at.srfg.miner.clientlib

Class MultiProxyQuery

Object

at.srfg.miner.clientlib.MultiProxyQuery

All Implemented Interfaces:

Query

public class MultiProxyQuery
extends Object
implements Query

This Query implementation handles the case where a ResultHandle is associated with potentially more than 1 ToolProxy. Internally, this class uses a SingleProxyQuery per ToolProxy that it has to query results from. On each invocation of Query.nextResults(), Query.nextResultBlock(), it gets the results from each ToolProxy and merges them into a single List<Result>.

Constructor Summary

Constructors

Constructor and Description
MultiProxyQuery(Execution exec, ResultHandle resultHandle) Constructs a new instance from an Execution and a ResultHandle.

Method Summary

Methods

Modifier and Type	Method and Description
int	getLimit() Gets the query limit of this query.
String	getResultName() Gets the name of the underlying ResultHandle.
String	getResultSelector() Gets the selector of the underlying ResultHandle.
boolean	hasNext() Checks if there are results that have not yet been retrieved.
List<Result>	nextResultBlock() Incrementally retrieves the next chunk of results.
List<Result>	nextResults() This is a convenience method that repeatedly invokes Query.nextResultBlock() as long as Query.hasNext() returns true.
void	reset() Resets the query such that the internal result pointer offset is set to 0.
void	setLimit(int limit) Sets a limit for the maximum number of result instances that are retrieved per invocation of Query.nextResults() with this query.

Methods inherited from class Object

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

Constructor Detail

MultiProxyQuery

public MultiProxyQuery(Execution exec,
               ResultHandle resultHandle)

Constructs a new instance from an Execution and a ResultHandle.

Parameters:

exec - the execution

resultHandle - the resultHandle

Throws:

IllegalArgumentException - if an input parameter is null.

Method Detail

reset

public void reset()

Description copied from interface: Query

Resets the query such that the internal result pointer offset is set to 0. Thus, the next invocation of Query.hasNext() and Query.nextResults() will return results starting from the very first one, not the next result since the last use of the Query. The limit and queryString are not affected by the reset.

Specified by:

reset in interface Query

setLimit

public void setLimit(int limit)

Description copied from interface: Query

Sets a limit for the maximum number of result instances that are retrieved per invocation of Query.nextResults() with this query.

Specified by:

setLimit in interface Query

Parameters:

limit - the query limit

getLimit

public int getLimit()

Description copied from interface: Query

Gets the query limit of this query. Note that this does not get the limit which my be imposed by the server (and which overrides any query limit by a client).

Specified by:

getLimit in interface Query

Returns:

the limit of this query

hasNext

public boolean hasNext()
                throws at.srfg.miner.exception.MinerException

Description copied from interface: Query

Checks if there are results that have not yet been retrieved.

Specified by:

hasNext in interface Query

Returns:

true if more results are available, false otherwise.

Throws:

at.srfg.miner.exception.MinerException

nextResultBlock

public List<Result> nextResultBlock()
                             throws at.srfg.miner.exception.MinerException

Description copied from interface: Query

Incrementally retrieves the next chunk of results. Note that there are possibly more results available than returned by the method. This can happen if the server imposed limit or the limit set by the user (see Query.setLimit(int)) is smaller than the number of results that became available since the last invocation of Query.nextResultBlock().

Specified by:

nextResultBlock in interface Query

Returns:

An unsorted list of new results, possibly limited by a local or server imposed limit. If there aren't any, an empty list is returned (but never null).

Throws:

at.srfg.miner.exception.MinerException

nextResults

public List<Result> nextResults()
                         throws at.srfg.miner.exception.MinerException

Description copied from interface: Query

This is a convenience method that repeatedly invokes Query.nextResultBlock() as long as Query.hasNext() returns true. It thus retrieves all results that became available since the last result query, even if the number is higher than a local or server imposed limit.

WARNING: if there are many new results at the server, this call may lead to a heap space problem!

Specified by:

nextResults in interface Query

Returns:

An unsorted list of all new results. If there aren't any, an empty list is returned (but never null).

Throws:

at.srfg.miner.exception.MinerException

getResultName

public String getResultName()

Description copied from interface: Query

Gets the name of the underlying ResultHandle.

Specified by:

getResultName in interface Query

Returns:

the name of the ResultHandle

getResultSelector

public String getResultSelector()

Description copied from interface: Query

Gets the selector of the underlying ResultHandle.

Specified by:

getResultSelector in interface Query

Returns:

the selector