/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program 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 version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package java.lang;
import com.sun.cldchi.jvm.JVM;
/**
* A string buffer implements a mutable sequence of characters.
* A string buffer is like a {@link String}, but can be modified. At any
* point in time it contains some particular sequence of characters, but
* the length and content of the sequence can be changed through certain
* method calls.
* <p>
* String buffers are safe for use by multiple threads. The methods
* are synchronized where necessary so that all the operations on any
* particular instance behave as if they occur in some serial order
* that is consistent with the order of the method calls made by each of
* the individual threads involved.
* <p>
* String buffers are used by the compiler to implement the binary
* string concatenation operator <code>+</code>. For example, the code:
* <p><blockquote><pre>
* x = "a" + 4 + "c"
* </pre></blockquote><p>
* is compiled to the equivalent of:
* <p><blockquote><pre>
* x = new StringBuffer().append("a").append(4).append("c")
* .toString()
* </pre></blockquote>
* which creates a new string buffer (initially empty), appends the string
* representation of each operand to the string buffer in turn, and then
* converts the contents of the string buffer to a string. Overall, this avoids
* creating many temporary strings.
* <p>
* The principal operations on a <code>StringBuffer</code> are the
* <code>append</code> and <code>insert</code> methods, which are
* overloaded so as to accept data of any type. Each effectively
* converts a given datum to a string and then appends or inserts the
* characters of that string to the string buffer. The
* <code>append</code> method always adds these characters at the end
* of the buffer; the <code>insert</code> method adds the characters at
* a specified point.
* <p>
* For example, if <code>z</code> refers to a string buffer object
* whose current contents are "<code>start</code>", then
* the method call <code>z.append("le")</code> would cause the string
* buffer to contain "<code>startle</code>", whereas
* <code>z.insert(4, "le")</code> would alter the string buffer to
* contain "<code>starlet</code>".
* <p>
* In general, if sb refers to an instance of a <code>StringBuffer</code>,
* then <code>sb.append(x)</code> has the same effect as
* <code>sb.insert(sb.length(), x)</code>.
* <p>
* Every string buffer has a capacity. As long as the length of the
* character sequence contained in the string buffer does not exceed
* the capacity, it is not necessary to allocate a new internal
* buffer array. If the internal buffer overflows, it is
* automatically made larger.
*
* @version 1.60, 12/04/99 (CLDC 1.0, Spring 2000)
* @see java.io.ByteArrayOutputStream
* @see java.lang.String
* @since JDK1.0
*/
public final class StringBuffer {
/**
* The value is used for character storage.
*
* @serial
*/
private char value[];
/**
* The count is the number of characters in the buffer.
*
* @serial
*/
private int count;
/**
* A flag indicating whether the buffer is shared
*
* @serial
*/
private boolean shared;
/**
* Constructs a string buffer with no characters in it and an
* initial capacity of 16 characters.
*/
public StringBuffer() {
value = new char[16];
}
/**
* Constructs a string buffer with no characters in it and an
* initial capacity specified by the <code>length</code> argument.
*
* @param length the initial capacity.
* @exception NegativeArraySizeException if the <code>length</code>
* argument is less than <code>0</code>.
*/
public StringBuffer(int length) {
value = new char[length];
}
/**
* Constructs a string buffer so that it represents the same
* sequence of characters as the string argument; in other
* words, the initial contents of the string buffer is a copy of the
* argument string. The initial capacity of the string buffer is
* <code>16</code> plus the length of the string argument.
*
* @param str the initial contents of the buffer.
*/
public StringBuffer(String str) {
this(str.length() + 16);
append(str);
}
/**
* Returns the length (character count) of this string buffer.
*
* @return the length of the sequence of characters currently
* represented by this string buffer.
*/
public int length() {
return count;
}
/**
* Returns the current capacity of the String buffer. The capacity
* is the amount of storage available for newly inserted
* characters; beyond which an allocation will occur.
*
* @return the current capacity of this string buffer.
*/
public int capacity() {
return value.length;
}
/**
* Copies the buffer value. This is normally only called when shared
* is true. It should only be called from a synchronized method.
