Package org.eclipse.core.databinding

Class UpdateSetStrategy<S,D>

java.lang.Object
org.eclipse.core.databinding.UpdateSetStrategy<S,D>
Type Parameters:
S - the type of the elements on the source side (i.e. the model side if this is a model-to-target update and the target side if this is a target-to-model update)
D - the type of the elements on the destination side (i.e. the target side if this is a model-to-target update and the model side if this is a target-to-model update)
public class UpdateSetStrategy<S,D> extends Object
Customizes a Binding between two observable sets. The following behaviors can be customized via the strategy:
  • Conversion
  • Automatic processing

Conversion:
When elements are added they can be converted to the destination element type.

Automatic processing:
The processing to perform when the source observable changes. This behavior is configured via policies provided on construction of the strategy (e.g. POLICY_NEVER, POLICY_ON_REQUEST, POLICY_UPDATE).

Since:
1.1
See Also:

  • Field Details

    • POLICY_NEVER

      public static final int POLICY_NEVER
      Policy constant denoting that the source observable's state should not be tracked and that the destination observable's state should never be updated.

    • POLICY_ON_REQUEST

      public static final int POLICY_ON_REQUEST
      Policy constant denoting that the source observable's state should not be tracked, but that conversion and updating the destination observable's state should be performed when explicitly requested.

    • POLICY_UPDATE

      public static final int POLICY_UPDATE
      Policy constant denoting that the source observable's state should be tracked, and that conversion and updating the destination observable's state should be performed automatically on every change of the source observable state.

    • provideDefaults

      protected boolean provideDefaults

    • converter

      protected IConverter<? super S,? extends D> converter

  • Constructor Details

    • UpdateSetStrategy

      public UpdateSetStrategy()
      Creates a new update list strategy for automatically updating the destination observable list whenever the source observable list changes. A default converter will be provided. The defaults can be changed by calling one of the setter methods.

    • UpdateSetStrategy

      public UpdateSetStrategy(int updatePolicy)
      Creates a new update list strategy with a configurable update policy. A default converter will be provided. The defaults can be changed by calling one of the setter methods.
      Parameters:
      updatePolicy - one of POLICY_NEVER, POLICY_ON_REQUEST, or POLICY_UPDATE

    • UpdateSetStrategy

      public UpdateSetStrategy(boolean provideDefaults, int updatePolicy)
      Creates a new update list strategy with a configurable update policy. A default converter will be provided if provideDefaults is true, see DataBindingContext. The defaults can be changed by calling one of the setter methods.
      Parameters:
      provideDefaults - if true, default validators and a default converter will be provided based on the observable list's type, see DataBindingContext
      updatePolicy - one of POLICY_NEVER, POLICY_ON_REQUEST, or POLICY_UPDATE

  • Method Details

    • fillDefaults

      protected void fillDefaults(IObservableSet<? extends S> source, IObservableSet<? super D> destination)
      Parameters:
      source - source observable, to be used for its type
      destination - destination observable, to be used for its type

    • getUpdatePolicy

      public int getUpdatePolicy()
      Returns:
      the update policy

    • setConverter

      public UpdateSetStrategy<S,D> setConverter(IConverter<S,D> converter)
      Sets the converter to be invoked when converting added elements from the source element type to the destination element type.

      If the converter throws any exceptions they are reported as validation errors, using the exception message.

      Parameters:
      converter - the new converter
      Returns:
      the receiver, to enable method call chaining

    • doAdd

      protected IStatus doAdd(IObservableSet<? super D> observableSet, D element)
      Adds the given element at the given index to the given observable list. Clients may extend but must call the super implementation.
      Parameters:
      observableSet - the set to add to
      element - element to add
      Returns:
      a status

    • doRemove

      protected IStatus doRemove(IObservableSet<? super D> observableSet, D element)
      Removes the element at the given index from the given observable list. Clients may extend but must call the super implementation.
      Parameters:
      observableSet - the set to remove from
      element - the element to remove
      Returns:
      a status

    • create

      public static <S, D> UpdateSetStrategy<S,D> create(IConverter<S,D> converter)
      Convenience method that creates an UpdateValueStrategy with the given converter. It uses POLICY_UPDATE.
      Parameters:
      converter - the converter
      Returns:
      the update strategy
      Since:
      1.8

    • never

      public static <S, D> UpdateSetStrategy<S,D> never()
      Convenience method that creates an update strategy that never updates its observables, using POLICY_NEVER and no defaults.
      Returns:
      the update strategy
      Since:
      1.8

    • checkAssignable

      protected final void checkAssignable(Object toType, Object fromType, String errorString)

    • createConverter

      protected IConverter<?,?> createConverter(Object fromType, Object toType)
      Tries to create a converter that can convert from values of type fromType. Returns null if no converter could be created. Either toType or modelDescription can be null, but not both.
      Parameters:
      fromType - source type
      toType - target type
      Returns:
      an IConverter, or null if unsuccessful

    • isAssignableFromTo

      protected Boolean isAssignableFromTo(Object fromType, Object toType)
      Returns Boolean.TRUE if the from type is assignable to the to type, or Boolean.FALSE if it not, or null if unknown.
      Parameters:
      fromType - source type to assign
      toType - target type to check assignability against
      Returns:
      whether fromType is assignable to toType, or null if unknown

    • logErrorWhileSettingValue

      protected IStatus logErrorWhileSettingValue(Exception ex)
      Parameters:
      ex - the exception, that was caught
      Returns:
      the validation status

    • convert

      public D convert(S value)
      Converts the value from the source type to the destination type.

      Default implementation will use the setConverter(IConverter), if one exists. If no converter exists no conversion occurs.

      Parameters:
      value - source value to convert
      Returns:
      the converted value