com.amazon.carbonado.qe
Class UnionQueryExecutor<S extends Storable>

java.lang.Object
  com.amazon.carbonado.qe.AbstractQueryExecutor<S>
      com.amazon.carbonado.qe.UnionQueryExecutor<S>

All Implemented Interfaces:

QueryExecutor<S>

public class UnionQueryExecutor<S extends Storable>
extends AbstractQueryExecutor<S>

QueryExecutor which wraps several others and unions the results.

Author:

Brian S O'Neill

See Also:

UnionCursor

Constructor Summary

UnionQueryExecutor(List<QueryExecutor<S>> executors)

UnionQueryExecutor(List<QueryExecutor<S>> executors, OrderingList<S> totalOrdering)

UnionQueryExecutor(QueryExecutor<S>... executors)

Method Summary

Cursor<S>	fetch(FilterValues<S> values) Returns a new cursor using the given filter values.
Filter<S>	getFilter() Returns the combined filter of the wrapped executors.
OrderingList<S>	getOrdering() Returns the result ordering of this QueryExecutor.
boolean	printNative(Appendable app, int indentLevel, FilterValues<S> values) Prints native queries of the wrapped executors.
boolean	printPlan(Appendable app, int indentLevel, FilterValues<S> values) Prints the query plan to any appendable, if applicable.

Methods inherited from class com.amazon.carbonado.qe.AbstractQueryExecutor

count, fetchSlice, getStorableType, increaseIndent, indent, newline

Methods inherited from class java.lang.Object

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

Constructor Detail

UnionQueryExecutor

public UnionQueryExecutor(QueryExecutor<S>... executors)

Parameters:

executors - executors to wrap, each must have the exact same total ordering

Throws:

IllegalArgumentException - if any parameter is null or if ordering doesn't match

UnionQueryExecutor

public UnionQueryExecutor(List<QueryExecutor<S>> executors)

Parameters:

executors - executors to wrap, each must have the exact same total ordering

Throws:

IllegalArgumentException - if any executors is null or if ordering doesn't match

UnionQueryExecutor

public UnionQueryExecutor(List<QueryExecutor<S>> executors,
                          OrderingList<S> totalOrdering)

Parameters:

executors - executors to wrap, each must have the exact same total ordering

totalOrdering - effective total ordering of executors

Throws:

IllegalArgumentException - if executors is null

Method Detail

fetch

public Cursor<S> fetch(FilterValues<S> values)
                                 throws FetchException

Description copied from interface: QueryExecutor

Returns a new cursor using the given filter values.

Throws:

FetchException

getFilter

public Filter<S> getFilter()

Returns the combined filter of the wrapped executors.

Returns:

query filter, never null

getOrdering

public OrderingList<S> getOrdering()

Description copied from interface: QueryExecutor

Returns the result ordering of this QueryExecutor.

Returns:

query ordering in an unmodifiable list

printNative

public boolean printNative(Appendable app,
                           int indentLevel,
                           FilterValues<S> values)
                    throws IOException

Prints native queries of the wrapped executors.

Specified by:

printNative in interface QueryExecutor<S extends Storable>

Overrides:

printNative in class AbstractQueryExecutor<S extends Storable>

values - optional

Returns:

false if not implemented

Throws:

IOException

printPlan

public boolean printPlan(Appendable app,
                         int indentLevel,
                         FilterValues<S> values)
                  throws IOException

Description copied from interface: QueryExecutor

Prints the query plan to any appendable, if applicable.

values - optional

Returns:

false if not implemented

Throws:

IOException