*/
private final void copy() {
char newValue[] = new char[value.length];
JVM.unchecked_char_arraycopy(value, 0, newValue, 0, count);
value = newValue;
shared = false;
}
/**
* Ensures that the capacity of the buffer is at least equal to the
* specified minimum.
* If the current capacity of this string buffer is less than the
* argument, then a new internal buffer is allocated with greater
* capacity. The new capacity is the larger of:
* <ul>
* <li>The <code>minimumCapacity</code> argument.
* <li>Twice the old capacity, plus <code>2</code>.
* </ul>
* If the <code>minimumCapacity</code> argument is nonpositive, this
* method takes no action and simply returns.
*
* @param minimumCapacity the minimum desired capacity.
*/
public synchronized void ensureCapacity(int minimumCapacity) {
if (minimumCapacity > value.length) {
expandCapacity(minimumCapacity);
}
}
/**
* This implements the expansion semantics of ensureCapacity but is
* unsynchronized for use internally by methods which are already
* synchronized.
*
* @see java.lang.StringBuffer#ensureCapacity(int)
*/
private void expandCapacity(int minimumCapacity) {
int newCapacity = (value.length + 1) * 2;
if (newCapacity < 0) {
newCapacity = Integer.MAX_VALUE;
} else if (minimumCapacity > newCapacity) {
newCapacity = minimumCapacity;
}
char newValue[] = new char[newCapacity];
JVM.unchecked_char_arraycopy(value, 0, newValue, 0, count);
value = newValue;
shared = false;
}
/**
* Sets the length of this String buffer.
* This string buffer is altered to represent a new character sequence
* whose length is specified by the argument. For every nonnegative
* index <i>k</i> less than <code>newLength</code>, the character at
* index <i>k</i> in the new character sequence is the same as the
* character at index <i>k</i> in the old sequence if <i>k</i> is less
* than the length of the old character sequence; otherwise, it is the
* null character <code>'\u0000'</code>.
*
* In other words, if the <code>newLength</code> argument is less than
* the current length of the string buffer, the string buffer is
* truncated to contain exactly the number of characters given by the
* <code>newLength</code> argument.
* <p>
* If the <code>newLength</code> argument is greater than or equal
* to the current length, sufficient null characters
* (<code>'\u0000'</code>) are appended to the string buffer so that
* length becomes the <code>newLength</code> argument.
* <p>
* The <code>newLength</code> argument must be greater than or equal
* to <code>0</code>.
*
* @param newLength the new length of the buffer.
* @exception IndexOutOfBoundsException if the
* <code>newLength</code> argument is negative.
* @see java.lang.StringBuffer#length()
*/
public synchronized void setLength(int newLength) {
if (newLength < 0) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped newLength
/* #endif */
);
}
if (newLength > value.length) {
expandCapacity(newLength);
}
if (count < newLength) {
if (shared) copy();
for (; count < newLength; count++) {
value[count] = '\0';
}
} else {
count = newLength;
if (shared) {
if (newLength > 0) {
copy();
} else {
// If newLength is zero, assume the StringBuffer is being
// stripped for reuse; Make new buffer of default size
value = new char[16];
shared = false;
}
}
}
}
/**
* The specified character of the sequence currently represented by
* the string buffer, as indicated by the <code>index</code> argument,
* is returned. The first character of a string buffer is at index
* <code>0</code>, the next at index <code>1</code>, and so on, for
* array indexing.
* <p>
* The index argument must be greater than or equal to
* <code>0</code>, and less than the length of this string buffer.
*
* @param index the index of the desired character.
* @return the character at the specified index of this string buffer.
* @exception IndexOutOfBoundsException if <code>index</code> is
* negative or greater than or equal to <code>length()</code>.
* @see java.lang.StringBuffer#length()
*/
public synchronized char charAt(int index) {
if ((index < 0) || (index >= count)) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped index
/* #endif */
);
}
return value[index];
}
/**
* Characters are copied from this string buffer into the
* destination character array <code>dst</code>. The first character to
* be copied is at index <code>srcBegin</code>; the last character to
* be copied is at index <code>srcEnd-1</code>. The total number of
* characters to be copied is <code>srcEnd-srcBegin</code>. The
* characters are copied into the subarray of <code>dst</code> starting
* at index <code>dstBegin</code> and ending at index:
* <p><blockquote><pre>
* dstbegin + (srcEnd-srcBegin) - 1
* </pre></blockquote>
*
* @param srcBegin start copying at this offset in the string buffer.
