2238de654f
* java/lang/StringBuffer.java (toString): Don't mark buffer as shared. (insert(int,char[],int,int): New method. (delete): New method from Classpath. (deleteCharAt): Likewise. (substring): Likewise. (shared): No longer private. Added JavaDoc comments from Classpath. * java/lang/String.java (String(StringBuffer)): Ensure `buffer' is shared. From-SVN: r33809
668 lines
24 KiB
Java
668 lines
24 KiB
Java
// StringBuffer.java - Growable strings.
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/* Copyright (C) 1998, 1999, 2000 Red Hat
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package java.lang;
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import java.io.Serializable;
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/**
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* @author Tom Tromey <tromey@cygnus.com>
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* @date October 23, 1998.
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*/
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* Updated using online JDK 1.2 docs.
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* Believed complete and correct to JDK 1.2.
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* Merged with Classpath.
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*/
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/**
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* <code>StringBuffer</code> represents a changeable <code>String</code>.
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* It provides the operations required to modify the
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* <code>StringBuffer</code> including insert, replace, delete, append,
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* and reverse.
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* <P>
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*
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* <code>StringBuffer</code>s are variable-length in nature, so even if
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* you initialize them to a certain size, they can still grow larger than
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* that. <EM>Capacity</EM> indicates the number of characters the
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* <code>StringBuffer</code> can have in it before it has to grow (growing
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* the char array is an expensive operation involving <code>new</code>).
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* <P>
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*
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* Incidentally, the String operator "+" actually is turned into a
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* <code>StringBuffer</code> operation:
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* <BR>
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* <code>a + b</code>
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* <BR>
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* is the same as
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* <BR>
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* <code>new StringBuffer(a).append(b).toString()</code>.
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*
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* @implnote Classpath's StringBuffer is capable of sharing memory with
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* Strings for efficiency. This will help in two instances:
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* first, when a StringBuffer is created from a String but is
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* never changed, and second, when a StringBuffer is converted
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* to a String and the StringBuffer is not changed after that.
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*
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* @since JDK1.0
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* @author Paul Fisher
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* @author John Keiser
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* @author Tom Tromey
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* @see java.lang.String
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*/
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public final class StringBuffer implements Serializable
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{
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param bool the <code>boolean</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(boolean)
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*/
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public StringBuffer append (boolean bool)
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{
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return append (String.valueOf(bool));
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}
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/** Append the <code>char</code> to this <code>StringBuffer</code>.
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* @param c the <code>char</code> to append.
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* @return this <code>StringBuffer</code>.
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*/
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public synchronized StringBuffer append (char ch)
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{
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ensureCapacity_unsynchronized (count + 1);
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value[count++] = ch;
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return this;
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}
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param inum the <code>int</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(int)
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*/
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public StringBuffer append (int inum)
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{
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return append (String.valueOf(inum));
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}
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param lnum the <code>long</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(long)
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*/
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public StringBuffer append (long lnum)
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{
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return append (String.valueOf(lnum));
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}
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param fnum the <code>float</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(float)
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*/
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public StringBuffer append (float fnum)
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{
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return append (String.valueOf(fnum));
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}
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param dnum the <code>double</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(double)
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*/
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public StringBuffer append (double dnum)
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{
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return append (String.valueOf(dnum));
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}
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/** Append the <code>String</code> value of the argument to this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param obj the <code>Object</code> to convert and append.
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* @return this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(java.lang.Object)
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*/
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public StringBuffer append (Object obj)
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{
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return append (String.valueOf(obj));
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}
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/** Append the <code>String</code> to this <code>StringBuffer</code>.
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* @param str the <code>String</code> to append.
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* @return this <code>StringBuffer</code>.
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*/
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public synchronized StringBuffer append (String str)
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{
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if (str == null)
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str = "null";
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int len = str.length();
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ensureCapacity_unsynchronized (count + len);
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str.getChars(0, len, value, count);
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count += len;
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return this;
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}
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/** Append the <code>char</code> array to this <code>StringBuffer</code>.
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* @param data the <code>char[]</code> to append.
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* @return this <code>StringBuffer</code>.
