/*
* @(#)CharArrayWriter.java 1.23 04/07/16
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.io;
/**
* This class implements a character buffer that can be used as an Writer.
* The buffer automatically grows when data is written to the stream. The data
* can be retrieved using toCharArray() and toString().
* <P>
* Note: Invoking close() on this class has no effect, and methods
* of this class can be called after the stream has closed
* without generating an IOException.
*
* @author Herb Jellinek
* @version 1.23, 07/16/04
* @since JDK1.1
*/
public
class CharArrayWriter extends Writer {
/**
* The buffer where data is stored.
*/
protected char buf[];
/**
* The number of chars in the buffer.
*/
protected int count;
/**
* Creates a new CharArrayWriter.
*/
public CharArrayWriter() {
this(32);
}
/**
* Creates a new CharArrayWriter with the specified initial size.
*
* @param initialSize an int specifying the initial buffer size.
* @exception IllegalArgumentException if initialSize is negative
*/
public CharArrayWriter(int initialSize) {
if (initialSize < 0) {
throw new IllegalArgumentException("Negative initial size: "
+ initialSize);
}
buf = new char[initialSize];
}
/**
* Writes a character to the buffer.
*/
public void write(int c) {
synchronized (lock) {
int newcount = count + 1;
if (newcount > buf.length) {
char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
System.arraycopy(buf, 0, newbuf, 0, count);
buf = newbuf;
}
buf[count] = (char)c;
count = newcount;
}
}
/**
* Writes characters to the buffer.
* @param c the data to be written
* @param off the start offset in the data
* @param len the number of chars that are written
*/
public void write(char c[], int off, int len) {
if ((off < 0) || (off > c.length) || (len < 0) ||
((off + len) > c.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
synchronized (lock) {
int newcount = count + len;
if (newcount > buf.length) {
char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
System.arraycopy(buf, 0, newbuf, 0, count);
buf = newbuf;
}
System.arraycopy(c, off, buf, count, len);
count = newcount;
}
}
/**
* Write a portion of a string to the buffer.
* @param str String to be written from
* @param off Offset from which to start reading characters
* @param len Number of characters to be written
*/
public void write(String str, int off, int len) {
synchronized (lock) {
int newcount = count + len;
if (newcount > buf.length) {
char newbuf[] = new char[Math.max(buf.length << 1, newcount)];
System.arraycopy(buf, 0, newbuf, 0, count);
buf = newbuf;
}
str.getChars(off, off + len, buf, count);
count = newcount;
}
}
/**
* Writes the contents of the buffer to another character stream.
*
* @param out the output stream to write to
* @throws IOException If an I/O error occurs.
*/
public void writeTo(Writer out) throws IOException {
synchronized (lock) {
out.write(buf, 0, count);
}
}
/**
* Appends the specified character sequence to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(csq)</tt>
* behaves in exactly the same way as the invocation
*
* <pre>
* out.write(csq.toString()) </pre>
*
* <p> Depending on the specification of <tt>toString</tt> for the
* character sequence <tt>csq</tt>, the entire sequence may not be
* appended. For instance, invoking the <tt>toString</tt> method of a
* character buffer will return a subsequence whose content depends upon
* the buffer's position and limit.
*
* @param csq
* The character sequence to append. If <tt>csq</tt> is
* <tt>null</tt>, then the four characters <tt>"null"</tt> are
* appended to this writer.
*
* @return This writer
*
* @since 1.5
*/
public CharArrayWriter append(CharSequence csq) {
String s = (csq == null ? "null" : csq.toString());
write(s, 0, s.length());
return this;
}
/**
* Appends a subsequence of the specified character sequence to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(csq, start,
* end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
* exactly the same way as the invocation
*
* <pre>
* out.write(csq.subSequence(start, end).toString()) </pre>
*
* @param csq
* The character sequence from which a subsequence will be
* appended. If <tt>csq</tt> is <tt>null</tt>, then characters
* will be appended as if <tt>csq</tt> contained the four
* characters <tt>"null"</tt>.
*
* @param start
* The index of the first character in the subsequence
*
* @param end
* The index of the character following the last character in the
* subsequence
*
* @return This writer
*
* @throws IndexOutOfBoundsException
* If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
* is greater than <tt>end</tt>, or <tt>end</tt> is greater than
* <tt>csq.length()</tt>
*
* @since 1.5
*/
public CharArrayWriter append(CharSequence csq, int start, int end) {
String s = (csq == null ? "null" : csq).subSequence(start, end).toString();
write(s, 0, s.length());
return this;
}
/**
* Appends the specified character to this writer.
*
* <p> An invocation of this method of the form <tt>out.append(c)</tt>
* behaves in exactly the same way as the invocation
*
* <pre>
* out.write(c) </pre>
*
* @param c
* The 16-bit character to append
*
* @return This writer
*
* @since 1.5
*/
public CharArrayWriter append(char c) {
write(c);
return this;
}
/**
* Resets the buffer so that you can use it again without
* throwing away the already allocated buffer.
*/
public void reset() {
count = 0;
}
/**
* Returns a copy of the input data.
*
* @return an array of chars copied from the input data.
*/
public char toCharArray()[] {
synchronized (lock) {
char newbuf[] = new char[count];
System.arraycopy(buf, 0, newbuf, 0, count);
return newbuf;
}
}
/**
* Returns the current size of the buffer.
*
* @return an int representing the current size of the buffer.
*/
public int size() {
return count;
}
/**
* Converts input data to a string.
* @return the string.
*/
public String toString() {
synchronized (lock) {
return new String(buf, 0, count);
}
}
/**
* Flush the stream.
*/
public void flush() { }
/**
* Close the stream. This method does not release the buffer, since its
* contents might still be required. Note: Invoking this method in this class
* will have no effect.
*/
public void close() { }
}
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