MonotonicBlockPackedWriter (Jackrabbit Oak 1.71-SNAPSHOT API)

java.lang.Object
- org.apache.lucene.util.packed.MonotonicBlockPackedWriter

```
public final class MonotonicBlockPackedWriter
extends Object
```
A writer for large monotonically increasing sequences of positive longs.
The sequence is divided into fixed-size blocks and for each block, values are modeled after a linear function f: x → A × x + B. The block encodes deltas from the expected values computed from this function using as few bits as possible. Each block has an overhead between 6 and 14 bytes.
Format:
- <BLock>^BlockCount
- BlockCount: ⌈ ValueCount / BlockSize ⌉
- Block: <Header, (Ints)>
- Header: <B, A, BitsPerValue>
- B: the B from f: x → A × x + B using a variable-length long
- A: the A from f: x → A × x + B encoded using Float.floatToIntBits(float) on 4 bytes
- BitsPerValue: a variable-length int
- Ints: if BitsPerValue is 0, then there is nothing to read and all values perfectly match the result of the function. Otherwise, these are the zigzag-encoded packed deltas from the expected value (computed from the function) using exaclty BitsPerValue bits per value
See Also:

MonotonicBlockPackedReader

Field Summary

Fields
Modifier and Type	Field	Description
`protected byte[]`	`blocks`
`protected boolean`	`finished`
`protected int`	`off`
`protected long`	`ord`
`protected DataOutput`	`out`
`protected long[]`	`values`

Constructor Summary

Constructors
Constructor Description

MonotonicBlockPackedWriter(DataOutput out, int blockSize)
Sole constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(long l)`	Append a new long.
`void`	`finish()`	Flush all buffered data to disk.
`protected void`	`flush()`
`long`	`ord()`	Return the number of values which have been added.
`void`	`reset(DataOutput out)`	Reset this writer to wrap `out`.
`protected void`	`writeValues(int bitsRequired)`

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

Field Detail

out
```
protected DataOutput out
```

values
```
protected final long[] values
```

blocks
```
protected byte[] blocks
```

off
```
protected int off
```

ord
```
protected long ord
```

finished
```
protected boolean finished
```

Constructor Detail
- MonotonicBlockPackedWriter
```
public MonotonicBlockPackedWriter(DataOutput out,
                                  int blockSize)
```
  Sole constructor.
  
  Parameters:
  
  blockSize - the number of values of a single block, must be a power of 2

Method Detail
- add
```
public void add(long l)
         throws IOException
```
  Append a new long.
  
  Throws:
  
  IOException
- flush
```
protected void flush()
              throws IOException
```
  Throws:
  
  IOException
- reset
```
public void reset(DataOutput out)
```
  Reset this writer to wrap out. The block size remains unchanged.
- finish
```
public void finish()
            throws IOException
```
  Flush all buffered data to disk. This instance is not usable anymore after this method has been called until reset(DataOutput) has been called.
  
  Throws:
  
  IOException
- ord
```
public long ord()
```
  Return the number of values which have been added.
- writeValues
```
protected final void writeValues(int bitsRequired)
                          throws IOException
```
  Throws:
  
  IOException