com.unister.semweb.drums.bucket
Class Bucket<Data extends AbstractKVStorable>

java.lang.Object
  com.unister.semweb.drums.bucket.Bucket<Data>

Type Parameters:

Data - an implementation of AbstractKVStorable, e.g. GeneralStorable

public class Bucket<Data extends AbstractKVStorable>
extends java.lang.Object

An instance of this class is a container of AbstractKVStorables.

Author:

Martin Nettling, Nils Thieme

Field Summary

int	elementsInBucket the number of elements in this bucket.

Constructor Summary

Bucket(int bucketId, DRUMSParameterSet<Data> gp)
Constructor.

Method Summary

boolean	add(AbstractKVStorable toAdd) Adds one AbstractKVStorable-object.
boolean	contains(Data element)
int	freeMemory() This method frees the allocated memory.
Data[]	getBackend() Returns the in backend stored AbstractKVStorables.
int	getBucketId()
long	getCreationTime()
java.nio.ByteBuffer	getElementAt(int index)
Bucket<Data>	getEmptyBucketWithSameProperties() returns a new empty Bucket with the same properties of this bucket
int	size()

Methods inherited from class java.lang.Object

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

Field Detail

elementsInBucket

public int elementsInBucket

the number of elements in this bucket. For faster access, should be public

Constructor Detail

Bucket

public Bucket(int bucketId,
              DRUMSParameterSet<Data> gp)

Constructor. Needs to know the id of the Bucket and the maximum size of the Bucket.

Parameters:

bucketId - the identification number of this bucket. Used in BucketContainer and other classes

gp - a pointer to the DRUMSParameterSet

Method Detail

getEmptyBucketWithSameProperties

public Bucket<Data> getEmptyBucketWithSameProperties()
                                                                         throws FileLockException,
                                                                                java.io.IOException

returns a new empty Bucket with the same properties of this bucket

Returns:

a new Bucket with the same bucketId

Throws:

java.io.IOException

FileLockException

getBucketId

public int getBucketId()

Returns:

the id of the bucket. The id is value between 0 and numberOfBuckets (see BucketContainer)

add

public boolean add(AbstractKVStorable toAdd)

Adds one AbstractKVStorable-object. This method have to be synchronized, because it is possible to access the backend in the same moment with the function getBackend().

Parameters:

toAdd - the Data to add

Returns:

true, if adding the element to the buffer was successful

contains

public boolean contains(Data element)

Parameters:

element - the element to look for

Returns:

true, if this bucket, contains the given element

getElementAt

public java.nio.ByteBuffer getElementAt(int index)

Parameters:

index - the index of the element in the bucket

Returns:

a ByteBuffer containing the requested element. The returned ByteBuffer is in read-only mode.

getBackend

public Data[] getBackend()

Returns the in backend stored AbstractKVStorables. First it rebuilds all objects from their byte-arrays and then sorts them.

Returns:

AbstractKVStorable[] all AbstractKVStorables ascending sorted

size

public int size()

Returns:

the number of elements, actually stored

freeMemory

public int freeMemory()

This method frees the allocated memory.

Returns:

the number of bytes which are available now

getCreationTime

public long getCreationTime()

Returns:

the creation time of this bucket.