Class TLcdASTERIXFilteredModel

java.lang.Object
com.luciad.model.ALcdModel
com.luciad.format.asterix.TLcdASTERIXFilteredModel
All Implemented Interfaces:
ILcd2DBoundsIndexedModel, ILcd2DBoundsInteractable, ILcdIntegerIndexedModel, ILcdModel, ILcdMultiDimensional, ILcdMultiDimensionalModel, ILcdBounded, ILcdTimeBounded, ILcdLockDependent, ILcdDisposable, Serializable, AutoCloseable

Implements date filtering for ASTERIX Category 8 weather models. This model only exposes weather events for a specific date. If no date is set, a representative subset of the original model is exposed.
Since:
2015.0
See Also:
  • Constructor Details

  • Method Details

    • getUnfilteredModel

      public ILcd2DBoundsIndexedModel getUnfilteredModel()
      Returns the original ASTERIX model which has all the data regardless of the filter.
      Returns:
      the delegated ILcd2DBoundsIndexedModel.
    • size

      public int size()
      Returns the count of the filtered objects.
      Specified by:
      size in interface ILcdIntegerIndexedModel
      Returns:
      the count of the filtered objects.
    • elementAt

      public Object elementAt(int aIndex)
      Returns the element of the filtered objects at the specified index.
      Specified by:
      elementAt in interface ILcdIntegerIndexedModel
      Parameters:
      aIndex - an index into the filtered objects.
      Returns:
      the element at the specified index.
      Throws:
      IndexOutOfBoundsException - if an invalid index was given (aIndex < 0 || aIndex >= size()).
    • indexOf

      public int indexOf(Object aElement)
      Returns the index of the first occurrence of the specified element in the filter objects, or -1 if this model does not contain the element. More formally: returns the smallest i for which this.elementAt(i).equals(aElement).
      Specified by:
      indexOf in interface ILcdIntegerIndexedModel
      Parameters:
      aElement - the element to search for.
      Returns:
      the index of the first occurrence of the specified element in filtered objects, or -1 if this model does not contain the element.
    • setDate

      public void setDate(Date aCurrentValue, int aEventMode)
      Changes the model to only expose weather pictures whose time bounds include the given data. If there is no visible weather picture at a given time, the filter accepts the latest of the previous weather pictures if it exists.
      If no date is set, a representative subset of the original model is exposed.

      Calling this method can change this model. Please refer to ILcdModel's Changing data for threading and locking policies.

      Parameters:
      aCurrentValue - new filter date value
      aEventMode - the mode for sending out the model change event. This can be one of FIRE_NOW, FIRE_LATER or NO_EVENT.
    • getDate

      public Date getDate()
      Returns the current filtering value of the model. This method returns null when:
      Returns:
      The current filtering value of the model, possibly null.
    • getModelReference

      public ILcdModelReference getModelReference()
      Description copied from class: ALcdModel
      Returns the ILcdModelReference describing how the geometry of the elements contained in this model should be interpreted.
      Specified by:
      getModelReference in interface ILcdModel
      Overrides:
      getModelReference in class ALcdModel
      Returns:
      the ILcdModelReference of this ILcdModel.
      See Also:
    • getModelDescriptor

      public ILcdModelDescriptor getModelDescriptor()
      Description copied from class: ALcdModel
      Returns the ILcdModelDescriptor providing meta information about this model and its elements.
      Specified by:
      getModelDescriptor in interface ILcdModel
      Overrides:
      getModelDescriptor in class ALcdModel
      Returns:
      the ILcdModelDescriptor of this ILcdModel. Should not be null.
      See Also:
    • getModelEncoder

      public ILcdModelEncoder getModelEncoder()
      Description copied from class: ALcdModel
      Returns, if available, a model encoder that is capable of encoding this model, (encoder.canEncode(this)), null otherwise.
      Specified by:
      getModelEncoder in interface ILcdModel
      Overrides:
      getModelEncoder in class ALcdModel
      Returns:
      a model encoder that is capable of encoding this model if available, null otherwise.
      See Also:
    • elements

      public Enumeration elements()
      Description copied from interface: ILcdModel
      Returns an enumeration over all elements of this model. The order in which the elements are enumerated is unspecified by default.
      Specified by:
      elements in interface ILcdModel
      Returns:
      an enumeration over all elements of this model.
    • addElement

      public void addElement(Object aElement, int aEventMode)
      Description copied from class: ALcdModel
      Adds the specified element to this model.

