org.das2.dataset
Class ConstantDataSetDescriptor

java.lang.Object
  org.das2.dataset.DataSetDescriptor
      org.das2.dataset.ConstantDataSetDescriptor

All Implemented Interfaces:

Displayable

public class ConstantDataSetDescriptor
extends DataSetDescriptor

This class wraps a DataSet to use where DataSetDescriptors are required. This trivially returns the wrapped DataSet regardless of the getDataSet parameters. Originally this class was used with Renderers, which needed a DataSetDescriptor for their operation. Now that they interact only with DataSets, and this class should not be used with them, use Renderer.setDataSet instead.

Field Summary

Fields inherited from class org.das2.dataset.DataSetDescriptor

properties

Constructor Summary

ConstantDataSetDescriptor(DataSet ds)
Creates a new instance of ConstantDataSetDescriptor

Method Summary

DataSet	getDataSet(Datum start, Datum end, Datum resolution, ProgressMonitor monitor) Retrieve the dataset for this interval and resolution.
DataSet	getDataSetImpl(Datum start, Datum end, Datum resolution, ProgressMonitor monitor) getDataSetImpl implements the getDataSet for this DataSetDescriptor implementation.
Units	getXUnits()
void	requestDataSet(Datum start, Datum end, Datum resolution, ProgressMonitor monitor, java.lang.Object lockObject) Requests that a dataSet be loaded, and that the dataSet be returned via a DataSetUpdate event.

Methods inherited from class org.das2.dataset.DataSetDescriptor

addDataSetUpdateListener, create, fireDataSetUpdateEvent, getDataSetCache, getDataSetID, getListIcon, getListLabel, getProperty, removeDataSetUpdateListener, requestDataSet, reset, setDefaultCaching, setProperties

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantDataSetDescriptor

public ConstantDataSetDescriptor(DataSet ds)

Creates a new instance of ConstantDataSetDescriptor

Method Detail

getDataSetImpl

public DataSet getDataSetImpl(Datum start,
                              Datum end,
                              Datum resolution,
                              ProgressMonitor monitor)
                       throws DasException

Description copied from class: DataSetDescriptor

getDataSetImpl implements the getDataSet for this DataSetDescriptor implementation. The getDataSet call of the abstract DataSetDescriptor uses this routine to satisfy requests and fill its cache. This caching may be disabled via setDefaultCaching. To satisfy the request, a DataSet should be returned with an x tag range that contains start and end, with a resolution finer than that requested.

Specified by:

getDataSetImpl in class DataSetDescriptor

Parameters:

start - beginning of range for the request.

end - end of the range for the request.

resolution - the resolution requirement for the reqeust. null may be used to request the finest resolution available or intrinic resolution.

Throws:

DasException

getDataSet

public DataSet getDataSet(Datum start,
                          Datum end,
                          Datum resolution,
                          ProgressMonitor monitor)
                   throws DasException

Description copied from class: DataSetDescriptor

Retrieve the dataset for this interval and resolution. The contract for this function is that identical start,end,resolution parameters will yield an identical dataSet, except for when an DataSetUpdate has been fired in the meantime. null for the data resolution indicates that the data should be returned at its "intrinsic resolution" if such a resolution exists.

Overrides:

getDataSet in class DataSetDescriptor

Throws:

DasException

getXUnits

public Units getXUnits()

Specified by:

getXUnits in class DataSetDescriptor

Returns:

the x units of the DataSetDescriptor that parameterize the data. This is used to identify dataSet requests.

requestDataSet

public void requestDataSet(Datum start,
                           Datum end,
                           Datum resolution,
                           ProgressMonitor monitor,
                           java.lang.Object lockObject)

Description copied from class: DataSetDescriptor

Requests that a dataSet be loaded, and that the dataSet be returned via a DataSetUpdate event. The @param lockObject is an object that is dependent on the load, for example, the DasCanvas, and will be passed in to the request processor. If the dataSet is available in interactive time, then the dataSetUpdate may be fired on the same thread as the request is made.

Overrides:

requestDataSet in class DataSetDescriptor