {@code true} if negated
*/
public boolean isNegated() {
return negated;
}
// Contains
//-----------------------------------------------------------------------
/**
* Is the character specified contained in this range.
*
* @param ch the character to check
* @return {@code true} if this range contains the input character
*/
public boolean contains(final 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
* @return {@code true} if this range entirely contains the input range
* @throws IllegalArgumentException if {@code null} input
*/
public boolean contains(final CharRange range) {
Validate.isTrue(range != null, "The Range must not be null");
if (negated) {
if (range.negated) {
return start >= range.start && end <= range.end;
}
return range.end < start || range.start > end;
}
if (range.negated) {
return start == 0 && end == Character.MAX_VALUE;
}
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
*/
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof CharRange)) {
return false;
}
final 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
*/
@Override
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
*/
@Override
public String toString() {
if (iToString == null) {
final StringBuilder buf = new StringBuilder(4);
if (isNegated()) {
buf.append('^');
}
buf.append(start);
if (start != end) {
buf.append('-');
buf.append(end);
}
iToString = buf.toString();
}
return iToString;
}
// Expansions
//-----------------------------------------------------------------------
/**
* Returns an iterator which can be used to walk through the characters described by this range.
*
* #NotThreadSafe# the iterator is not thread-safe
* @return an iterator to the chars represented by this range
* @since 2.5
*/
@Override
public Iterator iterator() {
return new CharacterIterator(this);
}
/**
* Character {@link Iterator}.
* #NotThreadSafe#
*/
private static class CharacterIterator implements Iterator {
/** The current character */
private char current;
private final CharRange range;
private boolean hasNext;
/**
* Construct a new iterator for the character range.
*
* @param r The character range
*/
private CharacterIterator(final CharRange r) {
range = r;
hasNext = true;
if (range.negated) {
if (range.start == 0) {
if (range.end == Character.MAX_VALUE) {
// This range is an empty set
hasNext = false;
} else {
current = (char) (range.end + 1);
}
} else {
current = 0;
}
} else {
current = range.start;
}
}
/**
* Prepare the next character in the range.
*/
private void prepareNext() {
if (range.negated) {
if (current == Character.MAX_VALUE) {
hasNext = false;
} else if (current + 1 == range.start) {
if (range.end == Character.MAX_VALUE) {
hasNext = false;
} else {
current = (char) (range.end + 1);
}
} else {
current = (char) (current + 1);
}
} else if (current < range.end) {
current = (char) (current + 1);
} else {
hasNext = false;
}
}
/**
* Has the iterator not reached the end character yet?
*
* @return {@code true} if the iterator has yet to reach the character date
*/
@Override
public boolean hasNext() {
return hasNext;
}
/**
* Return the next character in the iteration
*
* @return {@code Character} for the next character
*/
@Override
public Character next() {
if (!hasNext) {
throw new NoSuchElementException();
}
final char cur = current;
prepareNext();
return Character.valueOf(cur);
}
/**
* Always throws UnsupportedOperationException.
*
* @throws UnsupportedOperationException
* @see java.util.Iterator#remove()
*/
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}