ContentLengthInputStream

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org.apache.http.io
Class ContentLengthInputStream

java.lang.Object
  java.io.InputStream
      org.apache.http.io.ContentLengthInputStream

All Implemented Interfaces:: java.io.Closeable

public class ContentLengthInputStream
extends java.io.InputStream

This class cuts the wrapped InputStream off after a specified number of bytes.

Note that this class NEVER closes the underlying stream, even when close gets called. Instead, it will read until the "end" of its chunking on close, which allows for the seamless invocation of subsequent HTTP 1.1 calls, while not requiring the client to remember to read the entire contents of the response.

Implementation note: Choices abound. One approach would pass through the InputStream.mark(int)>InputStream.mark(int) 55 and InputStream.reset()>InputStream.reset() 55 calls to the underlying stream. That's tricky, though, because you then have to start duplicating the work of keeping track of how much a reset rewinds. Further, you have to watch out for the "readLimit", and since the semantics for the readLimit leave room for differing implementations, you might get into a lot of trouble.

Alternatively, you could make this class extend java.io.BufferedInputStream and then use the protected members of that class to avoid duplicated effort. That solution has the side effect of adding yet another possible layer of buffering.

Then, there is the simple choice, which this takes - simply don't support InputStream.mark(int)>InputStream.mark(int) 55 and InputStream.reset()>InputStream.reset() 55 . That choice has the added benefit of keeping this class very simple.

Since:: 2.0

Field Summary

private static int BUFFER_SIZE


private boolean closed
          True if the stream is closed.

private long contentLength
          The maximum number of bytes that can be read from the stream.

private HttpDataReceiver in
          Wrapped input stream that all calls are delegated to.

private long pos
          The current position

Constructor Summary

ContentLengthInputStream(HttpDataReceiver in, long contentLength)
          Creates a new length limited stream

Method Summary

void close()
          Reads until the end of the known length of content.

int read()
          Read the next byte from the stream

int read(byte[] b)
          Read more bytes from the stream.

int read(byte[] b, int off, int len)
          Does standard InputStream.read(byte[], int, int)>InputStream.read(byte[], int, int) 55 behavior, but also notifies the watcher when the contents have been consumed.

long skip(long n)
          Skips and discards a number of bytes from the input stream.

Methods inherited from class java.io.InputStream

available, mark, markSupported, reset

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

BUFFER_SIZE

private static int BUFFER_SIZE

contentLength

private long contentLength

The maximum number of bytes that can be read from the stream. Subsequent read operations will return -1.

pos

private long pos

The current position

closed

private boolean closed

True if the stream is closed.

in

private HttpDataReceiver in

Wrapped input stream that all calls are delegated to.

Constructor Detail