      Models that support this operation may place limitations on what elements may be added to this model. For example, implementations that are based on a spatial indexing structure will require that elements implement ILcdBounded.

      When adding an element, the user should make sure that canAddElement(aElement) holds, and that the element's geometry is expressed in the same model reference as this model. It is generally undefined what happens if an invalid element is added.

      Implementations of this interface should clearly specify in their documentation any restrictions on what elements may be added. Although it is unspecified what happens if the preconditions are not met, implementations are encouraged to throw meaningful exceptions (for example, NullPointerException, IllegalArgumentException, ClassCastException, UnsupportedOperationException), whenever possible.

      This implementation always throws an UnsupportedOperationException.

      Specified by:
      addElement in interface ILcdModel
      Overrides:
      addElement in class ALcdModel
      Parameters:
      aElement - the element to be added to this model.
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
      See Also:
    • canAddElement

      public boolean canAddElement(Object aElement)
      Description copied from class: ALcdModel
      Returns true if the specified element can be added to this model, false otherwise.

      Note that this method generally does not validate whether the specified element is expressed in the same model reference as this model. It is the responsibility of the user of this model to make sure this precondition is fulfilled when an element is added to this model.

      This implementation always returns false.

      Specified by:
      canAddElement in interface ILcdModel
      Overrides:
      canAddElement in class ALcdModel
      Parameters:
      aElement - the element to be verified.
      Returns:
      true if the specified element can be added to this model, false otherwise.
    • addElements

      public void addElements(Vector aElements, int aEventMode)
      Description copied from class: ALcdModel
      Adds all of the elements in the specified vector to this model. Models that support this operation may place limitations on what elements may be added to this model. For example, implementations that are based on a spatial indexing structure will require that elements implement ILcdBounded. Implementations of this interface should clearly specify in their documentation any restrictions on what elements may be added.

      The behavior of this operation is undefined if the specified vector is modified while the operation is in progress.

      The specified elements will be added to this model in the order they are specified in the vector. If an element cannot be added, this method will return at the first failure. Succeeding elements won't be added.

      Although it is unspecified what happens if the preconditions are not met, implementations are encouraged to throw meaningful exceptions (for example, NullPointerException, IllegalArgumentException, ClassCastException, UnsupportedOperationException), whenever possible.

      This implementation iterates over all elements in the specified vector, and calls addElement(Object, int) for each element to be added, using event mode NO_EVENT if the specified event mode is NO_EVENT, FIRE_LATER otherwise. If the specified event mode is FIRE_NOW, fireCollectedModelChanges() is called afterwards.

      Specified by:
      addElements in interface ILcdModel
      Overrides:
      addElements in class ALcdModel
      Parameters:
      aElements - the vector of elements to be added to this model.
      aEventMode - the mode for sending the model change events This can be FIRE_LATER or NO_EVENT.
      See Also:
    • removeElement

      public void removeElement(Object aElement, int aEventMode)
      Description copied from class: ALcdModel
      Removes the specified element from this model. If the specified element is not contained in this model, this method has no effect.

      Although it is unspecified what happens if the preconditions are not met, implementations are encouraged to throw meaningful exceptions (for example, NullPointerException, IllegalArgumentException, ClassCastException, UnsupportedOperationException), whenever possible.

      This implementation always throws an UnsupportedOperationException.

      Specified by:
      removeElement in interface ILcdModel
      Overrides:
      removeElement in class ALcdModel
      Parameters:
      aElement - the element to be removed from this model.
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
      See Also:
    • canRemoveElement

      public boolean canRemoveElement(Object aElement)
      Description copied from class: ALcdModel
      Returns true if the specified element can be removed from this model, false otherwise. Note that this method generally does not check whether the specified element is actually contained in this model.

      This implementation always returns false.

