Top Description Fields Constructors Methods

com.dlsc.gemsfx.binding

public Class GeneralAggregatedListBinding<T, S, U, R>

Class Inheritance

extends ObjectBinding<R>

java.lang.Object
javafx.beans.binding.ObjectExpression
javafx.beans.binding.ObjectBinding
com.dlsc.gemsfx.binding.GeneralAggregatedListBinding

Type Parameters

<T>: the type of elements in the source list
<S>: the type of elements in the nested lists
<U>: the intermediate aggregation type
<R>: the final result type

Imports

javafx.beans.binding.ObjectBinding, javafx.collections.ListChangeListener, .ObservableList, .WeakListChangeListener, java.util.List, .Objects, java.util.function.Function, java.util.stream.Stream

Represents a generic binding that aggregates results from a nested collection structure. This class listens to changes not only in the top-level observable list of type T but also in the nested observable lists of type S associated with each T. The binding performs aggregation operations over these lists to produce a final result of type R, making it ideal for applications with dynamic data models.

This class is designed to work with a stable source of ObservableLists provided by the itemToListFunction. It is crucial for the correct operation of this binding that the same instance of ObservableList is returned for any given item in the lifecycle of that item. Changing the underlying ObservableList instances during the lifecycle can lead to unpredictable behavior and potential memory leaks.

Important Considerations:

Stable List References: The itemToListFunction must consistently return the same ObservableList instance for any given item throughout its lifecycle. If the lists are stored in properties such as javafx.beans.property.ObjectProperty or javafx.beans.property.SimpleListProperty, ensure that these properties do not get reassigned to new lists as this can disrupt the behavior of the binding and lead to memory leaks.
Managing Listeners: Proper management of listeners is critical. Ensure that any list obtained from the itemToListFunction has listeners appropriately added or removed. This may require overriding property setters or employing property change listeners to manage list listeners when the property's value changes.

Field Summary

Modifier and Type	Field and Description
private final Function<List<S>, U>	aggregationFunction
private final Function<Stream<U>, R>	finalAggregationFunction
private final Function<T, ObservableList<S>>	itemToListFunction
private final ListChangeListener<Object>	nestedListChangeListener
private final ObservableList<T>	source
private final ListChangeListener<T>	sourceListChangeListener
private final WeakListChangeListener<Object>	weakNestedListChangeListener
private final WeakListChangeListener<T>	weakSourceListChangeListener

Constructor Summary

Access	Constructor and Description
public	GeneralAggregatedListBinding(ObservableList<T> The observable list of source items. This list should be stable during the lifecycle of the binding, meaning that elements should not be replaced with different instances to ensure reliable behavior. source, Function<T, ObservableList<S>> A function that maps each element of the source list, T, to an observable list of S. This function must consistently return the same instance of ObservableList for any given item throughout its lifecycle to avoid erratic behavior and potential memory leaks. itemToListFunction, Function<List<S>, U> A function that aggregates a list of S into an intermediate result U, based on the current data in those lists. aggregationFunction, Function<Stream<U>, R> A function that aggregates a list of intermediate results U into the final result R, which represents the aggregate of the entire structure. finalAggregationFunction) Constructs a new GeneralAggregatedListBinding.

Access

Constructor and Description

public

GeneralAggregatedListBinding(ObservableList<T>

The observable list of source items. This list should be stable during the lifecycle of the binding, meaning that elements should not be replaced with different instances to ensure reliable behavior.

source, Function<T, ObservableList<S>>

A function that maps each element of the source list, T, to an observable list of S. This function must consistently return the same instance of ObservableList for any given item throughout its lifecycle to avoid erratic behavior and potential memory leaks.

itemToListFunction, Function<List<S>, U>

A function that aggregates a list of S into an intermediate result U, based on the current data in those lists.

aggregationFunction, Function<Stream<U>, R>

A function that aggregates a list of intermediate results U into the final result R, which represents the aggregate of the entire structure.

finalAggregationFunction)

Constructs a new GeneralAggregatedListBinding.

Method Summary

Modifier and Type	Method and Description
protected R	computeValue() Implements abstract javafx.beans.binding.ObjectBinding.computeValue. Calculates the current value of this binding.
private void	convertToListAndSafeAddListener(T item)
private void	convertToListAndSafeRemoveListener(T item)
public void	dispose() Overrides javafx.beans.binding.ObjectBinding.dispose. Implements javafx.beans.binding.Binding.dispose. A default implementation of `dispose()` that is empty.
private void	safeAddListener(ObservableList<S> list)
private void	safeRemoveListener(ObservableList<S> list)

Inherited from javafx.beans.binding.ObjectBinding:: addListener addListener allowValidation bind get getDependencies invalidate isObserved isValid onInvalidating removeListener removeListener toString unbind

