org.apache.lucene.store

Class IndexInput

java.lang.Object

org.apache.lucene.store.IndexInput

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

BufferedIndexInput

public abstract class IndexInput
extends Object
implements Cloneable

Abstract base class for input from a file in a Directory. A random-access input stream. Used for all Lucene index input operations.

See Also:

Directory

Constructor Summary

Constructors

Constructor and Description
IndexInput()

Method Summary

Methods

Modifier and Type	Method and Description
Object	clone() Returns a clone of this stream.
abstract void	close() Closes the stream to futher operations.
abstract long	getFilePointer() Returns the current position in this file, where the next read will occur.
abstract long	length() The number of bytes in the file.
abstract byte	readByte() Reads and returns a single byte.
abstract void	readBytes(byte[] b, int offset, int len) Reads a specified number of bytes into an array at the specified offset.
void	readChars(char[] buffer, int start, int length) Reads UTF-8 encoded characters into an array.
int	readInt() Reads four bytes and returns an int.
long	readLong() Reads eight bytes and returns a long.
String	readString() Reads a string.
int	readVInt() Reads an int stored in variable-length format.
long	readVLong() Reads a long stored in variable-length format.
abstract void	seek(long pos) Sets current position in this file, where the next read will occur.

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexInput

public IndexInput()

Method Detail

readByte

public abstract byte readByte()
                       throws IOException

Reads and returns a single byte.

Throws:

IOException

See Also:

IndexOutput.writeByte(byte)

readBytes

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

Reads a specified number of bytes into an array at the specified offset.

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:

IndexOutput.writeBytes(byte[],int)

readInt

public int readInt()
            throws IOException

Reads four bytes and returns an int.

Throws:

IOException

See Also:

IndexOutput.writeInt(int)

readVInt

public int readVInt()
             throws IOException

Reads an int stored in variable-length format. Reads between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Throws:

IOException

See Also:

IndexOutput.writeVInt(int)

readLong

public long readLong()
              throws IOException

Reads eight bytes and returns a long.

Throws:

IOException

See Also:

IndexOutput.writeLong(long)

readVLong

public long readVLong()
               throws IOException

Reads a long stored in variable-length format. Reads between one and nine bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Throws:

IOException

readString

public String readString()
                  throws IOException

Reads a string.

Throws:

IOException

See Also:

IndexOutput.writeString(String)

readChars

public void readChars(char[] buffer,
             int start,
             int length)
               throws IOException

Reads UTF-8 encoded characters into an array.

Parameters:

buffer - the array to read characters into

start - the offset in the array to start storing characters

length - the number of characters to read

Throws:

IOException

See Also:

IndexOutput.writeChars(String,int,int)

close

public abstract void close()
                    throws IOException

Closes the stream to futher operations.

Throws:

IOException

getFilePointer

public abstract long getFilePointer()

Returns the current position in this file, where the next read will occur.

See Also:

seek(long)

seek

public abstract void seek(long pos)
                   throws IOException

Sets current position in this file, where the next read will occur.

Throws:

IOException

See Also:

getFilePointer()

length

public abstract long length()

The number of bytes in the file.

clone

public Object clone()

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 Object