org.modeshape.jcr.query.process
Class QueryEngine

java.lang.Object
  org.modeshape.jcr.query.process.QueryEngine

Direct Known Subclasses:

LuceneQueryEngine

@ThreadSafe
public class QueryEngine
extends Object

A query engine that is able to execute formal queries expressed in the Graph API's Abstract Query Model.

Field Summary

protected Optimizer	optimizer
protected Planner	planner
protected Processor	processor

Constructor Summary

QueryEngine(Planner planner, Optimizer optimizer, Processor processor)
Create a new query engine given the planner, optimizer, processor, and schemata.

Method Summary

protected QueryResultColumns	determineQueryResultColumns(PlanNode optimizedPlan, PlanHints hints)
QueryResults	execute(QueryContext context, QueryCommand query) Execute the supplied query by planning, optimizing, and then processing it.

Methods inherited from class java.lang.Object

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

Field Detail

planner

protected final Planner planner

optimizer

protected final Optimizer optimizer

processor

protected final Processor processor

Constructor Detail

QueryEngine

public QueryEngine(Planner planner,
                   Optimizer optimizer,
                   Processor processor)

Create a new query engine given the planner, optimizer, processor, and schemata.

Parameters:

planner - the planner that should be used to generate canonical query plans for the queries; may be null if the CanonicalPlanner should be used

optimizer - the optimizer that should be used to optimize the canonical query plan; may be null if the RuleBasedOptimizer should be used

processor - the processor implementation that should be used to process the planned query and return the results

Throws:

IllegalArgumentException - if the processor reference is null

Method Detail

execute

public QueryResults execute(QueryContext context,
                            QueryCommand query)
                     throws QueryCancelledException,
                            RepositoryException

Execute the supplied query by planning, optimizing, and then processing it.

Parameters:

context - the context in which the query should be executed

query - the query that is to be executed

Returns:

the query results; never null

Throws:

IllegalArgumentException - if the context or query references are null

QueryCancelledException - if the query was cancelled

RepositoryException - if there was a problem executing the query

determineQueryResultColumns

protected QueryResultColumns determineQueryResultColumns(PlanNode optimizedPlan,
                                                         PlanHints hints)