* @param srcEnd stop copying at this offset in the string buffer.
* @param dst the array to copy the data into.
* @param dstBegin offset into <code>dst</code>.
* @exception NullPointerException if <code>dst</code> is
* <code>null</code>.
* @exception IndexOutOfBoundsException if any of the following is true:
* <ul>
* <li><code>srcBegin</code> is negative
* <li><code>dstBegin</code> is negative
* <li>the <code>srcBegin</code> argument is greater than
* the <code>srcEnd</code> argument.
* <li><code>srcEnd</code> is greater than
* <code>this.length()</code>, the current length of this
* string buffer.
* <li><code>dstBegin+srcEnd-srcBegin</code> is greater than
* <code>dst.length</code>
* </ul>
*/
public synchronized void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin) {
if (srcBegin < 0) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped srcBegin
/* #endif */
);
}
if ((srcEnd < 0) || (srcEnd > count)) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped srcEnd
/* #endif */
);
}
if (srcBegin > srcEnd) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped "srcBegin > srcEnd"
/* #endif */
);
}
// NOTE: dst not checked, cannot use unchecked arraycopy
System.arraycopy(value, srcBegin, dst, dstBegin, srcEnd - srcBegin);
}
/**
* The character at the specified index of this string buffer is set
* to <code>ch</code>. The string buffer is altered to represent a new
* character sequence that is identical to the old character sequence,
* except that it contains the character <code>ch</code> at position
* <code>index</code>.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than the length of this string buffer.
*
* @param index the index of the character to modify.
* @param ch the new character.
* @exception IndexOutOfBoundsException if <code>index</code> is
* negative or greater than or equal to <code>length()</code>.
* @see java.lang.StringBuffer#length()
*/
public synchronized void setCharAt(int index, char ch) {
if ((index < 0) || (index >= count)) {
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped index
/* #endif */
);
}
if (shared) copy();
value[index] = ch;
}
/**
* Appends the string representation of the <code>Object</code>
* argument to this string buffer.
* <p>
* The argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then appended to this string buffer.
*
* @param obj an <code>Object</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @see java.lang.String#valueOf(java.lang.Object)
* @see java.lang.StringBuffer#append(java.lang.String)
*/
public synchronized StringBuffer append(Object obj) {
return append(String.valueOf(obj));
}
/**
* Appends the string to this string buffer.
* <p>
* The characters of the <code>String</code> argument are appended, in
* order, to the contents of this string buffer, increasing the
* length of this string buffer by the length of the argument.
* If <code>str</code> is <code>null</code>, then the four characters
* <code>"null"</code> are appended to this string buffer.
* <p>
* Let <i>n</i> be the length of the old character sequence, the one
* contained in the string buffer just prior to execution of the
* <code>append</code> method. Then the character at index <i>k</i> in
* the new character sequence is equal to the character at index <i>k</i>
* in the old character sequence, if <i>k</i> is less than <i>n</i>;
* otherwise, it is equal to the character at index <i>k-n</i> in the
* argument <code>str</code>.
*
* @param str a string.
* @return a reference to this <code>StringBuffer</code>.
*/
public synchronized StringBuffer append(String str) {
if (str == null) {
str = String.valueOf(str);
}
int len = str.length();
int newcount = count + len;
if (newcount > value.length)
expandCapacity(newcount);
str.getChars(0, len, value, count);
count = newcount;
return this;
}
/**
* Appends the string representation of the <code>char</code> array
* argument to this string buffer.
* <p>
* The characters of the array argument are appended, in order, to
* the contents of this string buffer. The length of this string
* buffer increases by the length of the argument.
* <p>
* The overall effect is exactly as if the argument were converted to
* a string by the method {@link String#valueOf(char[])} and the
* characters of that string were then {@link #append(String) appended}
* to this <code>StringBuffer</code> object.
*
* @param str the characters to be appended.
