edu.brook.ascape.util
Class VectorSelection

java.lang.Object
  |
  +--java.util.Observable
        |
        +--edu.brook.ascape.util.VectorSelection

Direct Known Subclasses:

DrawFeatureSelection

public class VectorSelection

extends java.util.Observable

implements java.util.Observer, java.lang.Cloneable, java.io.Serializable

A selection imposed on a Vector. Methods are provided for selecting elements, and notifying observers of changes in selction status, but not changes in the underlying vector class. (This class will be generalized for all collections, and collection observer functionality will probably be provided when collections are integrated into the main engine, which should happen after Java 2 (JDK 1.2) becomes commonplace.) Important: because Vectors are not observable, underlying vectors must call the update method on any enclosing vector selection if any changes are made to them. If you want to be able to select Vector elements based on name, implement the HasName interface. Should be thread safe, but not tested. Performance emphasis is on accessing selected elements, not setting selection. Accessing selected elements should be quite fast since an array of selected elements is stored locally.

Since:

1.0

Version:

1.0.1 2/22/99

See Also:

HasName, DataSelection, Serialized Form

Field Summary

protected boolean[]	elemsSelected An array for selection status for all elements in the vector.
protected int	selectedCount The number of elements currently selected.
protected java.lang.Object[]	selectedElems An array of selected elements of the vector.
protected java.util.Vector	vector The underlying vector that we are imposing a seleciton upon.

Constructor Summary

VectorSelection()
Construct a new VectorSelection.

VectorSelection(java.util.Vector vector)
Construct a new VectorSelection.

Method Summary

void	addElement(java.lang.Object object) Add an elelemnt to the underlying vector.
void	addElement(java.lang.Object object, boolean select) Add an elelemnt to the underlying vector.
void	clear() Sets selection to none, unselecting every element in the vector.
void	clearSelection() Sets selection to none, unselecting every element in the vector.
java.lang.Object	clone() Performs shallow copy, cloning this vector selection, with a shared backing vector.
int	getIndexInVector(int index) Returns the index in the vector of the object at the provided selection index.
java.lang.Object	getSelectedElement(int index) Returns the object at the provided selection index.
java.lang.Object[]	getSelection() Returns the current complete seleciton of vector elements.
int	getSelectionSize() Returns the number of selected elements.
java.util.Vector	getVector() Returns the underlying vector.
boolean	isSelected(int index) Is the object at the supplied index selected in this selection?
boolean	isSelected(java.lang.Object elem) Is the supplied object selected in this selection?
void	select(java.lang.String name) Selects the object with the supplied name.
void	selectAll() Selects every element in the vector.
void	setSelected(int index, boolean select) Sets the object at the supplied index to the selection status indicated.
void	setSelected(java.lang.Object elem, boolean select) Sets the supplied object to the selection status indicated.
void	setSelected(java.lang.String name, boolean select) Sets the object with the supplied name to the selection status indicated.
void	setVector(java.util.Vector vector) Set the underlying vector for this selection.
java.lang.String	toString() Returns a string represention of the vector selection.
void	unselect(java.lang.String name) Unselects the object with the supplied name.
void	update() Updates the entire vector, retaining current element selection status and relative selection order.
void	update(java.util.Observable observed, java.lang.Object arg) Normally, notifies the selection that a change in the backing vector has occured.

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Field Detail

vector

protected java.util.Vector vector

The underlying vector that we are imposing a seleciton upon.

selectedElems

protected java.lang.Object[] selectedElems

An array of selected elements of the vector.

elemsSelected

protected boolean[] elemsSelected

An array for selection status for all elements in the vector.

selectedCount

protected int selectedCount

The number of elements currently selected.

Constructor Detail

VectorSelection

public VectorSelection()

Construct a new VectorSelection.

VectorSelection

public VectorSelection(java.util.Vector vector)

Construct a new VectorSelection.

Parameters:

vector - the underlying vector

Method Detail

setVector

public void setVector(java.util.Vector vector)

Set the underlying vector for this selection. If any underlying elements are the same as in a previous vector, their selection status should be retained.

getVector

public java.util.Vector getVector()

Returns the underlying vector.

getSelection

public java.lang.Object[] getSelection()

Returns the current complete seleciton of vector elements.

addElement

public void addElement(java.lang.Object object,
                       boolean select)

Add an elelemnt to the underlying vector. Automatically calls update.

Parameters:

the - object to add

should - the object be intitially selected?

addElement

public void addElement(java.lang.Object object)

Add an elelemnt to the underlying vector. Automatically calls update. Object is initially selected.

update

public void update()

Updates the entire vector, retaining current element selection status and relative selection order. May be costly, especially for large collections, as this class is optimized for the selection access case. Calls to this method may be batched, that is, you can make a number of changes to the underlying vecotr and call update one time.

isSelected

public boolean isSelected(java.lang.Object elem)

Is the supplied object selected in this selection?

Parameters:

elem - the object to determine selection status for

Returns:

true if the item is selected, false if the item is not selected or is not in the list

isSelected

public boolean isSelected(int index)

Is the object at the supplied index selected in this selection?

Parameters:

index - the vector index of the object to determine selection status for

Returns:

true if the item is selected

selectAll

public void selectAll()

Selects every element in the vector.

clearSelection

public void clearSelection()

Sets selection to none, unselecting every element in the vector.

clear

public void clear()

Sets selection to none, unselecting every element in the vector.

select

public void select(java.lang.String name)

Selects the object with the supplied name.

Parameters:

name - the name of the series to set select status for

unselect

public void unselect(java.lang.String name)

Unselects the object with the supplied name.

Parameters:

name - the name of the series to set select status for

setSelected

public void setSelected(int index,
                        boolean select)

Sets the object at the supplied index to the selection status indicated.

Parameters:

index - the vector index of the object to set select status for

select - true to select the item, false to unselect it

setSelected

public void setSelected(java.lang.String name,
                        boolean select)

Sets the object with the supplied name to the selection status indicated. Warning: Expects Vector members to implement of HaveName.

Parameters:

name - the name of the series to set select status for

select - true to select the item, false to unselect it

Throws:

ClassCastException - if vector elements are not instances of HaveName

setSelected

public void setSelected(java.lang.Object elem,
                        boolean select)

Sets the supplied object to the selection status indicated.

Parameters:

elem - the object to set selection status for

select - true to select the item, false to unselect it

Throws:

java.lang.RuntimeException - if the element does not exist in the vector

getSelectionSize

public int getSelectionSize()

Returns the number of selected elements.

getIndexInVector

public int getIndexInVector(int index)

Returns the index in the vector of the object at the provided selection index.

Parameters:

index - the selection index to get the vector index for

getSelectedElement

public java.lang.Object getSelectedElement(int index)

Returns the object at the provided selection index.

Parameters:

index - the index in this selection of the series

update

public void update(java.util.Observable observed,
                   java.lang.Object arg)

Normally, notifies the selection that a change in the backing vector has occured. Not used at the moment, because Vector isn't observable. Will probably be implmented when java collections are fully implemeneted in ascape.

Specified by:

update in interface java.util.Observer

clone

public java.lang.Object clone()

Performs shallow copy, cloning this vector selection, with a shared backing vector.

Overrides:

clone in class java.lang.Object

toString

public java.lang.String toString()

Returns a string represention of the vector selection.

Overrides:

toString in class java.lang.Object