edu.upc.dama.dex.core
Class Objects

java.lang.Object
  edu.upc.dama.dex.core.Objects

All Implemented Interfaces:

java.io.Closeable, java.lang.Iterable, java.util.Collection, java.util.Set

public class Objects
extends java.lang.Object
implements java.io.Closeable, java.util.Set

Object identifier collection.

It stores a collection of DEX object identifiers as a set of long values where there is no duplicated values. The memory managemnt is done by the parent GraphPool.

This class should be used just to store large collections. Otherwise, it is strongly recommended to use common classes from the Java API.

This class is NOT thread safe.

Known problems:

Object identifiers cannot be removed from Objects while Iterators are still opened. That is, a code as follows may have unexpected and fatal results:

 Objects objs = ...
 Objects.Iterator it = objs.iterator();
 while (it.hasNext()) {
   long oid = it.next();
   if (...) {
     objs.remove(oid);
   }
 }
 it.close();
 objs.close();
 

Also, in case Objects has been obtained directly from a Graph, this collection cannot be updated through its original Graph. That is, a code as follows may have unexpected and fatal results:

 Objects objs = graph.select(attr, Graph.OPERATION_EQ, value); // or something similar
 Objects.Iterator it objs.iterator();
 while (it.hasNext()) {
   long oid = it.next();
   if (...) {
     graph.setAttribute(oid, attr, newvalue);
   }
 }
 it.close();
 objs.close();
 

Author:

Sparsity Technologies

Nested Class Summary

static class	Objects.Combine Deprecated. As of release 1.2, replace by Objects.COMBINE_UNION, Objects.COMBINE_DIFFERENCE and Objects.COMBINE_INTERSECTION.
class	Objects.Iterator Iterator to traverse the object identifier in a collection.

Field Summary

static short	COMBINE_DIFFERENCE Difference combine operation.
static short	COMBINE_INTERSECTION Intersection combine operation.
static short	COMBINE_UNION Union combine operation.

Constructor Summary

Objects(Session sess)
Creates a new instance of Objects.

Objects(Session sess, Objects objs)
Creates a new instance of Objects which is a copy of the given one.

Objects(Session sess, Objects objs1, Objects objs2, Objects.Combine c)
Deprecated. As of release 1.2, replace by Objects.Objects(Session,Objects,Objects,short).

Objects(Session sess, Objects objs1, Objects objs2, short combine)
Creates a new instance of Objects which is the combination of the two given collections.

Method Summary

boolean	add(long oid) Adds an object identifier to the collection.
boolean	add(java.lang.Long e)
boolean	addAll(java.util.Collection clctn)
void	clear()
void	close() Closes the collection and all their non-closed iterators.
boolean	contains(java.lang.Object o)
boolean	containsAll(java.util.Collection clctn)
long	difference(Objects objs) Performs the difference operation with the given collection.
static Objects	difference(Session sess, Objects objs1, Objects objs2) Creates a new instance of Objects which is the difference of the two given collections.
boolean	exists(long oid) Gets whether the object identifier exists in the collection or not.
long	first() Gets the first object identifier in the collection.
Session	getSession() Gets the parent Session instance.
long	intersection(Objects objs) Performs the intersection operation with the given collection.
static Objects	intersection(Session sess, Objects objs1, Objects objs2) Creates a new instance of Objects which is the intersection of the two given collections.
boolean	isEmpty()
boolean	isOpen() Gets if the Objects instance is open.
Objects.Iterator	iterator() Gets an Objects.Iterator.
Objects.Iterator	iterator(long startPosition) Gets an Objects.Iterator.
Objects.Iterator	iteratorFromOID(long oid) Gets an Objects.Iterator pointing tot the given object.
long	next(long oid, boolean exists) Gets the next object identifier in the collection from the given one.
boolean	remove(long oid) Removes the given object identifier.
boolean	remove(java.lang.Object o)
boolean	removeAll(java.util.Collection clctn)
boolean	retainAll(java.util.Collection clctn)
static Objects	sample(Session sess, Objects src, Objects exclude, long samples) Creates a new instance of Objects which is a sample of a given collection excluding the objects of another one.
int	size()
long	sizeLong() As Objects.size() but it returns a long which can be larger than Integer.MAX_VALUE.
java.lang.Object[]	toArray()
java.lang.Object[]	toArray(java.lang.Object[] ts)
long	union(Objects objs) Performs the union operation with the given collection.
static Objects	union(Session sess, Objects objs1, Objects objs2) Creates a new instance of Objects which is the union of the two given collections.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Set

equals, hashCode

Field Detail

COMBINE_UNION

public static final short COMBINE_UNION

Union combine operation.