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* @exception NullPointerException if <code>str</code> is <code>null</code>.
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*/
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public StringBuffer append (char[] data)
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{
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return append (data, 0, data.length);
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}
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/** Append the <code>char</code> array to this <code>StringBuffer</code>.
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* @param data the <code>char[]</code> to append.
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* @param offset the place to start grabbing characters from
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* <code>str</code>.
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* @param count the number of characters to get from <code>str</code>.
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* @return this <code>StringBuffer</code>.
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* @exception NullPointerException if <code>str</code> is <code>null</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> or
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* <code>offset+len</code> is out of range.
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*/
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public synchronized StringBuffer append (char[] data, int offset, int count)
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{
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ensureCapacity_unsynchronized (this.count + count);
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System.arraycopy(data, offset, value, this.count, count);
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this.count += count;
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return this;
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}
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/** Get the total number of characters this <code>StringBuffer</code>
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* can support before it must be grown. Not to be confused with
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* <em>length</em>.
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* @return the capacity of this <code>StringBuffer</code>
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* @see #length()
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* @see #ensureCapacity(int)
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*/
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public int capacity ()
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{
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return value.length;
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}
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/** Get the character at the specified index.
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* @param index the index of the character to get, starting at 0.
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* @return the character at the specified index.
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* @exception IndexOutOfBoundsException if the desired character index
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* is not between 0 and length() - 1 (inclusive).
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*/
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public synchronized char charAt (int index)
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{
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if (index >= count)
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throw new StringIndexOutOfBoundsException (index);
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return value[index];
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}
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/** Delete characters from this <code>StringBuffer</code>.
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* <code>delete(10, 12)</code> will delete 10 and 11, but not 12.
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* @param start the first character to delete.
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* @param end the index after the last character to delete.
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* @return this <code>StringBuffer</code>.
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* @exception StringIndexOutOfBoundsException if <code>start</code>
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* or <code>end-1</code> are out of bounds, or if
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* <code>start > end</code>.
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*/
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public synchronized StringBuffer delete (int start, int end)
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{
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if (start < 0 || start > count || start > end)
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throw new StringIndexOutOfBoundsException (start);
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if (end > count)
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end = count;
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// This will unshare if required.
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ensureCapacity_unsynchronized (count);
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count -= (end - start);
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System.arraycopy (value, end - 1, value, start, end - start);
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return this;
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}
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/** Delete a character from this <code>StringBuffer</code>.
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* @param index the index of the character to delete.
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* @return this <code>StringBuffer</code>.
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* @exception StringIndexOutOfBoundsException if <code>index</code>
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* is out of bounds.
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*/
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public StringBuffer deleteCharAt(int index)
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{
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return delete (index, index + 1);
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}
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/** Increase the capacity of this <code>StringBuffer</code>.
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* This will ensure that an expensive growing operation will not occur
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* until <code>minimumCapacity</code> is reached.
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* If the capacity is actually already greater than <code>minimumCapacity</code>
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* @param minimumCapacity the new capacity.
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* @see #capacity()
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*/
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public synchronized void ensureCapacity (int minimumCapacity)
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{
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if (shared || minimumCapacity > value.length)
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{
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// We don't want to make a larger vector when `shared' is
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// set. If we do, then setLength becomes very inefficient
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// when repeatedly reusing a StringBuffer in a loop.
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int max = (minimumCapacity > value.length
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? value.length*2+2
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: value.length);
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minimumCapacity = (minimumCapacity < max ? max : minimumCapacity);
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char[] nb = new char[minimumCapacity];
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System.arraycopy(value, 0, nb, 0, count);
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value = nb;
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shared = false;
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}
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}
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// ensureCapacity is used by several synchronized methods in StringBuffer.
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// There's no need to synchronize again.
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private void ensureCapacity_unsynchronized (int minimumCapacity)
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{
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if (shared || minimumCapacity > value.length)
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{
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// We don't want to make a larger vector when `shared' is
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// set. If we do, then setLength becomes very inefficient
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// when repeatedly reusing a StringBuffer in a loop.
