at.srfg.miner.clientlib

Interface Query

All Known Implementing Classes:

MultiProxyQuery, SingleProxyQuery

public interface Query

Interface for (incrementally) retrieving results from the Server. A Query is tied to exactly 1 pair of (ResultHandle, Execution).

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 nextResultBlock() as long as 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 nextResults() with this query.

Method Detail

reset

void reset()

Resets the query such that the internal result pointer offset is set to 0. Thus, the next invocation of hasNext() and 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.

setLimit

void setLimit(int limit)

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

Parameters:

limit - the query limit

getLimit

int getLimit()

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).

Returns:

the limit of this query

hasNext

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

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

Returns:

true if more results are available, false otherwise.

Throws:

at.srfg.miner.exception.MinerException

nextResultBlock

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

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 setLimit(int)) is smaller than the number of results that became available since the last invocation of nextResultBlock().

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

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

This is a convenience method that repeatedly invokes nextResultBlock() as long as 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!

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

String getResultName()

Gets the name of the underlying ResultHandle.

Returns:

the name of the ResultHandle

getResultSelector

String getResultSelector()

Gets the selector of the underlying ResultHandle.

Returns:

the selector