197 lines
6.7 KiB
Java
197 lines
6.7 KiB
Java
/*
|
|
* 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;
|
|
|
|
/**
|
|
* FilteredInputStream is a class which takes an input stream and
|
|
* <em>filters</em> the input in some way. The filtered view may be a buffered
|
|
* view or one which uncompresses data before returning bytes read.
|
|
* FilterInputStreams are meant for byte streams.
|
|
*
|
|
* @see FilterOutputStream
|
|
*/
|
|
public class FilterInputStream extends InputStream {
|
|
|
|
/**
|
|
* The target InputStream which is being filtered.
|
|
*/
|
|
protected InputStream in;
|
|
|
|
/**
|
|
* Constructs a new FilterInputStream on the InputStream <code>in</code>.
|
|
* All reads are now filtered through this stream.
|
|
*
|
|
* @param in
|
|
* The non-null InputStream to filter reads on.
|
|
*/
|
|
protected FilterInputStream(InputStream in) {
|
|
super();
|
|
this.in = in;
|
|
}
|
|
|
|
/**
|
|
* Answers a int representing the number of bytes that are available before
|
|
* this FilterInputStream will block. This method returns the number of
|
|
* bytes available in the target stream.
|
|
*
|
|
* @return the number of bytes available before blocking.
|
|
*
|
|
* @throws IOException
|
|
* If an error occurs in this stream.
|
|
*/
|
|
@Override
|
|
public int available() throws IOException {
|
|
return in.available();
|
|
}
|
|
|
|
/**
|
|
* Close this FilterInputStream. This implementation closes the target
|
|
* stream.
|
|
*
|
|
* @throws IOException
|
|
* If an error occurs attempting to close this stream.
|
|
*/
|
|
@Override
|
|
public void close() throws IOException {
|
|
in.close();
|
|
}
|
|
|
|
/**
|
|
* Set a Mark position in this FilterInputStream. The parameter
|
|
* <code>readLimit</code> indicates how many bytes can be read before a
|
|
* mark is invalidated. Sending reset() will reposition the Stream back to
|
|
* the marked position provided <code>readLimit</code> has not been
|
|
* surpassed.
|
|
* <p>
|
|
* This implementation sets a mark in the target stream.
|
|
*
|
|
* @param readlimit
|
|
* the number of bytes to be able to read before invalidating the
|
|
* mark.
|
|
*/
|
|
@Override
|
|
public synchronized void mark(int readlimit) {
|
|
in.mark(readlimit);
|
|
}
|
|
|
|
/**
|
|
* Answers a boolean indicating whether or not this FilterInputStream
|
|
* supports mark() and reset(). This implementation answers whether or not
|
|
* the target stream supports marking.
|
|
*
|
|
* @return <code>true</code> if mark() and reset() are supported,
|
|
* <code>false</code> otherwise.
|
|
*/
|
|
@Override
|
|
public boolean markSupported() {
|
|
return in.markSupported();
|
|
}
|
|
|
|
/**
|
|
* Reads a single byte from this FilterInputStream and returns the result as
|
|
* an int. The low-order byte is returned or -1 of the end of stream was
|
|
* encountered. This implementation returns a byte from the target stream.
|
|
*
|
|
* @return the byte read or -1 if end of stream.
|
|
*
|
|
* @throws IOException
|
|
* If the stream is already closed or another IOException
|
|
* occurs.
|
|
*/
|
|
@Override
|
|
public int read() throws IOException {
|
|
return in.read();
|
|
}
|
|
|
|
/**
|
|
* Reads bytes from this FilterInputStream and stores them in byte array
|
|
* <code>buffer</code>. Answer the number of bytes actually read or -1 if
|
|
* no bytes were read and end of stream was encountered. This implementation
|
|
* reads bytes from the target stream.
|
|
*
|
|
* @param buffer
|
|
* the byte array in which to store the read bytes.
|
|
* @return the number of bytes actually read or -1 if end of stream.
|
|
*
|
|
* @throws IOException
|
|
* If the stream is already closed or another IOException
|
|
* occurs.
|
|
*/
|
|
@Override
|
|
public int read(byte[] buffer) throws IOException {
|
|
return read(buffer, 0, buffer.length);
|
|
}
|
|
|
|
/**
|
|
* Reads at most <code>count</code> bytes from this FilterInputStream and
|
|
* stores them in byte array <code>buffer</code> starting at
|
|
* <code>offset</code>. Answer the number of bytes actually read or -1 if
|
|
* no bytes were read and end of stream was encountered. This implementation
|
|
* reads bytes from the target stream.
|
|
*
|
|
* @param buffer
|
|
* the byte array in which to store the read bytes.
|
|
* @param offset
|
|
* the offset in <code>buffer</code> to store the read bytes.
|
|
* @param count
|
|
* the maximum number of bytes to store in <code>buffer</code>.
|
|
* @return the number of bytes actually read or -1 if end of stream.
|
|
*
|
|
* @throws IOException
|
|
* If the stream is already closed or another IOException
|
|
* occurs.
|
|
*/
|
|
@Override
|
|
public int read(byte[] buffer, int offset, int count) throws IOException {
|
|
return in.read(buffer, offset, count);
|
|
}
|
|
|
|
/**
|
|
* Reset this FilterInputStream to the last marked location. If the
|
|
* <code>readlimit</code> has been passed or no <code>mark</code> has
|
|
* been set, throw IOException. This implementation resets the target
|
|
* stream.
|
|
*
|
|
* @throws IOException
|
|
* If the stream is already closed or another IOException
|
|
* occurs.
|
|
*/
|
|
@Override
|
|
public synchronized void reset() throws IOException {
|
|
in.reset();
|
|
}
|
|
|
|
/**
|
|
* Skips <code>count</code> number of bytes in this InputStream.
|
|
* Subsequent <code>read()</code>'s will not return these bytes unless
|
|
* <code>reset()</code> is used. This implementation skips
|
|
* <code>count</code> number of bytes in the target stream.
|
|
*
|
|
* @param count
|
|
* the number of bytes to skip.
|
|
* @return the number of bytes actually skipped.
|
|
*
|
|
* @throws IOException
|
|
* If the stream is already closed or another IOException
|
|
* occurs.
|
|
*/
|
|
@Override
|
|
public long skip(long count) throws IOException {
|
|
return in.skip(count);
|
|
}
|
|
} |