See Also:

Constant Field Values

COMBINE_INTERSECTION

public static final short COMBINE_INTERSECTION

Intersection combine operation.

See Also:

Constant Field Values

COMBINE_DIFFERENCE

public static final short COMBINE_DIFFERENCE

Difference combine operation.

See Also:

Constant Field Values

Constructor Detail

Objects

public Objects(Session sess)

Creates a new instance of Objects.

It creates a new empty collection.

Parameters:

sess - Parent Session.

Objects

public Objects(Session sess,
               Objects objs)

Creates a new instance of Objects which is a copy of the given one.

Parameters:

sess - Parent Session instance.

objs - Objects instance.

Objects

public Objects(Session sess,
               Objects objs1,
               Objects objs2,
               short combine)

Creates a new instance of Objects which is the combination of the two given collections.

Parameters:

sess - Parent Session.

objs1 - Objects instance.

objs2 - Objects instance.

combine - Combine operation. It must be Objects.COMBINE_UNION, Objects.COMBINE_INTERSECTION, or Objects.COMBINE_DIFFERENCE.

Objects

@Deprecated
public Objects(Session sess,
                          Objects objs1,
                          Objects objs2,
                          Objects.Combine c)

Deprecated. As of release 1.2, replace by Objects.Objects(Session,Objects,Objects,short).

Creates a new instance of Objects which is the combination of the two given collections.

Parameters:

sess - Parent Session.

objs1 - Objects instance.

objs2 - Objects instance.

c - Combine operation.

Method Detail

union

public static Objects union(Session sess,
                            Objects objs1,
                            Objects objs2)

Creates a new instance of Objects which is the union of the two given collections.

Parameters:

sess - Parent Session.

objs1 - Objects instance.

objs2 - Objects instance.

Returns:

A new Objects which is the union of the two given collections.

intersection

public static Objects intersection(Session sess,
                                   Objects objs1,
                                   Objects objs2)

Creates a new instance of Objects which is the intersection of the two given collections.

Parameters:

sess - Parent Session.

objs1 - Objects instance.

objs2 - Objects instance.

Returns:

A new Objects which is the intersection of the two given collections.

difference

public static Objects difference(Session sess,
                                 Objects objs1,
                                 Objects objs2)

Creates a new instance of Objects which is the difference of the two given collections.

Parameters:

sess - Parent Session.

objs1 - Objects instance.

objs2 - Objects instance.

Returns:

A new Objects which is the difference of the two given collections.

getSession

public Session getSession()

Gets the parent Session instance.

Returns:

The parent Session instance.

isOpen

public boolean isOpen()

Gets if the Objects instance is open.

Only opened Objects instances can execute methods, otherwise they will fail.

Returns:

true if the Objects instance is open, false otherwise.

close

public void close()

Closes the collection and all their non-closed iterators.

It is important to close Objects as soon as possible to free its memory resources.

Specified by:

close in interface java.io.Closeable

See Also:

Objects.Iterator

sizeLong

public long sizeLong()

As Objects.size() but it returns a long which can be larger than Integer.MAX_VALUE.

Returns:

Number of elements into the collection.

add

public boolean add(long oid)

Adds an object identifier to the collection.

Parameters:

oid - Object identifier.

Returns:

true if the object identifier is successfully added to the collection or false if the object identifier was alredy in the collection.

exists

public boolean exists(long oid)

Gets whether the object identifier exists in the collection or not.

Parameters:

oid - Object identifier.

Returns:

true if the object identifier exists in the collection or false otherwise.

first

public long first()

Gets the first object identifier in the collection.

