org.modeshape.jcr.query.QueryContext Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
* See the AUTHORS.txt file in the distribution for a full listing of
* individual contributors.
*
* ModeShape is free software. Unless otherwise indicated, all code in ModeShape
* is licensed to you under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* ModeShape is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.modeshape.jcr.query;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import org.modeshape.common.annotation.ThreadSafe;
import org.modeshape.common.collection.Problems;
import org.modeshape.common.collection.SimpleProblems;
import org.modeshape.common.util.CheckArg;
import org.modeshape.jcr.ExecutionContext;
import org.modeshape.jcr.cache.NodeCache;
import org.modeshape.jcr.cache.RepositoryCache;
import org.modeshape.jcr.cache.WorkspaceNotFoundException;
import org.modeshape.jcr.query.model.BindVariableName;
import org.modeshape.jcr.query.model.TypeSystem;
import org.modeshape.jcr.query.plan.PlanHints;
import org.modeshape.jcr.query.validate.Schemata;
import org.modeshape.jcr.value.NamespaceRegistry;
/**
* An immutable context in which queries are to be executed. Each query context defines the information that is available during
* query execution.
*
* The only mutable state on this context is whether the query has been {@link #cancel() cancelled}.
*
*/
@ThreadSafe
public class QueryContext {
private final ExecutionContext context;
private final RepositoryCache repositoryCache;
private final TypeSystem typeSystem;
private final PlanHints hints;
private final Schemata schemata;
private final Problems problems;
private final Map variables;
private final Set workspaceNames;
private final Map overriddenNodeCachesByWorkspaceName;
private final AtomicBoolean cancelled = new AtomicBoolean(false);
/**
* Create a new context for query execution.
*
* @param context the context in which the query is being executed; may not be null
* @param repositoryCache the repository cache that should be used to load results; may be null if no results are to be loaded
* @param workspaceNames the name of each workspace to be queried, or an empty set if all the workspaces should be queried;
* may not be null
* @param overriddenNodeCachesByWorkspaceName the NodeCache instances that should be used to load results, which will be used
* instead of the RepositoryCache's NodeCache for a given workspace name; may be null or empty
* @param schemata the schemata
* @param hints the hints, or null if there are no hints
* @param problems the problems container, or null if a new problems container should be created
* @param variables the mapping of variables and values, or null if there are no such variables
* @throws IllegalArgumentException if the context, workspace name, or schemata are null
*/
public QueryContext( ExecutionContext context,
RepositoryCache repositoryCache,
Set workspaceNames,
Map overriddenNodeCachesByWorkspaceName,
Schemata schemata,
PlanHints hints,
Problems problems,
Map variables ) {
CheckArg.isNotNull(context, "context");
CheckArg.isNotNull(workspaceNames, "workspaceNames");
CheckArg.isNotNull(schemata, "schemata");
this.context = context;
this.repositoryCache = repositoryCache;
this.workspaceNames = workspaceNames;
this.typeSystem = context.getValueFactories().getTypeSystem();
this.hints = hints != null ? hints : new PlanHints();
this.schemata = schemata;
this.problems = problems != null ? problems : new SimpleProblems();
this.variables = variables != null ? new HashMap(variables) : new HashMap();
this.overriddenNodeCachesByWorkspaceName = overriddenNodeCachesByWorkspaceName != null ? overriddenNodeCachesByWorkspaceName : Collections.emptyMap();
assert this.typeSystem != null;
assert this.hints != null;
assert this.schemata != null;
assert this.problems != null;
assert this.variables != null;
assert this.workspaceNames != null;
}
/**
* Create a new context for query execution.
*
* @param context the context in which the query is being executed; may not be null
* @param repositoryCache the repository cache that should be used to load results; may not be null
* @param workspaceNames the name of each workspace to be queried, or an empty set if all the workspaces should be queried;
* may not be null
* @param schemata the schemata
* @param hints the hints, or null if there are no hints
* @param problems the problems container, or null if a new problems container should be created
* @throws IllegalArgumentException if the context, workspace name, or schemata are null
*/
public QueryContext( ExecutionContext context,
RepositoryCache repositoryCache,
Set workspaceNames,
Schemata schemata,
PlanHints hints,
Problems problems ) {
this(context, repositoryCache, workspaceNames, null, schemata, hints, problems, null);
}
/**
* Create a new context for query execution.
*
* @param context the context in which the query is being executed; may not be null
* @param repositoryCache the repository cache that should be used to load results; may not be null
* @param workspaceNames the name of each workspace to be queried, or an empty set if all the workspaces should be queried;
* may not be null
* @param schemata the schemata
* @throws IllegalArgumentException if the context, workspace name, or schemata are null
*/
public QueryContext( ExecutionContext context,
RepositoryCache repositoryCache,
Set workspaceNames,
Schemata schemata ) {
this(context, repositoryCache, workspaceNames, null, schemata, null, null, null);
}
/**
* Create a new context that is a copy of the supplied context. This constructor is useful for subclasses that wish to add
* store additional fields in a QueryContext.
