java.lang.Object
- it.unimi.di.big.mg4j.index.AbstractBitStreamIndexWriter

All Implemented Interfaces:

IndexWriter

Direct Known Subclasses:

BitStreamHPIndexWriter, BitStreamIndexWriter
```
public abstract class AbstractBitStreamIndexWriter
extends Object
implements IndexWriter
```
An abstract bitstream-based index writer, providing common variables and a basic printStats(PrintStream) implementation.
Compression flags

Implementing subclasses need to know the compression method that they should use to write frequencies, pointers, payloads, counts and positions (and whether to write any of them). This information is passed to the constructor using a suitable flag map (see CompressionFlags).

Since:

1.2

Author:

Sebastiano Vigna

Field Summary

Fields
Modifier and Type	Field	Description
`long`	`bitsForCounts`	The number of bits written for counts.
`long`	`bitsForFrequencies`	The number of bits written for frequencies.
`long`	`bitsForPayloads`	The number of bits written for payloads.
`long`	`bitsForPointers`	The number of bits written for document pointers.
`long`	`bitsForPositions`	The number of bits written for positions.
`protected CompressionFlags.Coding`	`countCoding`	The coding for counts.
`protected long`	`currentTerm`	The current term.
`Map<CompressionFlags.Component,CompressionFlags.Coding>`	`flags`	The flag map.
`protected CompressionFlags.Coding`	`frequencyCoding`	The coding for frequencies.
`protected boolean`	`hasCounts`	Whether this index contains counts.
`protected boolean`	`hasPayloads`	Whether this index contains payloads.
`protected boolean`	`hasPositions`	Whether this index contains positions.
`protected long`	`numberOfDocuments`	The number of documents of the collection to be indexed.
`protected long`	`numberOfOccurrences`	The number of indexed occurrences.
`protected long`	`numberOfPostings`	The number of indexed postings (pairs term/document).
`protected CompressionFlags.Coding`	`pointerCoding`	The coding for pointers.
`protected CompressionFlags.Coding`	`positionCoding`	The coding for positions.

Constructor Summary

Constructors
Constructor	Description
`AbstractBitStreamIndexWriter(long numberOfDocuments, Map<CompressionFlags.Component,CompressionFlags.Coding> flags)`

Method Summary

Modifier and Type Method Description

void printStats(PrintStream stats)
Writes to the given print stream statistical information about the index just built.
- Methods inherited from class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
- Methods inherited from interface it.unimi.di.big.mg4j.index.IndexWriter
  close, newDocumentRecord, newInvertedList, properties, writeDocumentPointer, writeDocumentPositions, writeFrequency, writePayload, writePositionCount, writtenBits

- Field Detail
  - numberOfDocuments
```
protected final long numberOfDocuments
```
    The number of documents of the collection to be indexed.
  - flags
```
public Map<CompressionFlags.Component,CompressionFlags.Coding> flags
```
    The flag map.
  - frequencyCoding
```
protected CompressionFlags.Coding frequencyCoding
```
    The coding for frequencies.
  - pointerCoding
```
protected CompressionFlags.Coding pointerCoding
```
    The coding for pointers.
  - countCoding
```
protected CompressionFlags.Coding countCoding
```
    The coding for counts.
  - positionCoding
```
protected CompressionFlags.Coding positionCoding
```
    The coding for positions.
  - hasPayloads
```
protected final boolean hasPayloads
```
    Whether this index contains payloads.
  - hasCounts
```
protected final boolean hasCounts
```
    Whether this index contains counts.
  - hasPositions
```
protected final boolean hasPositions
```
    Whether this index contains positions.
  - numberOfPostings
```
protected long numberOfPostings
```
    The number of indexed postings (pairs term/document).
  - numberOfOccurrences
```
protected long numberOfOccurrences
```
    The number of indexed occurrences.
  - currentTerm
```
protected long currentTerm
```
    The current term.
  - bitsForFrequencies
```
public long bitsForFrequencies
```
    The number of bits written for frequencies.
  - bitsForPointers
```
public long bitsForPointers
```
    The number of bits written for document pointers.
  - bitsForCounts
```
public long bitsForCounts
```
    The number of bits written for counts.
  - bitsForPayloads
```
public long bitsForPayloads
```
    The number of bits written for payloads.
  - bitsForPositions
```
public long bitsForPositions
```
    The number of bits written for positions.
- Constructor Detail
  - AbstractBitStreamIndexWriter
```
public AbstractBitStreamIndexWriter(long numberOfDocuments,
                                    Map<CompressionFlags.Component,CompressionFlags.Coding> flags)
```
- Method Detail
  - printStats
```
public void printStats(PrintStream stats)
```
    Description copied from interface: IndexWriter
    
    Writes to the given print stream statistical information about the index just built. This method must be called after IndexWriter.close().
    
    Specified by:
    
    printStats in interface IndexWriter
    
    Parameters:
    
    stats - a print stream where statistical information will be written.

Class AbstractBitStreamIndexWriter

Compression flags

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface it.unimi.di.big.mg4j.index.IndexWriter

Field Detail

numberOfDocuments

flags

frequencyCoding

pointerCoding

countCoding

positionCoding

hasPayloads

hasCounts

hasPositions

numberOfPostings

numberOfOccurrences

currentTerm

bitsForFrequencies

bitsForPointers

bitsForCounts

bitsForPayloads

bitsForPositions

Constructor Detail

AbstractBitStreamIndexWriter

Method Detail

printStats