| /* |
| * 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; |
| |
| /** |
| * The {@code StringTokenizer} class allows an application to break a string |
| * into tokens by performing code point comparison. The {@code StringTokenizer} |
| * methods do not distinguish among identifiers, numbers, and quoted strings, |
| * nor do they recognize and skip comments. |
| * <p> |
| * The set of delimiters (the codepoints that separate tokens) may be specified |
| * either at creation time or on a per-token basis. |
| * <p> |
| * An instance of {@code StringTokenizer} behaves in one of three ways, |
| * depending on whether it was created with the {@code returnDelimiters} flag |
| * having the value {@code true} or {@code false}: |
| * <ul> |
| * <li>If returnDelims is {@code false}, delimiter code points serve to separate |
| * tokens. A token is a maximal sequence of consecutive code points that are not |
| * delimiters. |
| * <li>If returnDelims is {@code true}, delimiter code points are themselves |
| * considered to be tokens. In this case a token will be received for each |
| * delimiter code point. |
| * </ul> |
| * <p> |
| * A token is thus either one delimiter code point, or a maximal sequence of |
| * consecutive code points that are not delimiters. |
| * <p> |
| * A {@code StringTokenizer} object internally maintains a current position |
| * within the string to be tokenized. Some operations advance this current |
| * position past the code point processed. |
| * <p> |
| * A token is returned by taking a substring of the string that was used to |
| * create the {@code StringTokenizer} object. |
| * <p> |
| * Here's an example of the use of the default delimiter {@code StringTokenizer} |
| * : <blockquote> |
| * |
| * <pre> |
| * StringTokenizer st = new StringTokenizer("this is a test"); |
| * while (st.hasMoreTokens()) { |
| * println(st.nextToken()); |
| * } |
| * </pre> |
| * |
| * </blockquote> |
| * <p> |
| * This prints the following output: <blockquote> |
| * |
| * <pre> |
| * this |
| * is |
| * a |
| * test |
| * </pre> |
| * |
| * </blockquote> |
| * <p> |
| * Here's an example of how to use a {@code StringTokenizer} with a user |
| * specified delimiter: <blockquote> |
| * |
| * <pre> |
| * StringTokenizer st = new StringTokenizer( |
| * "this is a test with supplementary characters \ud800\ud800\udc00\udc00", |
| * " \ud800\udc00"); |
| * while (st.hasMoreTokens()) { |
| * println(st.nextToken()); |
| * } |
| * </pre> |
| * |
| * </blockquote> |
| * <p> |
| * This prints the following output: <blockquote> |
| * |
| * <pre> |
| * this |
| * is |
| * a |
| * test |
| * with |
| * supplementary |
| * characters |
| * \ud800 |
| * \udc00 |
| * </pre> |
| * |
| * </blockquote> |
| */ |
| public class StringTokenizer implements Enumeration<Object> { |
| |
| private String string; |
| |
| private String delimiters; |
| |
| private boolean returnDelimiters; |
| |
| private int position; |
| |
| /** |
| * Constructs a new {@code StringTokenizer} for the parameter string using |
| * whitespace as the delimiter. The {@code returnDelimiters} flag is set to |
| * {@code false}. |
| * |
| * @param string |
| * the string to be tokenized. |
| */ |
| public StringTokenizer(String string) { |
| this(string, " \t\n\r\f", false); |
| } |
| |
| /** |
| * Constructs a new {@code StringTokenizer} for the parameter string using |
| * the specified delimiters. The {@code returnDelimiters} flag is set to |
| * {@code false}. If {@code delimiters} is {@code null}, this constructor |
| * doesn't throw an {@code Exception}, but later calls to some methods might |
| * throw a {@code NullPointerException}. |
| * |
| * @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 {@code StringTokenizer} for the parameter string using |
| * the specified delimiters, returning the delimiters as tokens if the |
| * parameter {@code returnDelimiters} is {@code true}. If {@code delimiters} |
| * is null this constructor doesn't throw an {@code Exception}, but later |
| * calls to some methods might throw a {@code NullPointerException}. |
| * |
| * @param string |
| * the string to be tokenized. |
| * @param delimiters |
| * the delimiters to use. |
| * @param returnDelimiters |
| * {@code 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 {@code |
| * Exception} will result from a call to {@code nextToken()}. |
| */ |
| 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 {@code true} if unprocessed tokens remain. This method is |
| * implemented in order to satisfy the {@code Enumeration} interface. |
| * |
| * @return {@code true} if unprocessed tokens remain. |
| */ |
| public boolean hasMoreElements() { |
| return hasMoreTokens(); |
| } |
| |
| /** |
| * Returns {@code true} if unprocessed tokens remain. |
| * |
| * @return {@code true} if unprocessed tokens remain. |
| */ |
| public boolean hasMoreTokens() { |
| if (delimiters == null) { |
| throw new NullPointerException(); |
| } |
| 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 {@code Object}. This method is |
| * implemented in order to satisfy the {@code Enumeration} interface. |
| * |
| * @return next token in the string as an {@code Object} |
| * @throws NoSuchElementException |
| * if no tokens remain. |
| */ |
| public Object nextElement() { |
| return nextToken(); |
| } |
| |
| /** |
| * Returns the next token in the string as a {@code String}. |
| * |
| * @return next token in the string as a {@code String}. |
| * @throws NoSuchElementException |
| * if no tokens remain. |
| */ |
| public String nextToken() { |
| if (delimiters == null) { |
| throw new NullPointerException(); |
| } |
| 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 {@code 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 {@code String}. |
| * @throws NoSuchElementException |
| * if no tokens remain. |
| */ |
| public String nextToken(String delims) { |
| this.delimiters = delims; |
| return nextToken(); |
| } |
| } |
