org.biojava.utils
Class AbstractChangeable

java.lang.Object
  extended by org.biojava.utils.AbstractChangeable
All Implemented Interfaces:
Changeable
Direct Known Subclasses:
AbiTraceRenderer, AbstractAlphabet, AbstractAnnotation, AbstractBeadRenderer, AbstractBioEntryDB, AbstractCrossOverFunction, AbstractDistribution, AbstractFeatureHolder, AbstractGeneticAlgorithm, AbstractMutationFunction, AbstractOrganism, AbstractOrthologueSet, AbstractOrthoPairSet, AbstractPopulation, AbstractSequenceDB, AbstractSymbol, AbstractSymbolList, AbstractTaxon, AbstractTerm, BasicFeatureRenderer, BioSQLSequenceDB, CrosshairRenderer, DAS, DASSequence, DummySequence, FeatureBlockSequenceRenderer, FeatureLabelRenderer, FeatureTypes.RepositoryImpl, GFF3Record.Impl, IndexedCount, LabelledSequenceRenderer, LazyFeatureHolder, MergeAnnotation, MultiLineRenderer, NewSimpleAssembly, OffsetRulerRenderer, Ontology.Impl, OntologyTerm.Impl, OverlayAnnotation, OverlayRendererWrapper, PairDistribution, PairwiseDiagonalRenderer, PairwiseFilteringRenderer, PairwiseOverlayRenderer, SequenceDBSearchHit, SequenceDBSearchResult, SequenceDBSearchSubHit, SequenceRendererWrapper, SimpleAssembly, SimpleBioEntry, SimpleBioEntryRelationship, SimpleCodonPref, SimpleComment, SimpleComparableOntology, SimpleComparableTerm, SimpleComparableTriple, SimpleDocRef, SimpleEmissionState, SimpleFeature, SimpleHomology, SimpleLabelRenderer, SimpleMarkovModel, SimpleNamespace, SimpleNCBITaxon, SimpleNote, SimpleRankedCrossRef, SimpleRankedDocRef, SimpleRichAnnotation, SimpleRichFeature, SimpleRichFeatureRelationship, SimpleRichLocation, SimpleSeqSimilaritySearchHit, SimpleSeqSimilaritySearchResult, SimpleSeqSimilaritySearchSubHit, SimpleSequence, SixFrameRenderer, SixFrameZiggyRenderer, StackedFeatureRenderer, TickFeatureRenderer, TranslatedDistribution, WebSequenceDB, WMAsMM, ZiggyFeatureRenderer

public abstract class AbstractChangeable
extends java.lang.Object
implements Changeable

Useful base-class for objects implementing Changeable

Author:
Matthew Pocock, Thomas Down

Constructor Summary
AbstractChangeable()
           
 
Method Summary
 void addChangeListener(ChangeListener cl)
          Add a listener that will be informed of all changes.
 void addChangeListener(ChangeListener cl, ChangeType ct)
          Add a listener that will be informed of changes of a given type.
protected  ChangeSupport generateChangeSupport()
          Called the first time a ChangeSupport object is needed.
protected  ChangeSupport getChangeSupport(ChangeType ct)
          Called to retrieve the ChangeSupport for this object.
protected  boolean hasListeners()
          Deprecated. use hasListeners(ChangeType) if at all possible
protected  boolean hasListeners(ChangeType ct)
          Discover if we have listeners registered for a particular change type.
 boolean isUnchanging(ChangeType ct)
           A particular ChangeType can never be raised by this Changeable.
 void removeChangeListener(ChangeListener cl)
          Remove a listener that was interested in all types of changes.
 void removeChangeListener(ChangeListener cl, ChangeType ct)
          Remove a listener that was interested in a specific types of changes.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

AbstractChangeable

public AbstractChangeable()
Method Detail

hasListeners

protected boolean hasListeners()
Deprecated. use hasListeners(ChangeType) if at all possible

Discover if we have any listeners registered.

Returns:
true if there is at least one listener

hasListeners

protected boolean hasListeners(ChangeType ct)
Discover if we have listeners registered for a particular change type.

Parameters:
ct - the ChangeType we are interested in
Returns:
true if there is at least one listener

generateChangeSupport

protected ChangeSupport generateChangeSupport()
Called the first time a ChangeSupport object is needed. Override this if you want to set the Unchanging set on the ChangeSupport, or if you want to install listeners on other objects when the change system is initialized.

Since:
1.3

getChangeSupport

protected ChangeSupport getChangeSupport(ChangeType ct)
Called to retrieve the ChangeSupport for this object.

Your implementation of this method should have the following structure:

 ChangeSupport cs = super.getChangeSupport(ct);

 if(someForwarder == null && ct.isMatching(SomeInterface.SomeChangeType)) {
   someForwarder = new ChangeForwarder(...

   this.stateVariable.addChangeListener(someForwarder, VariableInterface.AChange);
 }

 return cs;
 
It is usual for the forwarding listeners (someForwarder in this example) to be transient and lazily instantiated. Be sure to register & unregister the forwarder in the code that does the ChangeEvent handling in setter methods.


addChangeListener

public final void addChangeListener(ChangeListener cl)
Description copied from interface: Changeable
Add a listener that will be informed of all changes.

Specified by:
addChangeListener in interface Changeable
Parameters:
cl - the ChangeListener to add

addChangeListener

public final void addChangeListener(ChangeListener cl,
                                    ChangeType ct)
Description copied from interface: Changeable
Add a listener that will be informed of changes of a given type.

Specified by:
addChangeListener in interface Changeable
Parameters:
cl - the ChangeListener
ct - the ChangeType it is to be informed of

removeChangeListener

public final void removeChangeListener(ChangeListener cl)
Description copied from interface: Changeable
Remove a listener that was interested in all types of changes.

Specified by:
removeChangeListener in interface Changeable
Parameters:
cl - a ChangeListener to remove

removeChangeListener

public final void removeChangeListener(ChangeListener cl,
                                       ChangeType ct)
Description copied from interface: Changeable
Remove a listener that was interested in a specific types of changes.

Specified by:
removeChangeListener in interface Changeable
Parameters:
cl - a ChangeListener to remove
ct - the ChangeType that it was interested in

isUnchanging

public final boolean isUnchanging(ChangeType ct)
Description copied from interface: Changeable

A particular ChangeType can never be raised by this Changeable.

If this returns true, then it is guaranteed that change events of this type (and all child types) can never under any circumstances be fired by this Changeable instance. If it returns false, that does not mean that this type of event will or even can be raised, but that it is worth registering listeners incase.

Specified by:
isUnchanging in interface Changeable
Parameters:
ct - the ChangeType to check
Returns:
true if ChangeEvents of this type are guaranteed to never be fired