org.garret.perst
Class Projection<From extends IPersistent,To extends IPersistent>

java.lang.Object
  java.util.AbstractCollection
      java.util.AbstractSet
          java.util.HashSet
              org.garret.perst.Projection

All Implemented Interfaces:

java.lang.Cloneable, java.util.Collection, java.lang.Iterable, java.io.Serializable, java.util.Set

public class Projection<From extends IPersistent,To extends IPersistent>

extends java.util.HashSet<To>

Class use to project selected objects using relation field. For all selected objects (specified by array ort iterator), value of specified field (of IPersistent, array of IPersistent, Link or Relation type) is inspected and all referenced object for projection (duplicate values are eliminated)

See Also:

Serialized Form

Constructor Summary

Projection()
Default constructor of projection.

Projection(java.lang.Class type, java.lang.String fieldName)
Constructor of projection specified by class and field name of projected objects

Method Summary

boolean	add(To obj) Add object to the set
void	join(Projection<From,To> prj) Join this projection with another projection.
void	project(java.util.Collection<From> c) Project specified selection
void	project(From obj) Project specified object
void	project(From[] selection) Project specified selection
void	project(java.util.Iterator<From> selection) Project specified selection
void	reset() Reset projection - clear result of preceding project and join operations
void	setProjectionField(java.lang.Class type, java.lang.String fieldName) Specify class of the projected objects and projection field name
IPersistent[]	toPersistentArray() Get result of preceding project and join operations

Methods inherited from class java.util.HashSet

add, clear, clone, contains, isEmpty, iterator, remove, size

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

addAll, containsAll, equals, hashCode, removeAll, retainAll, toArray, toArray

Constructor Detail

Projection

public Projection()

Default constructor of projection. This constructor should be used only when you are going to derive your class from Projection and redefine map method in it or specify type and fieldName later using setProjectionField method

Projection

public Projection(java.lang.Class type,
                  java.lang.String fieldName)

Constructor of projection specified by class and field name of projected objects

Parameters:

type - base class for selected objects

fieldName - field name used to perform projection

Method Detail

add

public boolean add(To obj)

Add object to the set

Overrides:

add in class java.util.HashSet

Parameters:

obj - objet to be added

join

public void join(Projection<From,To> prj)

Join this projection with another projection. Result of this join is set of objects present in both projections.

project

public void project(java.util.Collection<From> c)

Project specified selection

Parameters:

c - selection iterator specifying selected objects

project

public void project(From obj)

Project specified object

Parameters:

obj - selected object

project

public void project(From[] selection)

Project specified selection

Parameters:

selection - array with selected object

project

public void project(java.util.Iterator<From> selection)

Project specified selection

Parameters:

selection - iterator specifying selected objects

reset

public void reset()

Reset projection - clear result of preceding project and join operations

setProjectionField

public void setProjectionField(java.lang.Class type,
                               java.lang.String fieldName)

Specify class of the projected objects and projection field name

Parameters:

type - base class for selected objects

fieldName - field name used to perform projection

toPersistentArray

public IPersistent[] toPersistentArray()

Get result of preceding project and join operations

Returns:

array of objects