/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.io;
import org.apache.harmony.luni.util.Msg;
/**
* Places information on a communications pipe. When two threads want to pass
* data back and forth, one creates a piped writer and the other creates a piped
* reader.
*
* @see PipedReader
*
* @since Android 1.0
*/
public class PipedWriter extends Writer {
/**
* The destination PipedReader
*/
private PipedReader dest;
private boolean closed;
/**
* Constructs a new unconnected {@code PipedWriter}. The resulting writer
* must be connected to a {@code PipedReader} before data may be written to
* it.
*
* @see PipedReader
* @since Android 1.0
*/
public PipedWriter() {
super();
}
/**
* Constructs a new {@code PipedWriter} connected to the {@link PipedReader}
* {@code dest}. Any data written to this writer can be read from {@code
* dest}.
*
* @param dest
* the {@code PipedReader} to connect to.
* @throws IOException
* if {@code dest} is already connected.
* @since Android 1.0
*/
public PipedWriter(PipedReader dest) throws IOException {
super(dest);
connect(dest);
}
/**
* Closes this writer. If a {@link PipedReader} is connected to this writer,
* it is closed as well and the pipe is disconnected. Any data buffered in
* the reader can still be read.
*
* @throws IOException
* if an error occurs while closing this writer.
* @since Android 1.0
*/
@Override
public void close() throws IOException {
synchronized (lock) {
/* Is the pipe connected? */
if (dest != null) {
dest.done();
dest = null;
}
closed = true;
}
}
/**
* Connects this {@code PipedWriter} to a {@link PipedReader}. Any data
* written to this writer becomes readable in the reader.
*
* @param stream
* the reader to connect to.
* @throws IOException
* if this writer is closed or already connected, or if {@code
* stream} is already connected.
* @since Android 1.0
*/
public void connect(PipedReader stream) throws IOException {
synchronized (lock) {
if (this.dest != null) {
throw new IOException(Msg.getString("K0079")); //$NON-NLS-1$
}
if (closed) {
throw new IOException(Msg.getString("K0078")); //$NON-NLS-1$
}
stream.establishConnection();
this.dest = stream;
}
}
/**
* Notifies the readers of this {@code PipedReader} that characters can be read. This
* method does nothing if this Writer is not connected.
*
* @throws IOException
* if an I/O error occurs while flushing this writer.
* @since Android 1.0
*/
@Override
public void flush() throws IOException {
if (dest != null) {
dest.flush();
}
}
/**
* Writes {@code count} characters from the character array {@code buffer}
* starting at offset {@code index} to this writer. The written data can
* then be read from the connected {@link PipedReader} instance.
* <p>
* Separate threads should be used to write to a {@code PipedWriter} and to
* read from the connected {@code PipedReader}. If the same thread is used,
* a deadlock may occur.
* </p>
*
* @param buffer
* the buffer to write.
* @param offset
* the index of the first character in {@code buffer} to write.
* @param count
* the number of characters from {@code buffer} to write to this
* writer.
* @throws IndexOutOfBoundsException
* if {@code offset < 0} or {@code count < 0}, or if {@code
* offset + count} is bigger than the length of {@code buffer}.
* @throws InterruptedIOException
* if the pipe is full and the current thread is interrupted
* waiting for space to write data. This case is not currently
* handled correctly.
* @throws IOException
* if this writer is closed or not connected, if the target
* reader is closed or if the thread reading from the target
* reader is no longer alive. This case is currently not handled
* correctly.
* @throws NullPointerException
* if {@code buffer} is {@code null}.
* @since Android 1.0
*/
@Override
public void write(char[] buffer, int offset, int count) throws IOException {
// BEGIN android-note
// changed array notation to be consistent with the rest of harmony
// END android-note
synchronized (lock) {
if (closed) {
throw new IOException(Msg.getString("K0078")); //$NON-NLS-1$
}
if (dest == null) {
throw new IOException(Msg.getString("K007b")); //$NON-NLS-1$
}
if (buffer == null) {
throw new NullPointerException(Msg.getString("K0047")); //$NON-NLS-1$
}
// avoid int overflow
// BEGIN android-changed
// Exception priorities (in case of multiple errors) differ from
// RI, but are spec-compliant.
// removed redundant check, used (offset | count) < 0
// instead of (offset < 0) || (count < 0) to safe one operation
if ((offset | count) < 0 || count > buffer.length - offset) {
throw new IndexOutOfBoundsException(Msg.getString("K002f")); //$NON-NLS-1$
}
// END android-changed
dest.receive(buffer, offset, count);
}
}
/**
* Writes a single character {@code c} to this writer. This character can
* then be read from the connected {@link PipedReader} instance.
* <p>
* Separate threads should be used to write to a {@code PipedWriter} and to
* read from the connected {@code PipedReader}. If the same thread is used,
* a deadlock may occur.
* </p>
*
* @param c
* the character to write.
* @throws InterruptedIOException
* if the pipe is full and the current thread is interrupted
* waiting for space to write data. This case is not currently
* handled correctly.
* @throws IOException
* if this writer is closed or not connected, if the target
* reader is closed or if the thread reading from the target
* reader is no longer alive. This case is currently not handled
* correctly.
* @since Android 1.0
*/
@Override
public void write(int c) throws IOException {
synchronized (lock) {
if (closed) {
throw new IOException(Msg.getString("K0078")); //$NON-NLS-1$
}
if (dest == null) {
throw new IOException(Msg.getString("K007b")); //$NON-NLS-1$
}
dest.receive((char) c);
}
}
}
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