The first object identifier is that with the smaller value. The collection must have at least one element.

Returns:

The first object identifier in the collection.

next

public long next(long oid,
                 boolean exists)

Gets the next object identifier in the collection from the given one.

Parameters:

oid - Object identifier.

exists - If true, oid must exists into the collection.

Returns:

The next object identifier in the collection from the given one.

remove

public boolean remove(long oid)

Removes the given object identifier.

Parameters:

oid - Object identifier.

Returns:

true if the object identifier is successfully removed, false if the object identifier was not in the collection.

clear

public void clear()

Specified by:

clear in interface java.util.Collection

Specified by:

clear in interface java.util.Set

union

public long union(Objects objs)

Performs the union operation with the given collection.

All the object identifiers in the objs collection are added to the calling instance collection.

Parameters:

objs - Object identifier collection.

Returns:

The resulting size of the calling instance collection.

intersection

public long intersection(Objects objs)

Performs the intersection operation with the given collection.

Only those object identifiers which are present in the objs collection and in the calling instance collection will remain in the calling instance collection, the others will be removed from the calling instance collection.

Parameters:

objs - Object identifier collection.

Returns:

The resulting size of the calling instance collection.

difference

public long difference(Objects objs)

Performs the difference operation with the given collection.

All object identifiers from the calling instance collection will remain in the calling instance collection but those which are present in the objs collection.

Parameters:

objs - Object identifier collection.

Returns:

The resulting size of the calling instance collection.

sample

public static Objects sample(Session sess,
                             Objects src,
                             Objects exclude,
                             long samples)

Creates a new instance of Objects which is a sample of a given collection excluding the objects of another one.

It creates a collection.

Parameters:

sess - Parent Session.

src - Source Objects to be sampled.

exclude - Objects to be excluded.

samples - The number of object samples to be taken.

Returns:

New Objects collection.

iterator

public Objects.Iterator iterator()

Gets an Objects.Iterator.

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in interface java.util.Set

Returns:

An Objects.Iterator.

iterator

public Objects.Iterator iterator(long startPosition)

Gets an Objects.Iterator.

Parameters:

startPosition - The number of objects to skip from the beginning [0..Size).

Returns:

An Objects.Iterator.

iteratorFromOID

public Objects.Iterator iteratorFromOID(long oid)

Gets an Objects.Iterator pointing tot the given object.

Parameters:

oid - The identifier of the object.

Returns:

An Objects.Iterator.

size

public int size()

Specified by:

size in interface java.util.Collection

Specified by:

size in interface java.util.Set

See Also:

Objects.sizeLong()

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Collection

Specified by:

isEmpty in interface java.util.Set

contains

public boolean contains(java.lang.Object o)

Specified by:

contains in interface java.util.Collection

Specified by:

contains in interface java.util.Set

toArray

public java.lang.Object[] toArray()

Specified by:

toArray in interface java.util.Collection

Specified by:

toArray in interface java.util.Set

toArray

public java.lang.Object[] toArray(java.lang.Object[] ts)

Specified by:

toArray in interface java.util.Collection

Specified by:

toArray in interface java.util.Set

add

public boolean add(java.lang.Long e)

Specified by:

add in interface java.util.Collection

Specified by:

add in interface java.util.Set

remove

public boolean remove(java.lang.Object o)

Specified by:

remove in interface java.util.Collection

Specified by:

remove in interface java.util.Set

containsAll

public boolean containsAll(java.util.Collection clctn)

Specified by:

containsAll in interface java.util.Collection

Specified by:

containsAll in interface java.util.Set

addAll

public boolean addAll(java.util.Collection clctn)

Specified by:

addAll in interface java.util.Collection

Specified by:

addAll in interface java.util.Set

retainAll

public boolean retainAll(java.util.Collection clctn)

Specified by:

retainAll in interface java.util.Collection

Specified by:

retainAll in interface java.util.Set

removeAll

public boolean removeAll(java.util.Collection clctn)

Specified by:

removeAll in interface java.util.Collection

Specified by:

removeAll in interface java.util.Set