* @return a reference to this <code>StringBuffer</code> object.
*/
public synchronized StringBuffer append(char str[]) {
int len = str.length;
int newcount = count + len;
if (newcount > value.length)
expandCapacity(newcount);
JVM.unchecked_char_arraycopy(str, 0, value, count, len);
count = newcount;
return this;
}
/**
* Appends the string representation of a subarray of the
* <code>char</code> array argument to this string buffer.
* <p>
* Characters of the character array <code>str</code>, starting at
* index <code>offset</code>, are appended, in order, to the contents
* of this string buffer. The length of this string buffer increases
* by the value of <code>len</code>.
* <p>
* The overall effect is exactly as if the arguments were converted to
* a string by the method {@link String#valueOf(char[],int,int)} and the
* characters of that string were then {@link #append(String) appended}
* to this <code>StringBuffer</code> object.
*
* @param str the characters to be appended.
* @param offset the index of the first character to append.
* @param len the number of characters to append.
* @return a reference to this <code>StringBuffer</code> object.
*/
public synchronized StringBuffer append(char str[], int offset, int len) {
int newcount = count + len;
if (newcount > value.length)
expandCapacity(newcount);
// NOTE: str and offset not checked, cannot use unchecked arraycopy
System.arraycopy(str, offset, value, count, len);
count = newcount;
return this;
}
/**
* Appends the string representation of the <code>boolean</code>
* argument to the string buffer.
* <p>
* The argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then appended to this string buffer.
*
* @param b a <code>boolean</code>.
* @return a reference to this <code>StringBuffer</code>.
* @see java.lang.String#valueOf(boolean)
* @see java.lang.StringBuffer#append(java.lang.String)
*/
public StringBuffer append(boolean b) {
return append(String.valueOf(b));
}
/**
* Appends the string representation of the <code>char</code>
* argument to this string buffer.
* <p>
* The argument is appended to the contents of this string buffer.
* The length of this string buffer increases by <code>1</code>.
* <p>
* The overall effect is exactly as if the argument were converted to
* a string by the method {@link String#valueOf(char)} and the character
* in that string were then {@link #append(String) appended} to this
* <code>StringBuffer</code> object.
*
* @param c a <code>char</code>.
* @return a reference to this <code>StringBuffer</code> object.
*/
public synchronized StringBuffer append(char c) {
int newcount = count + 1;
if (newcount > value.length)
expandCapacity(newcount);
value[count++] = c;
return this;
}
/**
* Appends the string representation of the <code>int</code>
* argument to this string buffer.
* <p>
* The argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then appended to this string buffer.
*
* @param i an <code>int</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @see java.lang.String#valueOf(int)
* @see java.lang.StringBuffer#append(java.lang.String)
*/
public StringBuffer append(int i) {
return append(String.valueOf(i));
}
/**
* Appends the string representation of the <code>long</code>
* argument to this string buffer.
* <p>
* The argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then appended to this string buffer.
*
* @param l a <code>long</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @see java.lang.String#valueOf(long)
* @see java.lang.StringBuffer#append(java.lang.String)
*/
public StringBuffer append(long l) {
return append(String.valueOf(l));
}
/**
* Removes the characters in a substring of this <code>StringBuffer</code>.
* The substring begins at the specified <code>start</code> and extends to
* the character at index <code>end - 1</code> or to the end of the
* <code>StringBuffer</code> if no such character exists. If
* <code>start</code> is equal to <code>end</code>, no changes are made.
*
* @param start The beginning index, inclusive.
* @param end The ending index, exclusive.
* @return This string buffer.
* @exception StringIndexOutOfBoundsException if <code>start</code>
* is negative, greater than <code>length()</code>, or
* greater than <code>end</code>.
* @since 1.2
*/
public synchronized StringBuffer delete(int start, int end) {
if (start < 0)
throw new StringIndexOutOfBoundsException(
/* #ifdef VERBOSE_EXCEPTIONS */
/// skipped start
/* #endif */
);
if (end > count)
end = count;
if (start > end)
throw new StringIndexOutOfBoundsException();
int len = end - start;
if (len > 0) {
if (shared)
copy();
JVM.unchecked_char_arraycopy(value, start+len,
value, start, count-end);
count -= len;
}
return this;
}
/**
* Removes the character at the specified position in this
* <code>StringBuffer</code> (shortening the <code>StringBuffer</code>
* by one character).
