IndexInput (Lucene 2.9.4 API)

java.lang.Object
- org.apache.lucene.store.IndexInput

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

BufferedIndexInput, ChecksumIndexInput, DbIndexInput, JEIndexInput
```
public abstract class IndexInput
extends java.lang.Object
implements java.lang.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()

Constructors
Constructor and Description
`IndexInput()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`java.lang.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)` 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.
`java.lang.String`	`readString()` Reads a string.
`java.util.Map`	`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)` Deprecated. this method operates on old "modified utf8" encoded strings

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 java.io.IOException
```
    Reads and returns a single byte.
    
    Throws:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeByte(byte)
  - readBytes
```
public abstract void readBytes(byte[] b,
                               int offset,
                               int len)
                        throws java.io.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:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeBytes(byte[],int)
  - readBytes
```
public void readBytes(byte[] b,
                      int offset,
                      int len,
                      boolean useBuffer)
               throws java.io.IOException
```
    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:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeBytes(byte[],int)
  - readInt
```
public int readInt()
            throws java.io.IOException
```
    Reads four bytes and returns an int.
    
    Throws:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeInt(int)
  - readVInt
```
public int readVInt()
             throws java.io.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:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeVInt(int)
  - readLong
```
public long readLong()
              throws java.io.IOException
```
    Reads eight bytes and returns a long.
    
    Throws:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeLong(long)
  - readVLong
```
public long readVLong()
               throws java.io.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:
    
    java.io.IOException
  - setModifiedUTF8StringsMode
```
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.
  - readString
```
public java.lang.String readString()
                            throws java.io.IOException
```
    Reads a string.
    
    Throws:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeString(String)
  - readChars
```
public void readChars(char[] buffer,
                      int start,
                      int length)
               throws java.io.IOException
```
    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:
    
    java.io.IOException
    
    See Also:
    
    IndexOutput.writeChars(String,int,int)
  - skipChars
```
public void skipChars(int length)
               throws java.io.IOException
```
    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:
    
    java.io.IOException
  - close
```
public abstract void close()
                    throws java.io.IOException
```
    Closes the stream to further operations.
    
    Throws:
    
    java.io.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 java.io.IOException
```
    Sets current position in this file, where the next read will occur.
    
    Throws:
    
    java.io.IOException
    
    See Also:
    
    getFilePointer()
  - length
```
public abstract long length()
```
    The number of bytes in the file.
  - clone
```
public java.lang.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 java.lang.Object
  - readStringStringMap
```
public java.util.Map readStringStringMap()
                                  throws java.io.IOException
```
    Throws:
    
    java.io.IOException

Class IndexInput

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

IndexInput

Method Detail

readByte

readBytes

readBytes

readInt

readVInt

readLong

readVLong

setModifiedUTF8StringsMode

readString

readChars

skipChars

close

getFilePointer

seek

length

clone

readStringStringMap