public abstract class

IndexInput

extends Object
implements Closeable Cloneable
java.lang.Object
   ↳ org.apache.lucene.store.IndexInput
Known Direct Subclasses
Known Indirect Subclasses

Class Overview

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

Summary

Public Constructors
IndexInput()
Public Methods
Object clone()
Returns a clone of this stream.
abstract void close()
Closes the stream to further 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 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).
void readChars(char[] buffer, int start, int length)
This method is deprecated. -- please use readString or readBytes instead, and construct the string from those utf8 bytes
int readInt()
Reads four bytes and returns an int.
long readLong()
Reads eight bytes and returns a long.
String readString()
Reads a string.
Map<String, String> readStringStringMap()
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.
void setModifiedUTF8StringsMode()
Call this if readString should read characters stored in the old modified UTF8 format (length in java chars and java's modified UTF8 encoding).
void skipChars(int length)
This method is deprecated. this method operates on old "modified utf8" encoded strings
[Expand]
Inherited Methods
From class java.lang.Object
From interface java.io.Closeable

Public Constructors

public IndexInput ()

Public Methods

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.

public abstract void close ()

Closes the stream to further operations.

Throws
IOException

public abstract long getFilePointer ()

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

See Also

public abstract long length ()

The number of bytes in the file.

public abstract byte readByte ()

Reads and returns a single byte.

Throws
IOException
See Also

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

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

public 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). Currently only BufferedIndexInput respects this parameter.

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

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

This method is deprecated.
-- please use readString or readBytes instead, and construct the string from those utf8 bytes

Reads Lucene's old "modified 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

public int readInt ()

Reads four bytes and returns an int.

Throws
IOException
See Also

public long readLong ()

Reads eight bytes and returns a long.

Throws
IOException
See Also

public String readString ()

Reads a string.

Throws
IOException
See Also

public Map<String, String> readStringStringMap ()

Throws
IOException

public int readVInt ()

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

public long readVLong ()

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

public abstract void seek (long pos)

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

Throws
IOException
See Also

public void setModifiedUTF8StringsMode ()

Call this if readString should read characters stored in the old modified UTF8 format (length in java chars and java's modified UTF8 encoding). This is used for indices written pre-2.4 See LUCENE-510 for details.

public void skipChars (int length)

This method is deprecated.
this method operates on old "modified utf8" encoded strings

Expert Similar to readChars(char[], int, int) but does not do any conversion operations on the bytes it is reading in. It still has to invoke readByte() just as readChars(char[], int, int) does, but it does not need a buffer to store anything and it does not have to do any of the bitwise operations, since we don't actually care what is in the byte except to determine how many more bytes to read

Parameters
length The number of chars to read
Throws
IOException