      Specified by:
      canRemoveElement in interface ILcdModel
      Overrides:
      canRemoveElement in class ALcdModel
      Parameters:
      aElement - the element to be verified.
      Returns:
      true if the specified element can be removed from this model, false otherwise.
    • removeElements

      public void removeElements(Vector aElements, int aEventMode)
      Description copied from class: ALcdModel
      Removes all of the elements in the specified vector from this model. If one of the elements in the specified vector is not contained in this model, this element will be ignored.

      The behavior of this operation is undefined if the specified vector is modified while the operation is in progress.

      The specified elements will be removed from this model in the order they are specified in the vector. If an element cannot be removed, this method will return at the first failure. Succeeding elements won't be removed.

      Although it is unspecified what happens if the preconditions are not met, implementations are encouraged to throw meaningful exceptions (for example, NullPointerException, IllegalArgumentException, ClassCastException, UnsupportedOperationException), whenever possible.

      This implementation iterates over all elements in the specified vector, and calls removeElement(Object, int) for each element to be removed, using event mode NO_EVENT if the specified event mode is NO_EVENT, FIRE_LATER otherwise. If the specified event mode is FIRE_NOW, fireCollectedModelChanges() is called afterwards.

      Specified by:
      removeElements in interface ILcdModel
      Overrides:
      removeElements in class ALcdModel
      Parameters:
      aElements - the vector of elements to be removed from this model.
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
      See Also:
    • removeAllElements

      public void removeAllElements(int aEventMode)
      Description copied from class: ALcdModel
      Removes all elements from this model.

      If an element cannot be removed, this method will return at the first failure. Succeeding elements won't be removed.

      Although it is unspecified what happens if the preconditions are not met, implementations are encouraged to throw meaningful exceptions (for example, NullPointerException, IllegalArgumentException, ClassCastException, UnsupportedOperationException), whenever possible.

      This implementation iterates over all elements in the model, and calls removeElement(Object, int) for each element to be removed, using event mode NO_EVENT if the specified event mode is NO_EVENT, FIRE_LATER otherwise. If the specified event mode is FIRE_NOW, fireCollectedModelChanges() is called afterwards.

      Specified by:
      removeAllElements in interface ILcdModel
      Overrides:
      removeAllElements in class ALcdModel
      Parameters:
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
    • elementChanged

      public void elementChanged(Object aElement, int aEventMode)
      Description copied from class: ALcdModel
      Notifies this model that the specified element has changed.

      This implementation calls TLcdModelChangedEventSupport#elementChanged(Object, int).

      Specified by:
      elementChanged in interface ILcdModel
      Overrides:
      elementChanged in class ALcdModel
      Parameters:
      aElement - the element that has changed.
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
    • elementsChanged

      public void elementsChanged(Vector aElements, int aEventMode)
      Description copied from class: ALcdModel
      Notifies this model that the elements in the specified vector have changed.

      This implementation calls TLcdModelChangedEventSupport#elementsChanged(java.util.Vector, int).

      Specified by:
      elementsChanged in interface ILcdModel
      Overrides:
      elementsChanged in class ALcdModel
      Parameters:
      aElements - the vector of elements that have changed.
      aEventMode - the mode for sending out the model change event. This can be FIRE_LATER or NO_EVENT.
    • fireCollectedModelChanges

      public void fireCollectedModelChanges()
      Description copied from class: ALcdModel
      Notifies all listeners that are registered on this model of all the changes that have been collected between the previous notification and now.

      This implementation calls #TLcdModelChangedEventSupport#fireCollectedModelChanges().

      Specified by:
      fireCollectedModelChanges in interface ILcdModel
      Overrides:
      fireCollectedModelChanges in class ALcdModel
      See Also:
    • addModelListener

      public void addModelListener(ILcdModelListener aModelListener)
      Description copied from class: ALcdModel

      Registers the specified model listener to receive notifications of model changes on this model.

      Model changes are sent out when an element has been added, removed or changed. Model changes can be sent out individually, grouped or silently applied without notifications, depending on the ILcdFireEventMode that was specified with the change.

      In case you need to register a listener which keeps a reference to an object with a shorter life-time than this model, you can use a ALcdWeakModelListener instance as model listener.

      This implementation calls TLcdModelChangedEventSupport#addModelListener(ILcdModelListener).

