com.topologi.diffx.event.impl.SpaceEvent Maven / Gradle / Ivy
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/*
* This file is part of the DiffX library.
*
* For licensing information please see the file license.txt included in the release.
* A copy of this licence can also be found at
* http://www.opensource.org/licenses/artistic-license-2.0.php
*/
package com.topologi.diffx.event.impl;
import com.topologi.diffx.event.TextEvent;
/**
* A particular type of event reserved for white spaces.
*
* @author Christophe Lauret
* @version 27 March 2010
*/
public final class SpaceEvent extends CharactersEventBase implements TextEvent {
/**
* A static instance for the single white spaces.
*
* Use this constant instead of creating new instances
*/
public static final SpaceEvent SINGLE_WHITESPACE = new SpaceEvent(" ");
/**
* A static instance for the double white spaces.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceEvent DOUBLE_WHITESPACE = new SpaceEvent(" ");
/**
* A static instance for the new lines.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceEvent NEW_LINE = new SpaceEvent("\n");
/**
* A static instance for tabs.
*
*
Use this constant instead of creating new instances
*/
public static final SpaceEvent TAB = new SpaceEvent("\t");
/**
* Creates a new word event.
*
* @param w The word as a string.
*
* @throws NullPointerException If the given String is null.
*/
public SpaceEvent(CharSequence w) throws NullPointerException {
super(w);
}
@Override
public String toString() {
return "space: \""+toString(getCharacters().toCharArray())+'"';
}
/**
* Returns the white space event corresponding to the given string.
*
* @param space The string for the white space event.
*
* @return A readable string.
*/
public static SpaceEvent getInstance(CharSequence space) {
// check constants
if (" ".equals(space)) return SINGLE_WHITESPACE;
if (" ".equals(space)) return DOUBLE_WHITESPACE;
if ("\n".equals(space)) return NEW_LINE;
if ("\t".equals(space)) return TAB;
// create a new instance
return new SpaceEvent(space);
}
/**
* Returns the white space event corresponding to the given string.
*
* @param c The string for the white space event.
*
* @return A readable string.
*/
public static SpaceEvent 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
// FIXME wasteful!!
return new SpaceEvent(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) {
StringBuffer out = new StringBuffer();
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();
}
}