291 lines
8.9 KiB
Java
291 lines
8.9 KiB
Java
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/*
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* Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.io;
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import java.util.Arrays;
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/**
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* This class implements a character buffer that can be used as an Writer.
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* The buffer automatically grows when data is written to the stream. The data
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* can be retrieved using toCharArray() and toString().
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* <P>
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* Note: Invoking close() on this class has no effect, and methods
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* of this class can be called after the stream has closed
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* without generating an IOException.
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*
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* @author Herb Jellinek
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* @since 1.1
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*/
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public
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class CharArrayWriter extends Writer {
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/**
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* The buffer where data is stored.
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*/
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protected char buf[];
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/**
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* The number of chars in the buffer.
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*/
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protected int count;
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/**
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* Creates a new CharArrayWriter.
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*/
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public CharArrayWriter() {
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this(32);
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}
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/**
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* Creates a new CharArrayWriter with the specified initial size.
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*
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* @param initialSize an int specifying the initial buffer size.
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* @exception IllegalArgumentException if initialSize is negative
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*/
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public CharArrayWriter(int initialSize) {
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if (initialSize < 0) {
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throw new IllegalArgumentException("Negative initial size: "
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+ initialSize);
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}
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buf = new char[initialSize];
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}
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/**
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* Writes a character to the buffer.
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*/
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public void write(int c) {
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synchronized (lock) {
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int newcount = count + 1;
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if (newcount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
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}
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buf[count] = (char)c;
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count = newcount;
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}
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}
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/**
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* Writes characters to the buffer.
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* @param c the data to be written
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* @param off the start offset in the data
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* @param len the number of chars that are written
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*
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* @throws IndexOutOfBoundsException
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* If {@code off} is negative, or {@code len} is negative,
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* or {@code off + len} is negative or greater than the length
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* of the given array
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*/
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public void write(char c[], int off, int len) {
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if ((off < 0) || (off > c.length) || (len < 0) ||
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((off + len) > c.length) || ((off + len) < 0)) {
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throw new IndexOutOfBoundsException();
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} else if (len == 0) {
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return;
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}
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synchronized (lock) {
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int newcount = count + len;
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if (newcount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
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}
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System.arraycopy(c, off, buf, count, len);
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count = newcount;
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}
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}
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/**
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* Write a portion of a string to the buffer.
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* @param str String to be written from
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* @param off Offset from which to start reading characters
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* @param len Number of characters to be written
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*
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* @throws IndexOutOfBoundsException
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* If {@code off} is negative, or {@code len} is negative,
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* or {@code off + len} is negative or greater than the length
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* of the given string
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*/
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public void write(String str, int off, int len) {
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synchronized (lock) {
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int newcount = count + len;
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if (newcount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
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}
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str.getChars(off, off + len, buf, count);
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count = newcount;
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}
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}
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/**
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* Writes the contents of the buffer to another character stream.
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*
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* @param out the output stream to write to
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* @throws IOException If an I/O error occurs.
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*/
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public void writeTo(Writer out) throws IOException {
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synchronized (lock) {
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out.write(buf, 0, count);
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}
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}
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/**
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* Appends the specified character sequence to this writer.
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*
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* <p> An invocation of this method of the form {@code out.append(csq)}
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* behaves in exactly the same way as the invocation
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*
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* <pre>
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* out.write(csq.toString()) </pre>
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*
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* <p> Depending on the specification of {@code toString} for the
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* character sequence {@code csq}, the entire sequence may not be
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* appended. For instance, invoking the {@code toString} method of a
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* character buffer will return a subsequence whose content depends upon
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* the buffer's position and limit.
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*
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* @param csq
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* The character sequence to append. If {@code csq} is
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* {@code null}, then the four characters {@code "null"} are
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* appended to this writer.
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*
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* @return This writer
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*
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* @since 1.5
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*/
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public CharArrayWriter append(CharSequence csq) {
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String s = String.valueOf(csq);
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write(s, 0, s.length());
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return this;
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}
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/**
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* Appends a subsequence of the specified character sequence to this writer.
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*
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* <p> An invocation of this method of the form
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* {@code out.append(csq, start, end)} when
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* {@code csq} is not {@code null}, behaves in
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* exactly the same way as the invocation
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*
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* <pre>
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* out.write(csq.subSequence(start, end).toString()) </pre>
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*
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* @param csq
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* The character sequence from which a subsequence will be
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* appended. If {@code csq} is {@code null}, then characters
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* will be appended as if {@code csq} contained the four
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* characters {@code "null"}.
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*
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* @param start
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* The index of the first character in the subsequence
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*
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* @param end
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* The index of the character following the last character in the
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* subsequence
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*
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* @return This writer
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*
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* @throws IndexOutOfBoundsException
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* If {@code start} or {@code end} are negative, {@code start}
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* is greater than {@code end}, or {@code end} is greater than
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* {@code csq.length()}
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*
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* @since 1.5
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*/
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public CharArrayWriter append(CharSequence csq, int start, int end) {
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if (csq == null) csq = "null";
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return append(csq.subSequence(start, end));
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}
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/**
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* Appends the specified character to this writer.
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*
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* <p> An invocation of this method of the form {@code out.append(c)}
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* behaves in exactly the same way as the invocation
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*
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* <pre>
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* out.write(c) </pre>
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*
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* @param c
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* The 16-bit character to append
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*
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* @return This writer
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*
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* @since 1.5
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*/
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public CharArrayWriter append(char c) {
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write(c);
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return this;
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}
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/**
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* Resets the buffer so that you can use it again without
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* throwing away the already allocated buffer.
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*/
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public void reset() {
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count = 0;
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}
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/**
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* Returns a copy of the input data.
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*
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* @return an array of chars copied from the input data.
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*/
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public char[] toCharArray() {
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synchronized (lock) {
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return Arrays.copyOf(buf, count);
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}
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}
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/**
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* Returns the current size of the buffer.
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*
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* @return an int representing the current size of the buffer.
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*/
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public int size() {
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return count;
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}
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/**
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* Converts input data to a string.
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* @return the string.
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*/
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public String toString() {
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synchronized (lock) {
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return new String(buf, 0, count);
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}
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}
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/**
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* Flush the stream.
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*/
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public void flush() { }
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/**
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* Close the stream. This method does not release the buffer, since its
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* contents might still be required. Note: Invoking this method in this class
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* will have no effect.
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*/
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public void close() { }
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}
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