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int max = (minimumCapacity > value.length
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? value.length*2+2
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: value.length);
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minimumCapacity = (minimumCapacity < max ? max : minimumCapacity);
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char[] nb = new char[minimumCapacity];
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System.arraycopy(value, 0, nb, 0, count);
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value = nb;
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shared = false;
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}
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}
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/** Get the specified array of characters.
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* The characters will be copied into the array you pass in.
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* @param srcOffset the index to start copying from in the
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* <code>StringBuffer</code>.
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* @param srcEnd the number of characters to copy.
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* @param dst the array to copy into.
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* @param dstOffset the index to start copying into <code>dst</code>.
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* @exception NullPointerException if dst is null.
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* @exception IndexOutOfBoundsException if any source or target
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* indices are out of range.
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* @see java.lang.System#arrayCopy(java.lang.Object,int,java.lang.Object,int,int)
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*/
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public synchronized void getChars (int srcOffset, int srcEnd,
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char[] dst, int dstOffset)
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{
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if (srcOffset < 0 || srcOffset > srcEnd)
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throw new StringIndexOutOfBoundsException (srcOffset);
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int todo = srcEnd - srcOffset;
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if (srcEnd > count || dstOffset + todo > count)
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throw new StringIndexOutOfBoundsException (srcEnd);
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System.arraycopy(value, srcOffset, dst, dstOffset, todo);
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param bool the <code>boolean</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(boolean)
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*/
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public StringBuffer insert (int offset, boolean bool)
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{
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return insert (offset, bool ? "true" : "false");
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}
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/** Insert the <code>char</code> argument into this <code>StringBuffer</code>.
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* @param offset the place to insert.
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* @param ch the <code>char</code> to insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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*/
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public synchronized StringBuffer insert (int offset, char ch)
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{
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if (offset < 0 || offset > count)
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throw new StringIndexOutOfBoundsException (offset);
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ensureCapacity_unsynchronized (count+1);
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System.arraycopy(value, offset, value, offset+1, count-offset);
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value[offset] = ch;
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count++;
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return this;
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param inum the <code>int</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(int)
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*/
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public StringBuffer insert (int offset, int inum)
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{
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return insert (offset, String.valueOf(inum));
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param lnum the <code>long</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(long)
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*/
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public StringBuffer insert (int offset, long lnum)
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{
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return insert (offset, String.valueOf(lnum));
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param fnum the <code>float</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(float)
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*/
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public StringBuffer insert (int offset, float fnum)
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{
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return insert (offset, String.valueOf(fnum));
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param dnum the <code>double</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(double)
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*/
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public StringBuffer insert (int offset, double dnum)
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{
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return insert (offset, String.valueOf(dnum));
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}
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/** Insert the <code>String</code> value of the argument into this <code>StringBuffer</code>.
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* Uses <code>String.valueOf()</code> to convert to
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* <code>String</code>.
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* @param offset the place to insert.
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* @param obj the <code>Object</code> to convert and insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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* @see java.lang.String#valueOf(java.lang.Object)
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*/
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public StringBuffer insert (int offset, Object obj)
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{
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return insert (offset, String.valueOf(obj));
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}
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/** Insert the <code>String</code> argument into this <code>StringBuffer</code>.
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* @param offset the place to insert.
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* @param str the <code>String</code> to insert.
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* @return this <code>StringBuffer</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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*/
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public synchronized StringBuffer insert (int offset, String str)
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{
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if (offset < 0 || offset > count)
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throw new StringIndexOutOfBoundsException (offset);
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// Note that using `null' is from JDK 1.2.
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if (str == null)
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str = "null";
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int len = str.length();
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ensureCapacity_unsynchronized (count+len);
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System.arraycopy(value, offset, value, offset+len, count-offset);
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str.getChars(0, len, value, offset);
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count += len;
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return this;
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}
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/** Insert the <code>char[]</code> argument into this
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* <code>StringBuffer</code>.
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* @param offset the place to insert.
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* @param data the <code>char[]</code> to insert.
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* @return this <code>StringBuffer</code>.
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* @exception NullPointerException if <code>data</code> is
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* <code>null</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range for this <code>StringBuffer</code>.
