public class

IdentityInputStream

extends InputStream
java.lang.Object
   ↳ java.io.InputStream
     ↳ org.apache.http.impl.io.IdentityInputStream

Class Overview

A stream for reading from a session input buffer.

Summary

Public Constructors
IdentityInputStream(SessionInputBuffer in)
Public Methods
int available()
Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void close()
Closes this stream.
int read(byte[] b, int off, int len)
Reads at most length bytes from this stream and stores them in the byte array b starting at offset.
int read()
Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
[Expand]
Inherited Methods
From class java.io.InputStream
From class java.lang.Object
From interface java.io.Closeable

Public Constructors

public IdentityInputStream (SessionInputBuffer in)

Since: API Level 1

Public Methods

public int available ()

Since: API Level 1

Returns an estimated number of bytes that can be read or skipped without blocking for more input.

Note that this method provides such a weak guarantee that it is not very useful in practice.

Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.

Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".

Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.

It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, length() returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).

The default implementation of this method in InputStream always returns 0. Subclasses should override this method if they are able to indicate the number of bytes available.

Returns
  • the estimated number of bytes available
Throws
IOException

public void close ()

Since: API Level 1

Closes this stream. Concrete implementations of this class should free any resources during close. This implementation does nothing.

Throws
IOException

public int read (byte[] b, int off, int len)

Since: API Level 1

Reads at most length bytes from this stream and stores them in the byte array b starting at offset.

Parameters
b the byte array in which to store the bytes read.
off the initial position in buffer to store the bytes read from this stream.
len the maximum number of bytes to store in b.
Returns
  • the number of bytes actually read or -1 if the end of the stream has been reached.
Throws
IOException

public int read ()

Since: API Level 1

Reads a single byte from this stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of the stream has been reached. Blocks until one byte has been read, the end of the source stream is detected or an exception is thrown.

Returns
  • the byte read or -1 if the end of stream has been reached.
Throws
IOException