public class

BufferedInputStream

extends FilterInputStream
java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ java.io.BufferedInputStream

Class Overview

Wraps an existing InputStream and buffers the input. Expensive interaction with the underlying input stream is minimized, since most (smaller) requests can be satisfied by accessing the buffer alone. The drawback is that some extra space is required to hold the buffer and that copying takes place when filling that buffer, but this is usually outweighed by the performance benefits.

A typical application pattern for the class looks like this:

 BufferedInputStream buf = new BufferedInputStream(new FileInputStream("file.java"));

See Also

Summary

Fields
protected byte[] buf The buffer containing the current bytes read from the target InputStream.
protected int count The total number of bytes inside the byte array buf.
protected int marklimit The current limit, which when passed, invalidates the current mark.
protected int markpos The currently marked position.
protected int pos The current position within the byte array buf.
[Expand]
Inherited Fields
From class java.io.FilterInputStream
Public Constructors
BufferedInputStream(InputStream in)
Constructs a new BufferedInputStream on the InputStream in.
BufferedInputStream(InputStream in, int size)
Constructs a new BufferedInputStream on the InputStream in.
Public Methods
synchronized int available()
Returns an estimated number of bytes that can be read or skipped without blocking for more input.
void close()
Closes this stream.
synchronized void mark(int readlimit)
Sets a mark position in this stream.
boolean markSupported()
Indicates whether BufferedInputStream supports the mark() and reset() methods.
synchronized int read(byte[] buffer, int offset, int length)
Reads at most length bytes from this stream and stores them in byte array buffer starting at offset offset.
synchronized int read()
Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
synchronized void reset()
Resets this stream to the last marked location.
synchronized long skip(long amount)
Skips amount number of bytes in this stream.
[Expand]
Inherited Methods
From class java.io.FilterInputStream
From class java.io.InputStream
From class java.lang.Object
From interface java.io.Closeable

Fields

protected byte[] buf

Since: API Level 1

The buffer containing the current bytes read from the target InputStream.

protected int count

Since: API Level 1

The total number of bytes inside the byte array buf.

protected int marklimit

Since: API Level 1

The current limit, which when passed, invalidates the current mark.

protected int markpos

Since: API Level 1

The currently marked position. -1 indicates no mark has been set or the mark has been invalidated.

protected int pos

Since: API Level 1

The current position within the byte array buf.

Public Constructors

public BufferedInputStream (InputStream in)

Since: API Level 1

Constructs a new BufferedInputStream on the InputStream in. The default buffer size (8 KB) is allocated and all reads can now be filtered through this stream.

Parameters
in the InputStream the buffer reads from.

public BufferedInputStream (InputStream in, int size)

Since: API Level 1

Constructs a new BufferedInputStream on the InputStream in. The buffer size is specified by the parameter size and all reads are now filtered through this stream.

Parameters
in the input stream the buffer reads from.
size the size of buffer to allocate.
Throws
IllegalArgumentException if size < 0.

Public Methods

public synchronized int available ()

Since: API Level 1

Returns an estimated number of bytes that can be read or skipped without blocking for more input. This method returns the number of bytes available in the buffer plus those available in the source stream, but see available() for important caveats.

Returns
  • the estimated number of bytes available
Throws
IOException if this stream is closed or an error occurs

public void close ()

Since: API Level 1

Closes this stream. The source stream is closed and any resources associated with it are released.

Throws
IOException if an error occurs while closing this stream.

public synchronized void mark (int readlimit)

Since: API Level 1

Sets a mark position in this stream. The parameter readlimit indicates how many bytes can be read before a mark is invalidated. Calling reset() will reposition the stream back to the marked position if readlimit has not been surpassed. The underlying buffer may be increased in size to allow readlimit number of bytes to be supported.

Parameters
readlimit the number of bytes that can be read before the mark is invalidated.
See Also

public boolean markSupported ()

Since: API Level 1

Indicates whether BufferedInputStream supports the mark() and reset() methods.

Returns
  • true for BufferedInputStreams.
See Also

public synchronized int read (byte[] buffer, int offset, int length)

Since: API Level 1

Reads at most length bytes from this stream and stores them in byte array buffer starting at offset offset. Returns the number of bytes actually read or -1 if no bytes were read and the end of the stream was encountered. If all the buffered bytes have been used, a mark has not been set and the requested number of bytes is larger than the receiver's buffer size, this implementation bypasses the buffer and simply places the results directly into buffer.

Parameters
buffer the byte array in which to store the bytes read.
offset the initial position in buffer to store the bytes read from this stream.
length the maximum number of bytes to store in buffer.
Returns
  • the number of bytes actually read or -1 if end of stream.
Throws
IndexOutOfBoundsException if offset < 0 or length < 0, or if offset + length is greater than the size of buffer.
IOException if the stream is already closed or another IOException occurs.

public synchronized 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 source string has been reached. If the internal buffer does not contain any available bytes then it is filled from the source stream and the first byte is returned.

Returns
  • the byte read or -1 if the end of the source stream has been reached.
Throws
IOException if this stream is closed or another IOException occurs.

public synchronized void reset ()

Since: API Level 1

Resets this stream to the last marked location.

Throws
IOException if this stream is closed, no mark has been set or the mark is no longer valid because more than readlimit bytes have been read since setting the mark.
See Also

public synchronized long skip (long amount)

Since: API Level 1

Skips amount number of bytes in this stream. Subsequent read()'s will not return these bytes unless reset() is used.

Parameters
amount the number of bytes to skip. skip does nothing and returns 0 if amount is less than zero.
Returns
  • the number of bytes actually skipped.
Throws
IOException if this stream is closed or another IOException occurs.