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*/
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public StringBuffer insert (int offset, char[] data)
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{
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return insert (offset, data, 0, data.length);
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}
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/** Insert the <code>char[]</code> argument into this
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* <code>StringBuffer</code>.
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* @param offset the place to insert.
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* @param str the <code>char[]</code> to insert.
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* @param str_offset the index in <code>str</code> to start inserting
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* from.
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* @param len the number of characters to insert.
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* @return this <code>StringBuffer</code>.
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* @exception NullPointerException if <code>str</code> is <code>null</code>.
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* @exception IndexOutOfBoundsException if <code>offset</code> is out
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* of range, for this <code>StringBuffer</code>, or if
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* <code>str_offset</code> or <code>str_offset+len</code>
|
|
* are out of range for <code>str</code>.
|
|
*/
|
|
public synchronized StringBuffer insert(int offset, char[] str,
|
|
int str_offset, int len)
|
|
{
|
|
if (offset < 0 || offset > count)
|
|
throw new StringIndexOutOfBoundsException (offset);
|
|
if (len < 0)
|
|
throw new StringIndexOutOfBoundsException (len);
|
|
if (str_offset < 0 || str_offset + len > str.length)
|
|
throw new StringIndexOutOfBoundsException (str_offset);
|
|
ensureCapacity_unsynchronized (count + len);
|
|
System.arraycopy(value, offset, value, offset + len, count - offset);
|
|
System.arraycopy(str, str_offset, value, offset, len);
|
|
count += len;
|
|
return this;
|
|
}
|
|
|
|
/** Get the length of the <code>String</code> this
|
|
* <code>StringBuffer</code> would create. Not to be confused with the
|
|
* <em>capacity</em> of the <code>StringBuffer</code>.
|
|
* @return the length of this <code>StringBuffer</code>.
|
|
* @see #capacity()
|
|
* @see #setLength()
|
|
*/
|
|
public int length ()
|
|
{
|
|
return count;
|
|
}
|
|
|
|
/** Delete a character from this <code>StringBuffer</code>.
|
|
* @param index the index of the character to delete.
|
|
* @return this <code>StringBuffer</code>.
|
|
* @exception StringIndexOutOfBoundsException if <code>index</code>
|
|
* is out of bounds.
|
|
*/
|
|
public synchronized StringBuffer replace (int start, int end, String str)
|
|
{
|
|
// FIXME: this is inefficient.
|
|
delete (start, end);
|
|
return insert (start, str);
|
|
}
|
|
|
|
/** Reverse the characters in this StringBuffer.
|
|
* @return this <code>StringBuffer</code>.
|
|
*/
|
|
public synchronized StringBuffer reverse ()
|
|
{
|
|
for (int i = 0; i < count / 2; ++i)
|
|
{
|
|
char c = value[i];
|
|
value[i] = value[count - i - 1];
|
|
value[count - i - 1] = c;
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/** Set the character at the specified index.
|
|
* @param index the index of the character to set starting at 0.
|
|
* @param ch the value to set that character to.
|
|
* @exception IndexOutOfBoundsException if the specified character
|
|
* index is not between 0 and length() - 1 (inclusive).
|
|
*/
|
|
public synchronized void setCharAt (int index, char ch)
|
|
{
|
|
if (index < 0 || index >= count)
|
|
throw new StringIndexOutOfBoundsException (index);
|
|
// Call ensureCapacity to enforce copy-on-write.
|
|
ensureCapacity_unsynchronized (count);
|
|
value[index] = ch;
|
|
}
|
|
|
|
/** Set the length of this StringBuffer.
|
|
* <P>
|
|
* If the new length is greater than the current length, all the new
|
|
* characters are set to '\0'.
|
|
* <P>
|
|
* If the new length is less than the current length, the first
|
|
* <code>newLength</code> characters of the old array will be
|
|
* @param newLength the new length
|
|
* @exception IndexOutOfBoundsException if the new length is
|
|
* negative.
|
|
* @see #length()
|
|
*/
|
|
public synchronized void setLength (int newLength)
|
|
{
|
|
if (newLength < 0)
|
|
throw new StringIndexOutOfBoundsException (newLength);
|
|
|
|
ensureCapacity_unsynchronized (newLength);
|
|
for (int i = count; i < newLength; ++i)
|
|
value[i] = '\0';
|
|
count = newLength;
|
|
}
|
|
|
|
/** Create a new StringBuffer with default capacity 16.
