java.io.FilterOutputStream Maven / Gradle / Ivy
/*
* 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 java.util.Arrays;
import libcore.util.SneakyThrow;
/**
* Wraps an existing {@link OutputStream} and performs some transformation on
* the output data while it is being written. Transformations can be anything
* from a simple byte-wise filtering output data to an on-the-fly compression or
* decompression of the underlying stream. Output streams that wrap another
* output stream and provide some additional functionality on top of it usually
* inherit from this class.
*
* @see FilterOutputStream
*/
public class FilterOutputStream extends OutputStream {
/**
* The target output stream for this filter stream.
*/
protected OutputStream out;
/**
* Constructs a new {@code FilterOutputStream} with {@code out} as its
* target stream.
*
* @param out
* the target stream that this stream writes to.
*/
public FilterOutputStream(OutputStream out) {
this.out = out;
}
/**
* Closes this stream. This implementation closes the target stream.
*
* @throws IOException
* if an error occurs attempting to close this stream.
*/
@Override
public void close() throws IOException {
Throwable thrown = null;
try {
flush();
} catch (Throwable e) {
thrown = e;
}
try {
out.close();
} catch (Throwable e) {
if (thrown == null) {
thrown = e;
}
}
if (thrown != null) {
SneakyThrow.sneakyThrow(thrown);
}
}
/**
* Ensures that all pending data is sent out to the target stream. This
* implementation flushes the target stream.
*
* @throws IOException
* if an error occurs attempting to flush this stream.
*/
@Override
public void flush() throws IOException {
out.flush();
}
/**
* Writes {@code count} bytes from the byte array {@code buffer} starting at
* {@code offset} to the target stream.
*
* @param buffer
* the buffer to write.
* @param offset
* the index of the first byte in {@code buffer} to write.
* @param length
* the number of bytes in {@code buffer} to write.
* @throws IndexOutOfBoundsException
* if {@code offset < 0} or {@code count < 0}, or if
* {@code offset + count} is bigger than the length of
* {@code buffer}.
* @throws IOException
* if an I/O error occurs while writing to this stream.
*/
@Override
public void write(byte[] buffer, int offset, int length) throws IOException {
Arrays.checkOffsetAndCount(buffer.length, offset, length);
for (int i = 0; i < length; i++) {
// Call write() instead of out.write() since subclasses could
// override the write() method.
write(buffer[offset + i]);
}
}
/**
* Writes one byte to the target stream. Only the low order byte of the
* integer {@code oneByte} is written.
*
* @param oneByte
* the byte to be written.
* @throws IOException
* if an I/O error occurs while writing to this stream.
*/
@Override
public void write(int oneByte) throws IOException {
out.write(oneByte);
}
}