      Specified by:
      addModelListener in interface ILcdModel
      Overrides:
      addModelListener in class ALcdModel
      Parameters:
      aModelListener - the ILcdModelListener to register on this model.
      See Also:
    • removeModelListener

      public void removeModelListener(ILcdModelListener aModelListener)
      Description copied from class: ALcdModel
      Unregisters the specified model listener so that it no longer receives notifications of model changes on this model.

      This implementation calls TLcdModelChangedEventSupport#removeModelListener(ILcdModelListener).

      Specified by:
      removeModelListener in interface ILcdModel
      Overrides:
      removeModelListener in class ALcdModel
      Parameters:
      aModelListener - the ILcdModelListener to remove.
      See Also:
    • dispose

      public void dispose()
      Description copied from class: ALcdModel
      Disposes of this model and allows it to release any system resources that it is holding. The result of calling any other method (other than finalize) on this model subsequent to a call to this method is undefined.

      When a model disposer has been provided it is called, otherwise this method does nothing. When overriding this method it is recommended to call super.dispose().

      Specified by:
      dispose in interface ILcdDisposable
      Specified by:
      dispose in interface ILcdModel
      Overrides:
      dispose in class ALcdModel
      See Also:
    • applyOnInteract2DBounds

      public int applyOnInteract2DBounds(ILcdBounds aBounds, boolean aStrictInteract, ILcdFunction aFunctionToApply, double aPrecisionX, double aPrecisionY)
      Description copied from interface: ILcd2DBoundsIndexedModel
      Applies the specified function to all the model elements of which the 2D bounds overlap with the specified bounds. By default, the order in which the function is applied on the elements is unspecified and depends on the implementation.

      The return value of the specified function is used as a stop criterion: the spatial query is interrupted if the function returns false.

      Specified by:
      applyOnInteract2DBounds in interface ILcd2DBoundsIndexedModel
      Parameters:
      aBounds - the rectangle to test overlap with.
      aStrictInteract - if false, the spatial search may return more elements than the ones strictly overlapping; if true, the search only returns the elements that are overlapping. The latter mode is more precise, but it may be slower.
      aFunctionToApply - the function to apply on each element that overlaps with the given bounds. The return value of the specified function is used as a stop criterion: the spatial query is interrupted if the function returns false.
      aPrecisionX - the precision required in the x dimension, expressed in model units. For example, for a cartesian grid system expressed in meters, the values should be expressed in meters as well, for a geodetic coordinate system the accuracy values should be expressed in degrees.

      The precision is useful in combination with multi-leveled data (multiple representations of the same object, but with varying accuracy), so that the most appropriate accuracy level can be used. 0 means best possible accuracy, but it might trigger lazy-loaded implementations to load lots of data.

      aPrecisionY - the precision required in the y dimension, expressed in model units.
      Returns:
      the number of elements to which the ILcdFunction has been applied.
    • applyOnInteract2DBounds

      public int applyOnInteract2DBounds(ILcdBounds aBounds, boolean aStrictInteract, ILcdFunction aFunctionToApply, double aPrecisionX, double aPrecisionY, double aMinSizeX, double aMinSizeY, boolean aIncludePoints)
      Description copied from interface: ILcd2DBoundsInteractable
      Applies the specified function to all the elements of which the 2D bounds overlap with the specified bounds. The order in which the function is applied on the elements is unspecified and depends on the implementation.

      Only elements that have at least the specified minimal size in the x dimension or in the y dimension are considered. This can be useful for quickly eliminating elements that are too small to be visible in a view, for instance. If required, an exception can be made for point elements, which have a size of 0 by 0. They can be forced to be considered, even though they would always be rejected as being too small for any sizes larger than 0.

      The return value of the specified function is used as a stop criterion: the spatial query will be interrupted as soon as the function returns false for an element it was applied on.

      Specified by:
      applyOnInteract2DBounds in interface ILcd2DBoundsIndexedModel
      Specified by:
      applyOnInteract2DBounds in interface ILcd2DBoundsInteractable
      Parameters:
      aBounds - the rectangle to test overlap with.
      aStrictInteract - if false, the spatial search may return more elements than the ones strictly overlapping; if true, the search only returns the elements that are overlapping. The latter mode is more precise, but it may be slower.
      aFunctionToApply - the function to apply on each element that overlaps with the given bounds.
      aPrecisionX - the precision required in the x dimension, expressed in model units. For example, for a cartesian grid system expressed in meters, the values should be expressed in meters as well, for a geodetic coordinate system the accuracy values should be expressed in degrees.

