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

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

All Implemented Interfaces:

QueryExecutor<S>

Direct Known Subclasses:

FilteredQueryExecutor, FullScanQueryExecutor, IndexedQueryExecutor, IterableQueryExecutor, JoinedQueryExecutor, KeyQueryExecutor, SortedQueryExecutor, UnionQueryExecutor

public abstract class AbstractQueryExecutor<S extends Storable>
extends Object
implements QueryExecutor<S>

AbstractQueryExecutor implements a small set of common QueryExecutor methods.

Author:

Brian S O'Neill

Constructor Summary

AbstractQueryExecutor()

Method Summary

long	count(FilterValues<S> values) Counts results by opening a cursor and skipping entries.
Cursor<S>	fetchSlice(FilterValues<S> values, long from, Long to) Produces a slice via skip and limit cursors.
Class<S>	getStorableType() Returns the storable type that this executor operates on.
protected int	increaseIndent(int indentLevel) Adds a constant amount to the given indent level.
protected void	indent(Appendable app, int indentLevel) Appends spaces to the given appendable.
protected void	newline(Appendable app) Appends a newline character.
boolean	printNative(Appendable app, int indentLevel, FilterValues<S> values) Does nothing and returns false.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.amazon.carbonado.qe.QueryExecutor

fetch, getFilter, getOrdering, printPlan

Constructor Detail

AbstractQueryExecutor

public AbstractQueryExecutor()

Method Detail

getStorableType

public Class<S> getStorableType()

Description copied from interface: QueryExecutor

Returns the storable type that this executor operates on.

Specified by:

getStorableType in interface QueryExecutor<S extends Storable>

fetchSlice

public Cursor<S> fetchSlice(FilterValues<S> values,
                            long from,
                            Long to)
                                      throws FetchException

Produces a slice via skip and limit cursors. Subclasses are encouraged to override with a more efficient implementation.

Specified by:

fetchSlice in interface QueryExecutor<S extends Storable>

Throws:

FetchException

Since:

1.2

count

public long count(FilterValues<S> values)
           throws FetchException

Counts results by opening a cursor and skipping entries. Subclasses are encouraged to override with a more efficient implementation.

Specified by:

count in interface QueryExecutor<S extends Storable>

Throws:

FetchException

printNative

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

Does nothing and returns false.

Specified by:

printNative in interface QueryExecutor<S extends Storable>

values - optional

Returns:

false if not implemented

Throws:

IOException

indent

protected void indent(Appendable app,
                      int indentLevel)
               throws IOException

Appends spaces to the given appendable. Useful for implementing printNative and printPlan.

Throws:

IOException

newline

protected void newline(Appendable app)
                throws IOException

Appends a newline character.

Throws:

IOException

increaseIndent

protected int increaseIndent(int indentLevel)

Adds a constant amount to the given indent level. Useful for implementing printNative and printPlan.