Field Detail

aggregationFunction	back to summary
private final Function<List<S>, U> aggregationFunction

finalAggregationFunction	back to summary
private final Function<Stream<U>, R> finalAggregationFunction

itemToListFunction	back to summary
private final Function<T, ObservableList<S>> itemToListFunction

nestedListChangeListener	back to summary
private final ListChangeListener<Object> nestedListChangeListener

source	back to summary
private final ObservableList<T> source

sourceListChangeListener	back to summary
private final ListChangeListener<T> sourceListChangeListener

weakNestedListChangeListener	back to summary
private final WeakListChangeListener<Object> weakNestedListChangeListener

weakSourceListChangeListener	back to summary
private final WeakListChangeListener<T> weakSourceListChangeListener

Constructor Detail

GeneralAggregatedListBinding	back to summary
public GeneralAggregatedListBinding(ObservableList<T> source, Function<T, ObservableList<S>> itemToListFunction, Function<List<S>, U> aggregationFunction, Function<Stream<U>, R> finalAggregationFunction) Constructs a new GeneralAggregatedListBinding. This constructor initializes the binding based on a source list, a function to map each element of the source to an observable list, and two aggregation functions. It sets up listeners on the source list and all nested lists, allowing the binding to react dynamically to changes within these lists. Parameters source:ObservableList<T> The observable list of source items. This list should be stable during the lifecycle of the binding, meaning that elements should not be replaced with different instances to ensure reliable behavior. itemToListFunction:Function<T, ObservableList<S>> A function that maps each element of the source list, T, to an observable list of S. This function must consistently return the same instance of ObservableList for any given item throughout its lifecycle to avoid erratic behavior and potential memory leaks. aggregationFunction:Function<List<S>, U> A function that aggregates a list of S into an intermediate result U, based on the current data in those lists. finalAggregationFunction:Function<Stream<U>, R> A function that aggregates a list of intermediate results U into the final result R, which represents the aggregate of the entire structure.

GeneralAggregatedListBinding

back to summary

public GeneralAggregatedListBinding(ObservableList<T> source, Function<T, ObservableList<S>> itemToListFunction, Function<List<S>, U> aggregationFunction, Function<Stream<U>, R> finalAggregationFunction)

Constructs a new GeneralAggregatedListBinding. This constructor initializes the binding based on a source list, a function to map each element of the source to an observable list, and two aggregation functions. It sets up listeners on the source list and all nested lists, allowing the binding to react dynamically to changes within these lists.

Parameters

source:ObservableList<T>: The observable list of source items. This list should be stable during the lifecycle of the binding, meaning that elements should not be replaced with different instances to ensure reliable behavior.
itemToListFunction:Function<T, ObservableList<S>>: A function that maps each element of the source list, T, to an observable list of S. This function must consistently return the same instance of ObservableList for any given item throughout its lifecycle to avoid erratic behavior and potential memory leaks.
aggregationFunction:Function<List<S>, U>: A function that aggregates a list of S into an intermediate result U, based on the current data in those lists.
finalAggregationFunction:Function<Stream<U>, R>: A function that aggregates a list of intermediate results U into the final result R, which represents the aggregate of the entire structure.

Method Detail

computeValue back to summary

computeValue	back to summary
protected R computeValue() Implements abstract javafx.beans.binding.ObjectBinding.computeValue. Doc from javafx.beans.binding.ObjectBinding.computeValue. Calculates the current value of this binding. Classes extending `ObjectBinding` have to provide an implementation of `computeValue`. Annotations @Override

protected R computeValue()

Implements abstract javafx.beans.binding.ObjectBinding.computeValue.

Doc from javafx.beans.binding.ObjectBinding.computeValue.

Calculates the current value of this binding.

Classes extending ObjectBinding have to provide an implementation of computeValue.

Annotations

@Override

convertToListAndSafeAddListener	back to summary
private void convertToListAndSafeAddListener(T item)

convertToListAndSafeRemoveListener	back to summary
private void convertToListAndSafeRemoveListener(T item)

dispose back to summary

dispose	back to summary
public void dispose() Overrides javafx.beans.binding.ObjectBinding.dispose. Implements javafx.beans.binding.Binding.dispose. Doc from javafx.beans.binding.ObjectBinding.dispose. A default implementation of `dispose()` that is empty. Annotations @Override

public void dispose()

Overrides javafx.beans.binding.ObjectBinding.dispose.

Implements javafx.beans.binding.Binding.dispose.

Doc from javafx.beans.binding.ObjectBinding.dispose.

A default implementation of dispose() that is empty.

Annotations

@Override

safeAddListener	back to summary
private void safeAddListener(ObservableList<S> list)

safeRemoveListener	back to summary
private void safeRemoveListener(ObservableList<S> list)