## org.apache.lucene.store
Class BufferedIndexInput

    java.lang.Object
      org.apache.lucene.store.DataInput
          org.apache.lucene.store.IndexInput
              org.apache.lucene.store.BufferedIndexInput

All Implemented Interfaces:
  Closeable, Cloneable

Direct Known Subclasses:
  MockIndexInput, SimpleFSDirectory.SimpleFSIndexInput, WindowsDirectory.WindowsIndexInput

    public abstract class BufferedIndexInput

extends IndexInput

Base implementation class for buffered `IndexInput`.

Field Summary
`protected byte[]` `buffer`
`static int` `BUFFER_SIZE` Default buffer size

Constructor Summary
`BufferedIndexInput()` Deprecated. please pass resourceDesc
`BufferedIndexInput(int bufferSize)` Deprecated. please pass resourceDesc
`BufferedIndexInput(String resourceDesc)`
`BufferedIndexInput(String resourceDesc, int bufferSize)` Inits BufferedIndexInput with a specific bufferSize

Method Summary
`Object` `clone()` Returns a clone of this stream.
`void` `copyBytes(IndexOutput out, long numBytes)` Copies `numBytes` bytes to the given `IndexOutput`.
`protected int` `flushBuffer(IndexOutput out, long numBytes)` Flushes the in-memory bufer to the given output, copying at most `numBytes`.
`int` `getBufferSize()` Returns buffer size.
`long` `getFilePointer()` Returns the current position in this file, where the next read will occur.
`protected void` `newBuffer(byte[] newBuffer)`
`byte` `readByte()` Reads and returns a single byte.
`void` `readBytes(byte[] b, int offset, int len)` Reads a specified number of bytes into an array at the specified offset.
`void` `readBytes(byte[] b, int offset, int len, boolean useBuffer)` Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer).
`int` `readInt()` Reads four bytes and returns an int.
`protected abstract void` `readInternal(byte[] b, int offset, int length)` Expert: implements buffer refill.
`long` `readLong()` Reads eight bytes and returns a long.
`short` `readShort()` Reads two bytes and returns a short.
`int` `readVInt()` Reads an int stored in variable-length format.
`long` `readVLong()` Reads a long stored in variable-length format.
`void` `seek(long pos)` Sets current position in this file, where the next read will occur.
`protected abstract void` `seekInternal(long pos)` Expert: implements seek.
`void` `setBufferSize(int newSize)` Change the buffer size used by this IndexInput

Methods inherited from class org.apache.lucene.store.IndexInput
`close, length, skipChars, toString`

Methods inherited from class org.apache.lucene.store.DataInput
`readChars, readString, readStringStringMap, setModifiedUTF8StringsMode`

Methods inherited from class java.lang.Object
`equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### BUFFER_SIZE

    public static final int BUFFER_SIZE

  Default buffer size

  See Also:
    Constant Field Values

### buffer

    protected byte[] buffer

Constructor Detail

### BufferedIndexInput

    @Deprecated
    public BufferedIndexInput()

  Deprecated. please pass resourceDesc

### BufferedIndexInput

    public BufferedIndexInput(String resourceDesc)

### BufferedIndexInput

    @Deprecated
    public BufferedIndexInput(int bufferSize)

  Deprecated. please pass resourceDesc

  Inits BufferedIndexInput with a specific bufferSize

### BufferedIndexInput

    public BufferedIndexInput(String resourceDesc,
                              int bufferSize)

  Inits BufferedIndexInput with a specific bufferSize

Method Detail

### readByte

    public final byte readByte()
                        throws IOException

  Description copied from class: `DataInput`
  Reads and returns a single byte.

  Specified by:
    `readByte` in class `DataInput`
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeByte(byte)`

### setBufferSize

    public final void setBufferSize(int newSize)

  Change the buffer size used by this IndexInput

### newBuffer

    protected void newBuffer(byte[] newBuffer)

### getBufferSize

    public final int getBufferSize()

  Returns buffer size. @see #setBufferSize

### readBytes

    public final void readBytes(byte[] b,
                                int offset,
                                int len)
                         throws IOException

  Description copied from class: `DataInput`
  Reads a specified number of bytes into an array at the specified offset.

