/*
* JBoss DNA (http://www.jboss.org/dna)
* 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.
*
* JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
* 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.
*
* JBoss DNA 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.jboss.dna.graph.query;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import net.jcip.annotations.Immutable;
import org.jboss.dna.common.collection.Problems;
import org.jboss.dna.common.collection.SimpleProblems;
import org.jboss.dna.common.util.CheckArg;
import org.jboss.dna.graph.query.model.BindVariableName;
import org.jboss.dna.graph.query.model.TypeSystem;
import org.jboss.dna.graph.query.plan.PlanHints;
import org.jboss.dna.graph.query.validate.Schemata;
/**
* An immutable context in which queries are to be executed. Each query context defines the information that is available during
* query execution.
*/
@Immutable
public class QueryContext {
private final TypeSystem typeSystem;
private final PlanHints hints;
private final Schemata schemata;
private final Problems problems;
private final Map<String, Object> variables;
/**
* Create a new context for query execution.
*
* @param schemata the schemata
* @param typeSystem the types system
* @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 values or schmata are null
*/
public QueryContext( Schemata schemata,
TypeSystem typeSystem,
PlanHints hints,
Problems problems,
Map<String, Object> variables ) {
CheckArg.isNotNull(typeSystem, "typeSystem");
CheckArg.isNotNull(schemata, "schemata");
this.typeSystem = typeSystem;
this.hints = hints != null ? hints : new PlanHints();
this.schemata = schemata;
this.problems = problems != null ? problems : new SimpleProblems();
this.variables = variables != null ? Collections.<String, Object>unmodifiableMap(new HashMap<String, Object>(variables)) : Collections.<String, Object>emptyMap();
assert this.typeSystem != null;
assert this.hints != null;
assert this.schemata != null;
assert this.problems != null;
assert this.variables != null;
}
/**
* Create a new context for query execution.
*
* @param schemata the schemata
* @param typeSystem the types system
* @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 values or schmata are null
*/
public QueryContext( Schemata schemata,
TypeSystem typeSystem,
PlanHints hints,
Problems problems ) {
this(schemata, typeSystem, hints, problems, null);
}
/**
* Create a new context for query execution.
*
* @param schemata the schemata
* @param typeSystem the types system
* @param hints the hints, or null if there are no hints
* @throws IllegalArgumentException if the context or schmata are null
*/
public QueryContext( Schemata schemata,
TypeSystem typeSystem,
PlanHints hints ) {
this(schemata, typeSystem, hints, null, null);
}
/**
* Create a new context for query execution.
*
* @param schemata the schemata
* @param typeSystem the types system
* @throws IllegalArgumentException if the values or schmata are null
*/
public QueryContext( Schemata schemata,
TypeSystem typeSystem ) {
this(schemata, typeSystem, 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.schemata, original.typeSystem, original.hints, original.problems, original.variables);
}
/**
* 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<String, Object> 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 type system.
*
* @param typeSystem the type system that should be used in the new query context
* @return the new context; never null
* @throws IllegalArgumentException if the execution context reference is null
*/
public QueryContext with( TypeSystem typeSystem ) {
CheckArg.isNotNull(typeSystem, "typeSystem");
return new QueryContext(schemata, typeSystem, hints, problems, variables);
}
/**
* 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(schemata, typeSystem, 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(schemata, typeSystem, 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(schemata, typeSystem, 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<String, Object> variables ) {
return new QueryContext(schemata, typeSystem, hints, problems, variables);
}
}