*
* @param original the original context
* @throws IllegalArgumentException if the original is null
*/
protected QueryContext( QueryContext original ) {
this(original.context, original.repositoryCache, original.workspaceNames, original.overriddenNodeCachesByWorkspaceName,
original.schemata, original.hints, original.problems, original.variables);
}
/**
* Cancel the query if it is currently running. Note that this method does not block until the query is cancelled; it merely
* marks the query as being cancelled, and the query will terminate at its next available opportunity.
*
* @return true if the query was executing and will be cancelled, or false if the query was no longer running (because it had
* finished successfully or had already been cancelled) and could not be cancelled.
*/
public final boolean cancel() {
return this.cancelled.compareAndSet(false, true);
}
public final boolean isCancelled() {
return this.cancelled.get();
}
/**
* Get the NodeCache for the given workspace name. The result will either be the overridden value supplied in the constructor
* or the workspace cache from the referenced RepositoryCache.
*
* @param workspaceName the name of the workspace
* @return the node cache; never null
* @throws WorkspaceNotFoundException if there is no workspace with the supplied name
*/
public NodeCache getNodeCache( String workspaceName ) throws WorkspaceNotFoundException {
NodeCache cache = overriddenNodeCachesByWorkspaceName.get(workspaceName);
if (cache == null) {
cache = repositoryCache.getWorkspaceCache(workspaceName);
}
return cache;
}
/**
* Get the namespace registry with durable prefixes as used by the query indexes.
*
* @return the durable namespace registry; never null
*/
public NamespaceRegistry getNamespaceRegistry() {
// TODO: Durable namespace registry
return context.getNamespaceRegistry();
}
/**
* Get the RepositoryCache instance that should be used to load the result tuple values.
*
* @return the node cache
*/
public RepositoryCache getRepositoryCache() {
return repositoryCache;
}
/**
* Get the execution context in which the query is to be evaluated
*
* @return the execution context; never null
*/
public ExecutionContext getExecutionContext() {
return context;
}
/**
* Get the names of each workspace that is to be queried.
*
* @return the workspace name; never null
*/
public Set getWorkspaceNames() {
return workspaceNames;
}
/**
* Get the interface for working with literal values and types.
*
* @return the type system; never null
*/
public TypeSystem getTypeSystem() {
return typeSystem;
}
/**
* Get the plan hints.
*
* @return the plan hints; never null
*/
public final PlanHints getHints() {
return hints;
}
/**
* Get the problem container used by this query context. Any problems that have been encountered will be accumlated in this
* container.
*
* @return the problem container; never null
*/
public final Problems getProblems() {
return problems;
}
/**
* Get the definition of the tables available within this query context.
*
* @return the schemata; never null
*/
public Schemata getSchemata() {
return schemata;
}
/**
* Get the variables that are to be substituted into the {@link BindVariableName} used in the query.
*
* @return immutable map of variable values keyed by their name; never null but possibly empty
*/
public Map getVariables() {
return variables;
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( Object obj ) {
if (obj == this) return true;
if (obj instanceof QueryContext) {
QueryContext that = (QueryContext)obj;
if (!this.typeSystem.equals(that.getTypeSystem())) return false;
if (!this.schemata.equals(that.getSchemata())) return false;
if (!this.variables.equals(that.getVariables())) return false;
return true;
}
return false;
}
/**
* Obtain a copy of this context, except that the copy uses the supplied schemata.
*
* @param schemata the schemata that should be used in the new context
* @return the new context; never null
* @throws IllegalArgumentException if the schemata reference is null
*/
public QueryContext with( Schemata schemata ) {
CheckArg.isNotNull(schemata, "schemata");
return new QueryContext(context, repositoryCache, workspaceNames, overriddenNodeCachesByWorkspaceName, schemata, hints,
problems, variables);
}
/**
* Obtain a copy of this context, except that the copy uses the supplied hints.
*
* @param hints the hints that should be used in the new context
* @return the new context; never null
* @throws IllegalArgumentException if the hints reference is null
*/
public QueryContext with( PlanHints hints ) {
CheckArg.isNotNull(hints, "hints");
return new QueryContext(context, repositoryCache, workspaceNames, overriddenNodeCachesByWorkspaceName, schemata, hints,
problems, variables);
}
/**
* Obtain a copy of this context, except that the copy uses the supplied problem container.
*
* @param problems the problems that should be used in the new context; may be null if a new problem container should be used
* @return the new context; never null
*/
public QueryContext with( Problems problems ) {
return new QueryContext(context, repositoryCache, workspaceNames, overriddenNodeCachesByWorkspaceName, schemata, hints,
problems, variables);
}
/**
* Obtain a copy of this context, except that the copy uses the supplied variables.
*
* @param variables the variables that should be used in the new context; may be null if there are no such variables
* @return the new context; never null
*/
public QueryContext with( Map variables ) {
return new QueryContext(context, repositoryCache, workspaceNames, overriddenNodeCachesByWorkspaceName, schemata, hints,
problems, variables);
}
}
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