  Specified by:
    `readBytes` in class `DataInput`
  Parameters:
    `b` - the array to read bytes into
    `offset` - the offset in the array to start storing bytes
    `len` - the number of bytes to read
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeBytes(byte[],int)`

### readBytes

    public final void readBytes(byte[] b,
                                int offset,
                                int len,
                                boolean useBuffer)
                         throws IOException

  Description copied from class: `DataInput`
  Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer). Currently only `BufferedIndexInput` respects this parameter.

  Overrides:
    `readBytes` in class `DataInput`
  Parameters:
    `b` - the array to read bytes into
    `offset` - the offset in the array to start storing bytes
    `len` - the number of bytes to read
    `useBuffer` - set to false if the caller will handle buffering.
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeBytes(byte[],int)`

### readShort

    public final short readShort()
                          throws IOException

  Description copied from class: `DataInput`
  Reads two bytes and returns a short.

  Overrides:
    `readShort` in class `DataInput`
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeByte(byte)`

### readInt

    public final int readInt()
                      throws IOException

  Description copied from class: `DataInput`
  Reads four bytes and returns an int.

  Overrides:
    `readInt` in class `DataInput`
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeInt(int)`

### readLong

    public final long readLong()
                        throws IOException

  Description copied from class: `DataInput`
  Reads eight bytes and returns a long.

  Overrides:
    `readLong` in class `DataInput`
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeLong(long)`

### readVInt

    public final int readVInt()
                       throws IOException

  Description copied from class: `DataInput`
  Reads an int stored in variable-length format. Reads between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.

  Overrides:
    `readVInt` in class `DataInput`
  Throws:
    `IOException`
  See Also:
    `DataOutput.writeVInt(int)`

### readVLong

    public final long readVLong()
                         throws IOException

  Description copied from class: `DataInput`
  Reads a long stored in variable-length format. Reads between one and nine bytes. Smaller values take fewer bytes. Negative numbers are not supported.

  Overrides:
    `readVLong` in class `DataInput`
  Throws:
    `IOException`

### readInternal

    protected abstract void readInternal(byte[] b,
                                         int offset,
                                         int length)
                                  throws IOException

  Expert: implements buffer refill. Reads bytes from the current position in the input.

  Parameters:
    `b` - the array to read bytes into
    `offset` - the offset in the array to start storing bytes
    `length` - the number of bytes to read
  Throws:
    `IOException`

### getFilePointer

    public final long getFilePointer()

  Description copied from class: `IndexInput`
  Returns the current position in this file, where the next read will occur.

  Specified by:
    `getFilePointer` in class `IndexInput`
  See Also:
    `IndexInput.seek(long)`

### seek

    public final void seek(long pos)
                    throws IOException

  Description copied from class: `IndexInput`
  Sets current position in this file, where the next read will occur.

  Specified by:
    `seek` in class `IndexInput`
  Throws:
    `IOException`
  See Also:
    `IndexInput.getFilePointer()`

### seekInternal

    protected abstract void seekInternal(long pos)
                                  throws IOException

  Expert: implements seek. Sets current position in this file, where the next `readInternal(byte[],int,int)` will occur.

  Throws:
    `IOException`
  See Also:
    `readInternal(byte[],int,int)`

### clone

    public Object clone()

  Description copied from class: `DataInput`
  Returns a clone of this stream.

  Clones of a stream access the same data, and are positioned at the same point as the stream they were cloned from.

  Expert: Subclasses must ensure that clones may be positioned at different points in the input from each other and from the stream they were cloned from.

  Overrides:
    `clone` in class `DataInput`

### flushBuffer

    protected final int flushBuffer(IndexOutput out,
                                    long numBytes)
                             throws IOException

  Flushes the in-memory bufer to the given output, copying at most `numBytes`.

  NOTE: this method does not refill the buffer, however it does advance the buffer position.

  Returns:
    the number of bytes actually flushed from the in-memory buffer.
  Throws:
    `IOException`

### copyBytes

    public void copyBytes(IndexOutput out,
                          long numBytes)
                   throws IOException

  Description copied from class: `IndexInput`
  Copies `numBytes` bytes to the given `IndexOutput`.

  NOTE: this method uses an intermediate buffer to copy the bytes. Consider overriding it in your implementation, if you can make a better, optimized copy.

  NOTE ensure that there are enough bytes in the input to copy to output. Otherwise, different exceptions may be thrown, depending on the implementation.

  Overrides:
    `copyBytes` in class `IndexInput`
  Throws:
    `IOException`