*
* @param index Index of character to remove
* @return This string buffer.
* @exception StringIndexOutOfBoundsException if the <code>index</code>
* is negative or greater than or equal to
* <code>length()</code>.
* @since 1.2
*/
public synchronized StringBuffer deleteCharAt(int index) {
if ((index < 0) || (index >= count))
throw new StringIndexOutOfBoundsException();
if (shared)
copy();
JVM.unchecked_char_arraycopy(value, index+1,
value, index, count-index-1);
count--;
return this;
}
/**
* Inserts the string representation of the <code>Object</code>
* argument into this string buffer.
* <p>
* The second argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then inserted into this string buffer at the indicated
* offset.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param obj an <code>Object</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
* @see java.lang.String#valueOf(java.lang.Object)
* @see java.lang.StringBuffer#insert(int, java.lang.String)
* @see java.lang.StringBuffer#length()
*/
public synchronized StringBuffer insert(int offset, Object obj) {
return insert(offset, String.valueOf(obj));
}
/**
* Inserts the string into this string buffer.
* <p>
* The characters of the <code>String</code> argument are inserted, in
* order, into this string buffer at the indicated offset, moving up any
* characters originally above that position and increasing the length
* of this string buffer by the length of the argument. If
* <code>str</code> is <code>null</code>, then the four characters
* <code>"null"</code> are inserted into this string buffer.
* <p>
* The character at index <i>k</i> in the new character sequence is
* equal to:
* <ul>
* <li>the character at index <i>k</i> in the old character sequence, if
* <i>k</i> is less than <code>offset</code>
* <li>the character at index <i>k</i><code>-offset</code> in the
* argument <code>str</code>, if <i>k</i> is not less than
* <code>offset</code> but is less than <code>offset+str.length()</code>
* <li>the character at index <i>k</i><code>-str.length()</code> in the
* old character sequence, if <i>k</i> is not less than
* <code>offset+str.length()</code>
* </ul><p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param str a string.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
* @see java.lang.StringBuffer#length()
*/
public synchronized StringBuffer insert(int offset, String str) {
if ((offset < 0) || (offset > count)) {
throw new StringIndexOutOfBoundsException();
}
if (str == null) {
str = String.valueOf(str);
}
int len = str.length();
int newcount = count + len;
if (newcount > value.length)
expandCapacity(newcount);
else if (shared)
copy();
JVM.unchecked_char_arraycopy(value, offset,
value, offset + len, count - offset);
str.getChars(0, len, value, offset);
count = newcount;
return this;
}
/**
* Inserts the string representation of the <code>char</code> array
* argument into this string buffer.
* <p>
* The characters of the array argument are inserted into the
* contents of this string buffer at the position indicated by
* <code>offset</code>. The length of this string buffer increases by
* the length of the argument.
* <p>
* The overall effect is exactly as if the argument were converted to
* a string by the method {@link String#valueOf(char[])} and the
* characters of that string were then
* {@link #insert(int,String) inserted} into this
* <code>StringBuffer</code> object at the position indicated by
* <code>offset</code>.
*
* @param offset the offset.
* @param str a character array.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
*/
public synchronized StringBuffer insert(int offset, char str[]) {
if ((offset < 0) || (offset > count)) {
throw new StringIndexOutOfBoundsException();
}
int len = str.length;
int newcount = count + len;
if (newcount > value.length)
expandCapacity(newcount);
else if (shared)
copy();
JVM.unchecked_char_arraycopy(value, offset,
value, offset + len, count - offset);
JVM.unchecked_char_arraycopy(str, 0, value, offset, len);
count = newcount;
return this;
}
/**
* Inserts the string representation of the <code>boolean</code>
* argument into this string buffer.
* <p>
* The second argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then inserted into this string buffer at the indicated
* offset.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param b a <code>boolean</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
* @see java.lang.String#valueOf(boolean)
* @see java.lang.StringBuffer#insert(int, java.lang.String)
* @see java.lang.StringBuffer#length()
*/
public StringBuffer insert(int offset, boolean b) {
return insert(offset, String.valueOf(b));
}
/**
* Inserts the string representation of the <code>char</code>
* argument into this string buffer.
