org.pageseeder.diffx.token.impl.SpaceToken Maven / Gradle / Ivy
/*
* Copyright 2010-2015 Allette Systems (Australia)
* http://www.allette.com.au
*
* 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.pageseeder.diffx.token.impl;
import org.pageseeder.diffx.token.TextToken;
/**
* A particular type of token reserved for white spaces.
*
* @author Christophe Lauret
* @version 27 March 2010
*/
public final class SpaceToken extends CharactersTokenBase implements TextToken {
/**
* A static instance for the single white spaces.
*
* Use this constant instead of creating new instances
*/
public static final SpaceToken SINGLE_WHITESPACE = new SpaceToken(" ");
/**
* A static instance for the double white spaces.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceToken DOUBLE_WHITESPACE = new SpaceToken(" ");
/**
* A static instance for the new lines.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceToken NEW_LINE = new SpaceToken("\n");
/**
* A static instance for tabs.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceToken TAB = new SpaceToken("\t");
/**
* Creates a new space token.
*
* @param s The space as a string.
*
* @throws NullPointerException If the given String is null.
*/
public SpaceToken(CharSequence s) throws NullPointerException {
super(s);
}
@Override
public String toString() {
return "space: \"" + toString(getCharacters().toCharArray()) + '"';
}
/**
* Returns the white space token corresponding to the given string.
*
* @param space The string for the white space token.
*
* @return A readable string.
*/
public static SpaceToken getInstance(CharSequence space) {
// check constants
if (" ".contentEquals(space)) return SINGLE_WHITESPACE;
if (" ".contentEquals(space)) return DOUBLE_WHITESPACE;
if ("\n".contentEquals(space)) return NEW_LINE;
if ("\t".contentEquals(space)) return TAB;
// create a new instance
return new SpaceToken(space);
}
/**
* Returns the white space token corresponding to the given string.
*
* @param c The string for the white space token.
*
* @return A readable string.
*/
public static SpaceToken getInstance(char c) {
// check constants
if (c == ' ') return SINGLE_WHITESPACE;
if (c == '\n') return NEW_LINE;
if (c == '\t') return TAB;
// create a new instance
return new SpaceToken(String.valueOf(c));
}
/**
* Returns the white space characters as a readable string.
*
* @param chars The whitespace characters
*
* @return A readable string.
*/
private static String toString(char[] chars) {
StringBuilder out = new StringBuilder();
for (char c : chars) {
switch (c) {
case '\n':
out.append("\\n");
break;
case '\t':
out.append("\\t");
break;
default:
out.append(c);
}
}
return out.toString();
}
}