org.apache.giraph.edge

Class LongDiffArray

java.lang.Object

org.apache.giraph.edge.LongDiffArray

All Implemented Interfaces:

org.apache.hadoop.io.Writable

@NotThreadSafe
public class LongDiffArray
extends Object
implements org.apache.hadoop.io.Writable

Compressed list array of long ids. Note: this implementation is optimized for space usage, but random access and edge removals are expensive. Users of this class should explicitly call trim() function to compact in-memory representation after all updates are done. Compacting object is expensive so should only be done once after bulk update. Compaction can also be caused by serialization attempt or by calling iterator()

Constructor Summary

Constructors

Constructor and Description
LongDiffArray()

Method Summary

Modifier and Type	Method and Description
void	add(long id) Add a value
void	initialize() Initialize array
void	initialize(int capacity) Initialize with a given capacity
Iterator<org.apache.hadoop.io.LongWritable>	iterator() Returns an iterator that reuses objects.
void	readFields(DataInput in)
void	remove(long id) Remove a given value
void	setUseUnsafeSerialization(boolean useUnsafeSerialization) Set whether to use unsafe serailization
int	size() The number of stored ids
void	trim() This function takes all recent updates and stores them efficiently.
void	write(DataOutput out)

Methods inherited from class java.lang.Object

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

Constructor Detail

LongDiffArray

public LongDiffArray()

Method Detail

setUseUnsafeSerialization

public void setUseUnsafeSerialization(boolean useUnsafeSerialization)

Set whether to use unsafe serailization

Parameters:

useUnsafeSerialization - use unsafe serialization

initialize

public void initialize(int capacity)

Initialize with a given capacity

Parameters:

capacity - capacity

initialize

public void initialize()

Initialize array

add

public void add(long id)

Add a value

Parameters:

id - id to add

remove

public void remove(long id)

Remove a given value

Parameters:

id - id to remove

size

public int size()

The number of stored ids

Returns:

the number of stored ids

iterator

public Iterator<org.apache.hadoop.io.LongWritable> iterator()

Returns an iterator that reuses objects.

Returns:

Iterator

write

public void write(DataOutput out)
           throws IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

IOException

trim

public void trim()

This function takes all recent updates and stores them efficiently. It is safe to call this function multiple times.