| /* |
| * 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 org.apache.commons.vfs2.util; |
| |
| import java.io.BufferedOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| import org.apache.commons.vfs2.FileSystemException; |
| |
| /** |
| * An OutputStream that provides buffering and end-of-stream monitoring. |
| */ |
| public class MonitorOutputStream |
| extends BufferedOutputStream |
| { |
| private final AtomicBoolean finished = new AtomicBoolean(false); |
| |
| public MonitorOutputStream(final OutputStream out) |
| { |
| super(out); |
| } |
| |
| /** |
| * Closes this output stream. |
| * <p> |
| * This makes sure the buffers are flushed, close the output |
| * stream and it will call {@link #onClose()} |
| * and re-throw last exception from any of the three. |
| * <p> |
| * This does nothing if the stream is closed already. |
| * |
| * @throws IOException if an error occurs. |
| */ |
| @Override |
| public void close() throws IOException |
| { |
| // do not use super.close() |
| // on Java 8 it might throw self suppression, see JDK-8042377 |
| // in older Java it silently ignores flush() errors |
| if (finished.getAndSet(true)) |
| { |
| return; |
| } |
| |
| IOException exc = null; |
| |
| // flush the buffer and out stream |
| try |
| { |
| super.flush(); |
| } |
| catch (final IOException ioe) |
| { |
| exc = ioe; |
| } |
| |
| // close the out stream without using super.close() |
| try |
| { |
| super.out.close(); |
| } |
| catch (final IOException ioe) |
| { |
| exc = ioe; |
| } |
| |
| // Notify of end of output |
| try |
| { |
| onClose(); |
| } |
| catch (final IOException ioe) |
| { |
| exc = ioe; |
| } |
| |
| if (exc != null) |
| { |
| throw exc; |
| } |
| } |
| |
| |
| /** |
| * @param b The character to write. |
| * @throws IOException if an error occurs. |
| * @since 2.0 |
| */ |
| @Override |
| public synchronized void write(final int b) throws IOException |
| { |
| assertOpen(); |
| super.write(b); |
| } |
| |
| /** |
| * @param b The byte array. |
| * @param off The offset into the array. |
| * @param len The number of bytes to write. |
| * @throws IOException if an error occurs. |
| * @since 2.0 |
| */ |
| @Override |
| public synchronized void write(final byte[] b, final int off, final int len) throws IOException |
| { |
| assertOpen(); |
| super.write(b, off, len); |
| } |
| |
| /** |
| * @throws IOException if an error occurs. |
| * @since 2.0 |
| */ |
| @Override |
| public synchronized void flush() throws IOException |
| { |
| assertOpen(); |
| super.flush(); |
| } |
| |
| /** |
| * @param b The byte array. |
| * @throws IOException if an error occurs. |
| * @since 2.0 |
| */ |
| @Override |
| public void write(final byte[] b) throws IOException |
| { |
| assertOpen(); |
| super.write(b); |
| } |
| |
| /** |
| * Check if file is still open. |
| * <p> |
| * This is a workaround for an oddity with Java's BufferedOutputStream where you can write to |
| * even if the stream has been closed. |
| * |
| * @throws FileSystemException if already closed. |
| * @since 2.0 |
| */ |
| protected void assertOpen() throws FileSystemException |
| { |
| if (finished.get()) |
| { |
| throw new FileSystemException("vfs.provider/closed.error"); |
| } |
| } |
| |
| /** |
| * Called after this stream is closed. |
| * <p> |
| * This implementation does nothing. |
| * |
| * @throws IOException if an error occurs. |
| */ |
| // IOException is needed because subclasses may need to throw it |
| protected void onClose() throws IOException |
| { |
| } |
| } |