Package java.io

Class BufferedInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
java.io.BufferedInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
public class BufferedInputStream
extends FilterInputStream
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:
BufferedOutputStream

  • Field Summary

    Fields
    Modifier and Type Field Description
    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.

    Fields inherited from class java.io.FilterInputStream

    in

  • Constructor Summary

    Constructors
    Constructor Description
    BufferedInputStream​(InputStream in)
    Constructs a new BufferedInputStream, providing in with a buffer of 8192 bytes.
    BufferedInputStream​(InputStream in, int size)
    Constructs a new BufferedInputStream, providing in with size bytes of buffer.

  • Method Summary

    Modifier and Type Method Description
    int available()
    Returns an estimated number of bytes that can be read or skipped without blocking for more input.
    void close()
    Closes this stream.
    void mark​(int readlimit)
    Sets a mark position in this stream.
    boolean markSupported()
    Indicates whether BufferedInputStream supports the mark() and reset() methods.
    int read()
    Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
    int read​(byte[] buffer, int byteOffset, int byteCount)
    Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset.
    void reset()
    Resets this stream to the last marked location.
    long skip​(long byteCount)
    Skips byteCount bytes in this stream.

    Methods inherited from class java.io.InputStream

    read

    Methods inherited from class java.lang.Object

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

  • Field Details

    • buf

      protected volatile byte[] buf
      The buffer containing the current bytes read from the target InputStream.

    • count

      protected int count
      The total number of bytes inside the byte array buf.

    • marklimit

      protected int marklimit
      The current limit, which when passed, invalidates the current mark.

    • markpos

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

    • pos

      protected int pos
      The current position within the byte array buf.

  • Constructor Details

    • BufferedInputStream

      public BufferedInputStream​(InputStream in)
      Constructs a new BufferedInputStream, providing in with a buffer of 8192 bytes.

      Warning: passing a null source creates a closed BufferedInputStream. All read operations on such a stream will fail with an IOException.

      Parameters:
      in - the InputStream the buffer reads from.

    • BufferedInputStream

      public BufferedInputStream​(InputStream in, int size)
      Constructs a new BufferedInputStream, providing in with size bytes of buffer.

      Warning: passing a null source creates a closed BufferedInputStream. All read operations on such a stream will fail with an IOException.

      Parameters:
      in - the InputStream the buffer reads from.
      size - the size of buffer in bytes.
      Throws:
      IllegalArgumentException - if size <= 0.

  • Method Details

    • available

      public int available() throws IOException
      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 InputStream.available() for important caveats.
      Overrides:
      available in class FilterInputStream
      Returns:
      the estimated number of bytes available
      Throws:
      IOException - if this stream is closed or an error occurs

    • close

      public void close() throws IOException
      Closes this stream. The source stream is closed and any resources associated with it are released.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class FilterInputStream
      Throws:
      IOException - if an error occurs while closing this stream.

    • mark

      public void mark​(int readlimit)
      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.
      Overrides:
      mark in class FilterInputStream
      Parameters:
      readlimit - the number of bytes that can be read before the mark is invalidated.
      See Also:
      reset()

    • markSupported

      public boolean markSupported()
      Indicates whether BufferedInputStream supports the mark() and reset() methods.
      Overrides:
      markSupported in class FilterInputStream
      Returns:
      true for BufferedInputStreams.
      See Also:
      mark(int), reset()

    • read

      public int read() throws IOException
      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.
      Overrides:
      read in class FilterInputStream
      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.

    • read

      public int read​(byte[] buffer, int byteOffset, int byteCount) throws IOException
      Description copied from class: InputStream
      Reads up to byteCount bytes from this stream and stores them in the byte array buffer starting at byteOffset. Returns the number of bytes actually read or -1 if the end of the stream has been reached.
      Overrides:
      read in class FilterInputStream
      Throws:
      IOException - if the stream is closed or another IOException occurs.

    • reset

      public void reset() throws IOException
      Resets this stream to the last marked location.
      Overrides:
      reset in class FilterInputStream
      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:
      mark(int)

    • skip

      public long skip​(long byteCount) throws IOException
      Skips byteCount bytes in this stream. Subsequent calls to read will not return these bytes unless reset is used.
      Overrides:
      skip in class FilterInputStream
      Parameters:
      byteCount - the number of bytes to skip. skip does nothing and returns 0 if byteCount is less than zero.
      Returns:
      the number of bytes actually skipped.
      Throws:
      IOException - if this stream is closed or another IOException occurs.
      See Also:
      FilterInputStream.mark(int), FilterInputStream.reset()