* <p>
* The second argument is inserted into the contents of this string
* buffer at the position indicated by <code>offset</code>. The length
* of this string buffer increases by one.
* <p>
* The overall effect is exactly as if the argument were converted to
* a string by the method {@link String#valueOf(char)} and the character
* in that string were then {@link #insert(int, String) inserted} into
* this <code>StringBuffer</code> object at the position indicated by
* <code>offset</code>.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param c a <code>char</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @exception IndexOutOfBoundsException if the offset is invalid.
* @see java.lang.StringBuffer#length()
*/
public synchronized StringBuffer insert(int offset, char c) {
int newcount = count + 1;
if (newcount > value.length)
expandCapacity(newcount);
else if (shared)
copy();
// NOTE: offset not checked, cannot use unchecked arraycopy
System.arraycopy(value, offset, value, offset + 1, count - offset);
value[offset] = c;
count = newcount;
return this;
}
/**
* Inserts the string representation of the second <code>int</code>
* argument into this string buffer.
* <p>
* The second argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then inserted into this string buffer at the indicated
* offset.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param i an <code>int</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
* @see java.lang.String#valueOf(int)
* @see java.lang.StringBuffer#insert(int, java.lang.String)
* @see java.lang.StringBuffer#length()
*/
public StringBuffer insert(int offset, int i) {
return insert(offset, String.valueOf(i));
}
/**
* Inserts the string representation of the <code>long</code>
* argument into this string buffer.
* <p>
* The second argument is converted to a string as if by the method
* <code>String.valueOf</code>, and the characters of that
* string are then inserted into this string buffer at the position
* indicated by <code>offset</code>.
* <p>
* The offset argument must be greater than or equal to
* <code>0</code>, and less than or equal to the length of this
* string buffer.
*
* @param offset the offset.
* @param l a <code>long</code>.
* @return a reference to this <code>StringBuffer</code> object.
* @exception StringIndexOutOfBoundsException if the offset is invalid.
* @see java.lang.String#valueOf(long)
* @see java.lang.StringBuffer#insert(int, java.lang.String)
* @see java.lang.StringBuffer#length()
*/
public StringBuffer insert(int offset, long l) {
return insert(offset, String.valueOf(l));
}
/**
* The character sequence contained in this string buffer is
* replaced by the reverse of the sequence.
* <p>
* Let <i>n</i> be the length of the old character sequence, the one
* contained in the string buffer just prior to execution of the
* <code>reverse</code> method. Then the character at index <i>k</i> in
* the new character sequence is equal to the character at index
* <i>n-k-1</i> in the old character sequence.
*
* @return a reference to this <code>StringBuffer</code> object..
* @since JDK1.0.2
*/
public synchronized StringBuffer reverse() {
if (shared) copy();
int n = count - 1;
for (int j = (n-1) >> 1; j >= 0; --j) {
char temp = value[j];
value[j] = value[n - j];
value[n - j] = temp;
}
return this;
}
/**
* Converts to a string representing the data in this string buffer.
* A new <code>String</code> object is allocated and initialized to
* contain the character sequence currently represented by this
* string buffer. This <code>String</code> is then returned. Subsequent
* changes to the string buffer do not affect the contents of the
* <code>String</code>.
* <p>
* Implementation advice: This method can be coded so as to create a new
* <code>String</code> object without allocating new memory to hold a
* copy of the character sequence. Instead, the string can share the
* memory used by the string buffer. Any subsequent operation that alters
* the content or capacity of the string buffer must then make a copy of
* the internal buffer at that time. This strategy is effective for
* reducing the amount of memory allocated by a string concatenation
* operation when it is implemented using a string buffer.
*
* @return a string representation of the string buffer.
*/
public String toString() {
return new String(this);
}
// The following two methods are needed by String to efficiently
// convert a StringBuffer into a String. They are not public.
// They shouldn't be called by anyone but String.
final void setShared() { shared = true; }
final char[] getValue() { return value; }
}
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