|
|
* @see JLS 20.13.1
|
|
*/
|
|
public StringBuffer ()
|
|
{
|
|
this (DEFAULT_CAPACITY);
|
|
}
|
|
|
|
/** Create an empty <code>StringBuffer</code> with the specified initial capacity.
|
|
* @param capacity the initial capacity.
|
|
*/
|
|
public StringBuffer (int capacity)
|
|
{
|
|
count = 0;
|
|
value = new char[capacity];
|
|
shared = false;
|
|
}
|
|
|
|
/** Create a new <code>StringBuffer</code> with the characters in the specified <code>String</code>.
|
|
* Initial capacity will be the size of the String plus 16.
|
|
* @param str the <code>String</code> to make a <code>StringBuffer</code> out of.
|
|
* @XXX optimize for sharing.
|
|
*/
|
|
public StringBuffer (String str)
|
|
{
|
|
// The documentation is not clear, but experimentation with
|
|
// other implementations indicates that StringBuffer(null)
|
|
// should throw a NullPointerException.
|
|
count = str.length();
|
|
// JLS: The initial capacity of the string buffer is 16 plus the
|
|
// length of the argument string.
|
|
value = new char[count + 16];
|
|
str.getChars(0, count, value, 0);
|
|
shared = false;
|
|
}
|
|
|
|
/**
|
|
* Creates a substring of this StringBuffer, starting at a specified index
|
|
* and ending at the end of this StringBuffer.
|
|
*
|
|
* @param beginIndex index to start substring (base 0)
|
|
*
|
|
* @return new String which is a substring of this StringBuffer
|
|
*
|
|
* @exception StringIndexOutOfBoundsException
|
|
* if (beginIndex < 0 || beginIndex > this.length())
|
|
*/
|
|
public String substring (int beginIndex)
|
|
{
|
|
return substring (beginIndex, count);
|
|
}
|
|
|
|
/**
|
|
* Creates a substring of this StringBuffer, starting at a specified index
|
|
* and ending at one character before a specified index.
|
|
*
|
|
* @param beginIndex index to start substring (base 0)
|
|
* @param endIndex index after the last character to be
|
|
* copied into the substring
|
|
*
|
|
* @return new String which is a substring of this StringBuffer
|
|
*
|
|
* @exception StringIndexOutOfBoundsException
|
|
* if (beginIndex < 0 || endIndex > this.length() || beginIndex > endIndex)
|
|
*/
|
|
public synchronized String substring (int beginIndex, int endIndex)
|
|
{
|
|
if (beginIndex < 0 || endIndex > count || beginIndex > endIndex)
|
|
throw new StringIndexOutOfBoundsException ();
|
|
// FIXME: for libgcj it would be possible, and more efficient, to
|
|
// enable sharing here.
|
|
return new String (value, beginIndex, endIndex - beginIndex);
|
|
}
|
|
|
|
/** Convert this <code>StringBuffer</code> to a <code>String</code>.
|
|
* @return the characters in this StringBuffer
|
|
*/
|
|
public String toString ()
|
|
{
|
|
// Note: in libgcj this causes the StringBuffer to be shared. In
|
|
// Classpath it does not.
|
|
return new String (this);
|
|
}
|
|
|
|
// Index of next available character. Note that this has
|
|
// permissions set this way so that String can get the value.
|
|
int count;
|
|
|
|
// The buffer. Note that this has permissions set this way so that
|
|
// String can get the value.
|
|
char[] value;
|
|
|
|
// True if we need to copy the buffer before writing to it again.
|
|
// FIXME: JDK 1.2 doesn't specify this. The new buffer-growing
|
|
// semantics make this less useful in that case, too. Note that
|
|
// this has permissions set this way so that String can get the
|
|
// value.
|
|
boolean shared;
|
|
|
|
static final long serialVersionUID = 3388685877147921107L;
|
|
private final static int DEFAULT_CAPACITY = 16; // JLS 20.13.1
|
|
}
|