      The precision is useful in combination with multi-leveled data (multiple representations of the same object, but with varying accuracy), so that the most appropriate accuracy level can be used. 0 means best possible accuracy, but it might trigger lazy-loaded implementations to load lots of data.

      aPrecisionY - the precision required in the y dimension, expressed in model units.
      aMinSizeX - the minimal element size in the x dimension (as in ILcdBounds.getWidth()), expressed in model units. Elements that are smaller than this size will be skipped. This may, for example, be useful when improving the efficiency of painting elements by skipping elements that are smaller than some threshold (e.g. one pixel, converted to model units).
      aMinSizeY - the minimal element size in the y dimension (as in ILcdBounds.getHeight()), expressed in model units.
      aIncludePoints - if true, zero-sized elements (points) are considered as well, even though they might be smaller than the minimum size.
      Returns:
      the number of elements to which the ILcdFunction has been applied.
    • getBounds

      public ILcdBounds getBounds()
      Description copied from interface: ILcdBounded
      Returns the ILcdBounds by which the geometry of this ILcdBounded object is bounded.

      If the geometry does not allow retrieving valid bounds (for example a polyline with 0 points) the return value is unspecified. It is highly recommended to return an undefined bounds. You can create undefined bounds using the default constructors of TLcdLonLatBounds or TLcdXYBounds.

      Specified by:
      getBounds in interface ILcdBounded
      Returns:
      the ILcdBounds by which the geometry of this ILcdBounded object is bounded.
    • getPossibleDates

      public List<Date> getPossibleDates()
      Deprecated.
      Use getDimensions() and ILcdDimension.getValues() instead.
      Generates and returns possible filtering values from each element's begin and end time information.
      Returns:
      list of filterable values, or an empty list if there are no values
    • getTimeBounds

      public ILcdTimeBounds getTimeBounds()
      Description copied from interface: ILcdTimeBounded
      Returns the ILcdTimeBounds by which this object is bounded.
      Specified by:
      getTimeBounds in interface ILcdTimeBounded
      Returns:
      the ILcdTimeBounds by which this object is bounded.
    • getDimensions

      public List<TLcdDimension<Date>> getDimensions()
      Description copied from interface: ILcdMultiDimensional
      Gets a list of dimensions, for example time or height, over which this multi-dimensional object is defined. Each dimension defines an axis, its possible values, and the range of possible values. The values of the dimension axes are all the possible values this multi-dimensional object can be filtered on. An empty list means that the instance is not dimensionally filterable.
      Specified by:
      getDimensions in interface ILcdMultiDimensional
      Returns:
      a list dimensions (axes and their possible values) over which this multi-dimensional object is defined, possibly empty but never null.
      See Also:
    • applyDimensionFilter

      public void applyDimensionFilter(TLcdDimensionFilter aFilter, int aEventMode)
      Description copied from interface: ILcdMultiDimensionalModel
      Applies a given dimensional filter and fires an event accordingly. The given filter may specify one interval per axis. The filter may contain more or less axes than the model supports.
      • If the filter contains more axes than the model supports, the model should ignore those axes.
      • If the filter contains less axes than the model supports, the model should reset to its default for those axes.
      In particular, in case of the empty filter, the model should reset to the default filter. The default filter is typically an accept-all filter, but the specific behavior depends on the model implementation.

      Filtering behavior
      In practice, filtering behavior and the default filter depend on the type of the model:

