com.hazelcast.map.impl.query

Class QueryResult

java.lang.Object

com.hazelcast.map.impl.query.QueryResult

All Implemented Interfaces:

Result<QueryResult>, DataSerializable, IdentifiedDataSerializable, Iterable<QueryResultRow>

public class QueryResult
extends Object
implements Result<QueryResult>, Iterable<QueryResultRow>

Represents a result of the query execution in the form of an iterable collection of rows.

There are two modes of the result construction, the selection of the mode is controlled by the orderAndLimitExpected parameter:

1. When orderAndLimitExpected is true, this indicates that the call to the orderAndLimit(com.hazelcast.query.PagingPredicate, java.util.Map.Entry<java.lang.Integer, java.util.Map.Entry>) method is expected on behalf of the paging predicate involved in the query. In this case, the intermediate result is represented as a collection of queryable entries to allow the comparison of the items using the comparator of the paging predicate. After the call to completeConstruction(java.util.Collection<java.lang.Integer>), all the queryable entries are converted to rows and the result is ready to be provided to the client.
2. When orderAndLimitExpected is false, this indicates that no calls to the orderAndLimit(com.hazelcast.query.PagingPredicate, java.util.Map.Entry<java.lang.Integer, java.util.Map.Entry>) method are expected. In this case, the intermediate result is represented directly as a collection of rows and no further conversion is performed.

Constructor Summary

Constructors

Constructor and Description
QueryResult() Constructs an empty result for the purposes of deserialization.
QueryResult(IterationType iterationType, Projection projection, SerializationService serializationService, long resultLimit, boolean orderAndLimitExpected) Constructs an empty result.

Method Summary

Modifier and Type	Method and Description
void	add(QueryableEntry entry) Adds the given entry to this result.
void	addRow(QueryResultRow row) Adds the given row into this result.
void	combine(QueryResult result) Combines the given result with this result modifying this result.
void	completeConstruction(Collection<Integer> partitionIds) Completes the construction of this result.
QueryResult	createSubResult() Creates a new empty sub result of the same type as this result.
int	getFactoryId() Returns DataSerializableFactory factory ID for this class.
int	getId() Returns type identifier for this class.
Collection<Integer>	getPartitionIds()
List<QueryResultRow>	getRows()
boolean	isEmpty()
Iterator<QueryResultRow>	iterator()
void	onCombineFinished() Invoked when the result combining phase is finished.
void	orderAndLimit(PagingPredicate pagingPredicate, Map.Entry<Integer,Map.Entry> nearestAnchorEntry) Performs the order-and-limit operation on this result for the given paging predicate.
void	readData(ObjectDataInput in) Reads fields from the input stream
void	setPartitionIds(Collection<Integer> partitionIds) Sets the partition IDs of this result.
int	size()
void	writeData(ObjectDataOutput out) Writes object fields to output stream

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

QueryResult

public QueryResult()

Constructs an empty result for the purposes of deserialization.

QueryResult

public QueryResult(IterationType iterationType,
                   Projection projection,
                   SerializationService serializationService,
                   long resultLimit,
                   boolean orderAndLimitExpected)

Constructs an empty result.

Parameters:

iterationType - the iteration type of the query for which this result is constructed for.

projection - the projection of the query for which this result is constructed for.

serializationService - the serialization service associated with the query for which this result is constructed for.

resultLimit - the upper limit on the number of items that can be added to this result.

orderAndLimitExpected - the flag to signal that the call to the orderAndLimit(com.hazelcast.query.PagingPredicate, java.util.Map.Entry<java.lang.Integer, java.util.Map.Entry>) method is expected, see the class javadoc for more details.

Method Detail

iterator

public Iterator<QueryResultRow> iterator()

Specified by:

iterator in interface Iterable<QueryResultRow>

size

public int size()

Returns:

the size of this result.

isEmpty

public boolean isEmpty()

Returns:

true if this result is empty, false otherwise.

addRow

public void addRow(QueryResultRow row)

Adds the given row into this result.

Parameters:

row - the row to add.

add

public void add(QueryableEntry entry)

Adds the given entry to this result.

Specified by:

add in interface Result<QueryResult>

Parameters:

entry - the entry to add.

Throws:

QueryResultSizeExceededException - if the size of this result exceeds the result size limit.

createSubResult

public QueryResult createSubResult()

Description copied from interface: Result

Creates a new empty sub result of the same type as this result.

This method is used by the query execution engine while constructing the partial sub results. These sub results are combined with this result during the final stage of the result construction.

Specified by:

createSubResult in interface Result<QueryResult>

Returns:

the created sub result.

orderAndLimit

public void orderAndLimit(PagingPredicate pagingPredicate,
                          Map.Entry<Integer,Map.Entry> nearestAnchorEntry)

Description copied from interface: Result

Performs the order-and-limit operation on this result for the given paging predicate.

Specified by:

orderAndLimit in interface Result<QueryResult>

Parameters:

pagingPredicate - the paging predicate to perform the operation for.

nearestAnchorEntry - the anchor entry of the paging predicate.

completeConstruction

public void completeConstruction(Collection<Integer> partitionIds)

Description copied from interface: Result

Completes the construction of this result.

Implementations may release intermediary resources associated with the construction in this method. No further modifications of the result are expected after this method invocation except combining the result with other results.

Specified by:

completeConstruction in interface Result<QueryResult>

Parameters:

partitionIds - the partition IDs to associate this result with.

See Also:

Result.combine(Result)

getPartitionIds

public Collection<Integer> getPartitionIds()

Specified by:

getPartitionIds in interface Result<QueryResult>

Returns:

partition IDs of this result.

combine

public void combine(QueryResult result)

Description copied from interface: Result

Combines the given result with this result modifying this result.

Specified by:

combine in interface Result<QueryResult>

Parameters:

result - the result to combine with.

See Also:

Result.onCombineFinished()

onCombineFinished

public void onCombineFinished()

Description copied from interface: Result

Invoked when the result combining phase is finished.

Implementations may release intermediary resources associated with the combining. No further calls to Result.combine(T) are expected after this method invocation.

Specified by:

onCombineFinished in interface Result<QueryResult>

See Also:

Result.combine(Result)

setPartitionIds

public void setPartitionIds(Collection<Integer> partitionIds)

Description copied from interface: Result

Sets the partition IDs of this result.

Specified by:

setPartitionIds in interface Result<QueryResult>

Parameters:

partitionIds - the partition IDs to set.

getRows

public List<QueryResultRow> getRows()

Returns:

the rows of this result.

getFactoryId

public int getFactoryId()

Description copied from interface: IdentifiedDataSerializable

Returns DataSerializableFactory factory ID for this class.

Specified by:

getFactoryId in interface IdentifiedDataSerializable

Returns:

factory ID

getId

public int getId()

Description copied from interface: IdentifiedDataSerializable

Returns type identifier for this class. It should be unique per DataSerializableFactory.

Specified by:

getId in interface IdentifiedDataSerializable

Returns:

type ID

writeData

public void writeData(ObjectDataOutput out)
               throws IOException

Description copied from interface: DataSerializable

Writes object fields to output stream

Specified by:

writeData in interface DataSerializable

Parameters:

out - output

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.

readData

public void readData(ObjectDataInput in)
              throws IOException

Description copied from interface: DataSerializable

Reads fields from the input stream

Specified by:

readData in interface DataSerializable

Parameters:

in - input

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.