oracle.olapi.data.source
Class Template

java.lang.Object
  |
  +--oracle.olapi.data.source.Template

public abstract class Template

extends java.lang.Object

The basis for creating a Source that an application can dynamically change. An application can use a Template to take the selections made by an end user and produce a Source that represents a query on the data store, or a step in producing a query.

A Template uses the following related objects.

• MetadataState
• DataProvider
• SourceGenerator
• DynamicDefinition

Those objects work together as follows:

• The MetadataState implementation for a Template has fields for storing values.
• An application passes the MetadataState and the DataProvider to the Template constructor. The Template abstract class has methods that create a DynamicDefinition and that get and set the current state of the MetadataState. A class that extends Template adds methods that set the values of the fields of its MetadataState.
• A SourceGenerator implementation has a generateSource method that uses the current state of the data in the MetadataState to produce a Source.
• The Template gets a DynamicDefinition by passing a SourceGenerator to its createDynamicDefinition method.
• The DynamicDefinition has a getSource method that returns the Source produced by the SourceGenerator. That Source is the dynamic Source for the Template.

In the process of producing a Source that represents a single query, an application can use the Source objects produced by various other Template implementations. The application can change the selection of data for any one of the Template objects that comprise the query. Because the DynamicDefinition that gets the Source for a Template is a proxy, the application does not have to recreate all of the component Source objects to produce a Source for the query that includes the new selection. Instead, the application just calls the getSource method of the DynamicDefinition for the Template that produces the query, and the current state of the changed Template component is used in rebuilding the query.

An example of a Template that produces a query is the TopBottomTemplate.java class. In building the query, it uses the Source produced by the SingleSelectionTemplate.java class. A SingleSelectionTemplate object produces a Source that represents the values of a measure that are specified by a set of single members of all but one of the dimensions of the measure. A TopBottomTemplate adds the remaining dimension of the measure. It selects the elements of that dimension that are specified by the criteria represented by the Source for the SingleSelectionTemplate. It sorts the selection in ascending or descending order and produces a Source that represents a specified number of elements from the sorted selection.

The TopBottomTest.java class is a program that creates a SingleSelectionTemplate and a TopBottomTemplate.java. The program produces a Source that specifies the ten products that have the highest number of units sold for the set of single Time, Channel, and Customer dimension values. It prepares and commits the current Transaction. It then creates a Cursor for that Source and displays the values of the Cursor.

The program next changes the value for one of the dimensions specified by the SingleSelectionTemplate, and it changes the number of elements to select and the type of the selection. It prepares and commits the current Transaction, creates a new Cursor for the Source, and displays the values of the Cursor. The values are now the five products that have the lowest number of units sold for the set of the other dimension values.

Before creating the new Cursor, the program does not need to call the getSource method of the DynamicDefinition for either the SingleSelectionTemplate or the TopBottomTemplate. Committing the Transaction automatically updates the dynamic Source objects that those methods returned so that those Source objects represent the current state of the Template objects.

See Also:

DynamicDefinition, MetadataState, SourceGenerator, TransactionProvider

Constructor Summary

protected

Template(MetadataState initialState, DataProvider dataProvider) Creates a new Template.

Method Summary

protected DynamicDefinition	createDynamicDefinition(SourceGenerator sourceGenerator) Creates a DynamicDefinition that acts as a proxy for the SourceDefinition for the Source generated by the SourceGenerator and returned by the getSource method of the DynamicDefinition.
protected MetadataState	getCurrentState() Gets the current state for this Template.
protected MetadataState	getCurrentStateForRead() Gets the actual MetadataState object for this Template rather than a clone of the state.
protected MetadataState	getCurrentStateForWrite() Gets the current state for this Template.
DataProvider	getDataProvider() Gets the DataProvider for this Template.
protected void	setCurrentState(MetadataState state) Specifies a state as the current state for this Template.

Methods inherited from class java.lang.Object

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

Constructor Detail

Template

protected Template(MetadataState initialState,
                   DataProvider dataProvider)
            throws TransactionTypeUnavailableException,
                   TransactionInactiveException

Creates a new Template.

Parameters:

initialState - The MetadataState that stores values for this Template.

dataProvider - The DataProvider created using the current TransactionProvider.

Method Detail

createDynamicDefinition

protected DynamicDefinition createDynamicDefinition(SourceGenerator sourceGenerator)

Creates a DynamicDefinition that acts as a proxy for the SourceDefinition for the Source generated by the SourceGenerator and returned by the getSource method of the DynamicDefinition.

Parameters:

sourceGenerator - The SourceGenerator that generates a Source using the current state of this Template.

Returns:

A DynamicDefinition that provides access to the Source produced by the SourceGenerator.

getCurrentState

protected MetadataState getCurrentState()
                                 throws TransactionalObjectInvalidException,
                                        TransactionTypeUnavailableException,
                                        TransactionInactiveException

Gets the current state for this Template.

Returns:

The current state for this Template.

getCurrentStateForRead

protected MetadataState getCurrentStateForRead()
                                        throws TransactionalObjectInvalidException,
                                               TransactionTypeUnavailableException,
                                               TransactionInactiveException

Gets the actual MetadataState object for this Template rather than a clone of the state. Do not modify the state returned by this method; use it only for read operations.

Returns:

The current state for this Template.

getCurrentStateForWrite

protected MetadataState getCurrentStateForWrite()
                                         throws TransactionalObjectInvalidException,
                                                TransactionTypeUnavailableException,
                                                TransactionInactiveException

Gets the current state for this Template. The returned state is a clone of the actual state, so you can modify it. If you modify it, then you must reset the state by passing it to the setCurrentState method.

Returns:

The current state for this Template.

getDataProvider

public DataProvider getDataProvider()

Gets the DataProvider for this Template.

Returns:

The DataProvider with which this Template was constructed.

setCurrentState

protected void setCurrentState(MetadataState state)
                        throws CursorLockException,
                               WriteLockException,
                               TransactionTypeUnavailableException,
                               TransactionInactiveException

Specifies a state as the current state for this Template.

Parameters:

state - The state to specify as the current state for this Template.