/*
* 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 java.util;
/**
* String tokenizer is used to break a string apart into tokens.
*
* If returnDelimiters is false, successive calls to nextToken() return maximal
* blocks of characters that do not contain a delimiter.
*
* If returnDelimiters is true, delimiters are considered to be tokens, and
* successive calls to nextToken() return either a one character delimiter, or a
* maximal block of text between delimiters.
*/
public class StringTokenizer implements Enumeration<Object> {
private String string;
private String delimiters;
private boolean returnDelimiters;
private int position;
/**
* Constructs a new StringTokenizer for string using whitespace as the
* delimiter, returnDelimiters is false.
*
* @param string
* the string to be tokenized
*/
public StringTokenizer(String string) {
this(string, " \t\n\r\f", false); //$NON-NLS-1$
}
/**
* Constructs a new StringTokenizer for string using the specified
* delimiters, returnDelimiters is false.
*
* @param string
* the string to be tokenized
* @param delimiters
* the delimiters to use
*/
public StringTokenizer(String string, String delimiters) {
this(string, delimiters, false);
}
/**
* Constructs a new StringTokenizer for string using the specified
* delimiters and returning delimiters as tokens when specified.
*
* @param string
* the string to be tokenized
* @param delimiters
* the delimiters to use
* @param returnDelimiters
* true to return each delimiter as a token
*/
public StringTokenizer(String string, String delimiters,
boolean returnDelimiters) {
if (string != null) {
this.string = string;
this.delimiters = delimiters;
this.returnDelimiters = returnDelimiters;
this.position = 0;
} else
throw new NullPointerException();
}
/**
* Returns the number of unprocessed tokens remaining in the string.
*
* @return number of tokens that can be retreived before an exception will
* result
*/
public int countTokens() {
int count = 0;
boolean inToken = false;
for (int i = position, length = string.length(); i < length; i++) {
if (delimiters.indexOf(string.charAt(i), 0) >= 0) {
if (returnDelimiters)
count++;
if (inToken) {
count++;
inToken = false;
}
} else {
inToken = true;
}
}
if (inToken)
count++;
return count;
}
/**
* Returns true if unprocessed tokens remain.
*
* @return true if unprocessed tokens remain
*/
public boolean hasMoreElements() {
return hasMoreTokens();
}
/**
* Returns true if unprocessed tokens remain.
*
* @return true if unprocessed tokens remain
*/
public boolean hasMoreTokens() {
int length = string.length();
if (position < length) {
if (returnDelimiters)
return true; // there is at least one character and even if
// it is a delimiter it is a token
// otherwise find a character which is not a delimiter
for (int i = position; i < length; i++)
if (delimiters.indexOf(string.charAt(i), 0) == -1)
return true;
}
return false;
}
/**
* Returns the next token in the string as an Object.
*
* @return next token in the string as an Object
* @exception NoSuchElementException
* if no tokens remain
*/
public Object nextElement() {
return nextToken();
}
/**
* Returns the next token in the string as a String.
*
* @return next token in the string as a String
* @exception NoSuchElementException
* if no tokens remain
*/
public String nextToken() {
int i = position;
int length = string.length();
if (i < length) {
if (returnDelimiters) {
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return String.valueOf(string.charAt(position++));
for (position++; position < length; position++)
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return string.substring(i, position);
return string.substring(i);
}
while (i < length && delimiters.indexOf(string.charAt(i), 0) >= 0)
i++;
position = i;
if (i < length) {
for (position++; position < length; position++)
if (delimiters.indexOf(string.charAt(position), 0) >= 0)
return string.substring(i, position);
return string.substring(i);
}
}
throw new NoSuchElementException();
}
/**
* Returns the next token in the string as a String. The delimiters used are
* changed to the specified delimiters.
*
* @param delims
* the new delimiters to use
* @return next token in the string as a String
* @exception NoSuchElementException
* if no tokens remain
*/
public String nextToken(String delims) {
this.delimiters = delims;
return nextToken();
}
}
|