Initial revision

From-SVN: r102074

libjava/classpath/java/util/StringTokenizer.java

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+/* StringTokenizer -- breaks a String into tokens
+   Copyright (C) 1998, 1999, 2001, 2002, 2005  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.util;
+
+/**
+ * This class splits a string into tokens.  The caller can set on which
+ * delimiters the string should be split and if the delimiters should be
+ * returned. This is much simpler than {@link java.io.StreamTokenizer}.
+ *
+ * <p>You may change the delimiter set on the fly by calling
+ * nextToken(String).  But the semantic is quite difficult; it even
+ * depends on calling <code>hasMoreTokens()</code>.  You should call
+ * <code>hasMoreTokens()</code> before, otherwise the old delimiters
+ * after the last token are candidates for being returned.
+ *
+ * <p>If you want to get the delimiters, you have to use the three argument
+ * constructor.  The delimiters are returned as token consisting of a
+ * single character.
+ *
+ * @author Jochen Hoenicke
+ * @author Warren Levy (warrenl@cygnus.com)
+ * @see java.io.StreamTokenizer
+ * @status updated to 1.4
+ */
+public class StringTokenizer implements Enumeration
+{
+  // WARNING: StringTokenizer is a CORE class in the bootstrap cycle. See the
+  // comments in vm/reference/java/lang/Runtime for implications of this fact.
+
+  /**
+   * The position in the str, where we currently are.
+   */
+  private int pos;
+
+  /**
+   * The string that should be split into tokens.
+   */
+  private final String str;
+
+  /**
+   * The length of the string.
+   */
+  private final int len;
+
+  /**
+   * The string containing the delimiter characters.
+   */
+  private String delim;
+
+  /**
+   * Tells, if we should return the delimiters.
+   */
+  private final boolean retDelims;
+
+  /**
+   * Creates a new StringTokenizer for the string <code>str</code>,
+   * that should split on the default delimiter set (space, tab,
+   * newline, return and formfeed), and which doesn't return the
+   * delimiters.
+   *
+   * @param str The string to split
+   * @throws NullPointerException if str is null
+   */
+  public StringTokenizer(String str)
+  {
+    this(str, " \t\n\r\f", false);
+  }
+
+  /**
+   * Create a new StringTokenizer, that splits the given string on
+   * the given delimiter characters.  It doesn't return the delimiter
+   * characters.
+   *
+   * @param str the string to split
+   * @param delim a string containing all delimiter characters
+   * @throws NullPointerException if either argument is null
+   */
+  public StringTokenizer(String str, String delim)
+  {
+    this(str, delim, false);
+  }
+
+  /**
+   * Create a new StringTokenizer, that splits the given string on
+   * the given delimiter characters.  If you set
+   * <code>returnDelims</code> to <code>true</code>, the delimiter
+   * characters are returned as tokens of their own.  The delimiter
+   * tokens always consist of a single character.
+   *
+   * @param str the string to split
+   * @param delim a string containing all delimiter characters
+   * @param returnDelims tells, if you want to get the delimiters
+   * @throws NullPointerException if str or delim is null
+   */
+  public StringTokenizer(String str, String delim, boolean returnDelims)
+  {
+    len = str.length();
+    this.str = str;
+    // The toString() hack causes the NullPointerException.
+    this.delim = delim.toString();
+    this.retDelims = returnDelims;
+    this.pos = 0;
+  }
+
+  /**
+   * Tells if there are more tokens.
+   *
+   * @return true if the next call of nextToken() will succeed
+   */
+  public boolean hasMoreTokens()
+  {
+    if (! retDelims)
+      {
+        while (pos < len && delim.indexOf(str.charAt(pos)) >= 0)
+          pos++;
+      }
+    return pos < len;
+  }
+
+  /**
+   * Returns the nextToken, changing the delimiter set to the given
+   * <code>delim</code>.  The change of the delimiter set is
+   * permanent, ie. the next call of nextToken(), uses the same
+   * delimiter set.
+   *
+   * @param delim a string containing the new delimiter characters
+   * @return the next token with respect to the new delimiter characters
+   * @throws NoSuchElementException if there are no more tokens
+   * @throws NullPointerException if delim is null
+   */
+  public String nextToken(String delim) throws NoSuchElementException
+  {
+    this.delim = delim;
+    return nextToken();
+  }
+
+  /**
+   * Returns the nextToken of the string.
+   *
+   * @return the next token with respect to the current delimiter characters
+   * @throws NoSuchElementException if there are no more tokens
+   */
+  public String nextToken() throws NoSuchElementException
+  {
+    if (pos < len && delim.indexOf(str.charAt(pos)) >= 0)
+      {
+        if (retDelims)
+          return str.substring(pos, ++pos);
+        while (++pos < len && delim.indexOf(str.charAt(pos)) >= 0);
+      }
+    if (pos < len)
+      {
+        int start = pos;
+        while (++pos < len && delim.indexOf(str.charAt(pos)) < 0);
+
+        return str.substring(start, pos);
+      }
+    throw new NoSuchElementException();
+  }
+
+  /**
+   * This does the same as hasMoreTokens. This is the
+   * <code>Enumeration</code> interface method.
+   *
+   * @return true, if the next call of nextElement() will succeed
+   * @see #hasMoreTokens()
+   */
+  public boolean hasMoreElements()
+  {
+    return hasMoreTokens();
+  }
+
+  /**
+   * This does the same as nextTokens. This is the
+   * <code>Enumeration</code> interface method.
+   *
+   * @return the next token with respect to the current delimiter characters
+   * @throws NoSuchElementException if there are no more tokens
+   * @see #nextToken()
+   */
+  public Object nextElement() throws NoSuchElementException
+  {
+    return nextToken();
+  }
+
+  /**
+   * This counts the number of remaining tokens in the string, with
+   * respect to the current delimiter set.
+   *
+   * @return the number of times <code>nextTokens()</code> will succeed
+   * @see #nextToken()
+   */
+  public int countTokens()
+  {
+    int count = 0;
+    int delimiterCount = 0;
+    boolean tokenFound = false; // Set when a non-delimiter is found
+    int tmpPos = pos;
+
+    // Note for efficiency, we count up the delimiters rather than check
+    // retDelims every time we encounter one.  That way, we can
+    // just do the conditional once at the end of the method
+    while (tmpPos < len)
+      {
+        if (delim.indexOf(str.charAt(tmpPos++)) >= 0)
+          {
+            if (tokenFound)
+              {
+                // Got to the end of a token
+                count++;
+                tokenFound = false;
+              }
+            delimiterCount++; // Increment for this delimiter
+          }
+        else
+          {
+            tokenFound = true;
+            // Get to the end of the token
+            while (tmpPos < len
+                   && delim.indexOf(str.charAt(tmpPos)) < 0)
+              ++tmpPos;
+          }
+      }
+
+    // Make sure to count the last token
+    if (tokenFound)
+      count++;
+
+    // if counting delmiters add them into the token count
+    return retDelims ? count + delimiterCount : count;
+  }
+} // class StringTokenizer