      • Vector models, such as NVG or ASTERIX, have multiple elements, where every element is a domain object. Each element has a validity defined by an interval, for example a temporal interval on a time axis. The filtered model will only contain the elements that match the filter. When a new filter is applied, events will be fired as elements are removed or added based on the new filter. The default filter in this case is 'no filter', which means that all elements match the filter and the model behaves as if unfiltered. In case no elements match the filter, the model will be empty.
      • Raster models, such as NetCDF, have a single or a couple of model elements, where every model element corresponds with exactly one image. Internally, each element is possibly backed up by multiple ALcdImage instances, every one of which is valid within a certain interval. An implementation of this interface needs to make sure that
        • a model element only corresponds with exactly one of these images, based on the currently configured filter.
        • the model element's image is available through ALcdImage.fromDomainObject(java.lang.Object). We advise to use the 'has-an-image' paradigm to expose this image, because it allows for faster updates in a Lightspeed view.
        • changes in filtering are correctly applied. When a filter is changed, it must either replace the element with a new element, or when the 'has-an-image' paradigm is used, it must replace the image that is exposed by the model element. When a filter doesn't match anything, it must make sure that there is no element present in the model. Using 'has-an-image' with a null image is not a valid way to express this.
        Typically, the default image will be the 'first' image.
      Example: consider a NetCDF model with an initial filter which selects the 'first' image. The NetCDF model has two dimensions: time and vertical position. Suppose a filter is applied for a specific time and vertical position: the model's domain object selects the corresponding image and fires an appropriate event. Now suppose a filter is applied for a specific time but no vertical position: multiple images match for multiple vertical positions, but the model selects the 'first'.

      Filter matching
      Matching intervals happens based on TLcdDimensionInterval.overlaps(com.luciad.multidimensional.TLcdDimensionInterval<T>, com.luciad.multidimensional.TLcdDimensionInterval<T>). The rationale for this is the following:

      • Each element has a validity defined by an interval, for example on a time axis.
      • Using the filter, you're asking the model to "match everything which is valid in the filter interval(s)", which corresponds to the meaning of overlap.

      Locking
      This method should typically be called from within a write lock:

      
          try (TLcdLockUtil.Lock lock = TLcdLockUtil.writeLock(model) {
            ...
            model.applyDimensionFilter(filter, ILcdModel.FIRE_LATER);
            ...
          } finally {
            model.fireCollectedModelChanges();
          }
       
      The most common exception to this rule is when you're creating a model initially and no-one has a reference to it yet: in that case, it's safe to not lock at all and use ILcdModel.NO_EVENT.

      No snapping
      Implementations should not 'snap' to the intervals defined by the filter in case no elements match. There shall be no snapping to nearest, previous or next. Instead, the result must be 'empty' (or 'image is null' in case of raster models). If you need to snap a filter interval to an actual interval the model has to offer, you should use TLcdDimensionFilter.createSnappingFilter(com.luciad.multidimensional.ILcdMultiDimensionalModel, com.luciad.multidimensional.TLcdDimensionFilter.SnapMode) to create a snapped filter.

      Differences with createSnappingFilter
      As its name suggests, the primary purpose of the utility method createSnappingFilter is to create a filter which 'snaps' to filter intervals so that there is always at least one match. But the method does more than just that. Here is a list of differences between using and not using createSnappingFilter:

      Behavior applyDimensionFilter createSnappingFilter->applyDimensionFilter
      Snapping Never, possibly resulting in no matches Snaps to intervals defined by the model if needed, such that there is always at least one match
      Supported snap modes None Nearest, previous, next, or none (null)
      Filter has less axes than supported by model Reset to default for those axes Keep the last current filter value for those axes, so that there are minimal model changes
      Empty filter Reset to default filter Keep current filter, so that there are no model changes
      ILcdModel which is not ILcdMultiDimensionalModel Not supported Checks instance of ILcdMultiDimensionalModel, leaves others alone
      Specified by:
      applyDimensionFilter in interface ILcdMultiDimensionalModel
      Parameters:
      aFilter - The dimensional filter, possibly empty but never null.
      aEventMode - The mode of the event that should be triggered when the value of the filter parameters changes.
      See Also:
    • getDimensionFilter

      public TLcdDimensionFilter getDimensionFilter()
      Returns the current filtering value of the model. Asterix models use Date as filtering value. This method returns null when:
      Specified by:
      getDimensionFilter in interface ILcdMultiDimensionalModel
      Returns:
      The current filtering value of the model, possibly null.
    • getDependentObjects

      public List<Object> getDependentObjects()
      Description copied from interface: ILcdLockDependent
      Returns the objects that must be locked along with this object. TLcdLockUtilfirst locks all objects returned by this method before locking this object.
      Specified by:
      getDependentObjects in interface ILcdLockDependent
      Returns:
      the objects that must be locked along with this object.