com.sptci.prevayler.query
Class FetchByIndices<P extends Collection<PrevalentObject>,S extends PrevalentSystem>

java.lang.Object
  com.sptci.prevayler.query.AbstractQuery<P,S>
      com.sptci.prevayler.query.FetchByIndices<P,S>

All Implemented Interfaces:

Query

public class FetchByIndices<P extends Collection<PrevalentObject>,S extends PrevalentSystem>
extends AbstractQuery<P,S>

A query used to fetch prevalent instances by the specified indexed fields.

© Copyright 2008 Sans Pareil Technologies, Inc.

Version:

$Id: FetchByIndices.java 22 2008-11-24 19:04:25Z sptrakesh $

Author:

Rakesh Vidyadharan 2008-07-19

Nested Class Summary

static class

FetchByIndices.AggregationType An enumeration used to indicate whether the query results should represent a union or intersection.

Field Summary

private Map<String,?>	parameters The map of parameters to use to filter the prevalent instances.
private FetchByIndices.AggregationType	resultType The aggregation type to use for the results of the query.
private Class	type The type of the prevalent object that is to be queried.

Constructor Summary

FetchByIndices(Class type, Map<String,?> parameters, FetchByIndices.AggregationType resultType)
Create a new instance of the query with the specified values.

Method Summary

protected P

query(S system, Date timestamp) Execute the query on the prevalent system and return the collection of

Methods inherited from class com.sptci.prevayler.query.AbstractQuery

query

Methods inherited from class java.lang.Object

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

Field Detail

type

private final Class type

The type of the prevalent object that is to be queried.

parameters

private final Map<String,?> parameters

The map of parameters to use to filter the prevalent instances.

resultType

private final FetchByIndices.AggregationType resultType

The aggregation type to use for the results of the query.

Constructor Detail

FetchByIndices

public FetchByIndices(Class type,
                      Map<String,?> parameters,
                      FetchByIndices.AggregationType resultType)

Create a new instance of the query with the specified values.

Parameters:

type - The type to use for the query.

parameters - The map of fields in the prevalent class to use to fetch matching objects.

resultType - The aggregation type to use for the results.

Method Detail

query

protected P query(S system,
                  Date timestamp)
                                               throws PrevalentException

Execute the query on the prevalent system and return the collection of

Specified by:

query in class AbstractQuery<P extends Collection<PrevalentObject>,S extends PrevalentSystem>

Parameters:

system - The prevalent system that is to be acted upon.

timestamp - The timestamp for the query.

Returns:

The collection of prevalent objects matching the specified indexed field.

Throws:

PrevalentException - If errors are encountered while querying the system.

See Also:

PrevalentSystem.fetchUnion(Class, java.util.Map), PrevalentSystem.fetchIntersection(Class, java.util.Map)