org.modeshape.jcr.query.JcrQuery Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.modeshape.jcr.query;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import javax.jcr.RepositoryException;
import javax.jcr.Value;
import javax.jcr.query.Query;
import org.modeshape.common.annotation.NotThreadSafe;
import org.modeshape.common.util.CheckArg;
import org.modeshape.common.util.StringUtil;
import org.modeshape.jcr.JcrI18n;
import org.modeshape.jcr.query.model.BindVariableName;
import org.modeshape.jcr.query.model.LiteralValue;
import org.modeshape.jcr.query.model.QueryCommand;
import org.modeshape.jcr.query.model.Subquery;
import org.modeshape.jcr.query.model.Visitors;
import org.modeshape.jcr.query.parse.QueryParser;
import org.modeshape.jcr.query.plan.PlanHints;
import org.modeshape.jcr.value.Path;
/**
* Implementation of {@link Query} that represents a {@link QueryCommand query command}.
*/
@NotThreadSafe
public class JcrQuery extends JcrAbstractQuery {
private QueryCommand query;
private final PlanHints hints;
private final Map variables;
private volatile Set variableNames;
private final AtomicReference executingQuery = new AtomicReference();
/**
* Creates a new JCR {@link Query} by specifying the query statement itself, the language in which the query is stated, the
* {@link QueryCommand} representation and, optionally, the node from which the query was loaded. The language must be a
* string from among those returned by {@code QueryManager#getSupportedQueryLanguages()}.
*
* @param context the context that was used to create this query and that will be used to execute this query; may not be null
* @param statement the original statement as supplied by the client; may not be null
* @param language the language obtained from the {@link QueryParser}; may not be null
* @param query the parsed query representation; may not be null
* @param hints any hints that are to be used; may be null if there are no hints
* @param storedAtPath the path at which this query was stored, or null if this is not a stored query
*/
public JcrQuery( JcrQueryContext context,
String statement,
String language,
QueryCommand query,
PlanHints hints,
Path storedAtPath ) {
super(context, statement, language, storedAtPath);
assert query != null;
this.query = query;
this.hints = hints;
this.variables = new HashMap();
}
@Override
public void includeSystemContent( boolean includeSystemContent ) {
this.hints.includeSystemContent = includeSystemContent;
}
protected QueryCommand query() {
return query;
}
/**
* Get the underlying and immutable Abstract Query Model representation of this query.
*
* @return the AQM representation; never null
*/
public QueryCommand getAbstractQueryModel() {
return query;
}
@Override
public String getAbstractQueryModelRepresentation() {
return query.toString();
}
/**
* {@inheritDoc}
*
* @see javax.jcr.query.Query#execute()
*/
@SuppressWarnings( "deprecation" )
@Override
public org.modeshape.jcr.api.query.QueryResult execute() throws RepositoryException {
context.checkValid();
final long start = System.nanoTime();
// Create an executable query and set it on this object ...
CancellableQuery newExecutable = context.createExecutableQuery(query, hints, variables);
CancellableQuery executable = executingQuery.getAndSet(newExecutable);
if (executable == null) {
// We are the first to call 'execute()', so use our newly-created one ...
executable = newExecutable;
}
// otherwise, some other thread called execute, so we can use it and just wait for the results ...
final QueryResults result = executable.execute(); // may be cancelled
// And reset the reference to null (if not already set to something else) ...
executingQuery.compareAndSet(executable, null);
checkForProblems(result.getProblems());
context.recordDuration(Math.abs(System.nanoTime() - start), TimeUnit.NANOSECONDS, statement, language);
if (Query.XPATH.equals(language)) {
return new XPathQueryResult(context, statement, result, hints.restartable, hints.rowsKeptInMemory);
} else if (Query.SQL.equals(language)) {
return new JcrSqlQueryResult(context, statement, result, hints.restartable, hints.rowsKeptInMemory);
}
return new JcrQueryResult(context, statement, result, hints.restartable, hints.rowsKeptInMemory);
}
@SuppressWarnings( "deprecation" )
@Override
public org.modeshape.jcr.api.query.QueryResult explain() throws RepositoryException {
context.checkValid();
// Set to only compute the plan and then create an executable query ...
PlanHints hints = this.hints.clone();
hints.planOnly = true;
CancellableQuery planOnlyExecutable = context.createExecutableQuery(query, hints, variables);
// otherwise, some other thread called execute, so we can use it and just wait for the results ...
final QueryResults result = planOnlyExecutable.execute(); // may be cancelled
checkForProblems(result.getProblems());
if (Query.XPATH.equals(language)) {
return new XPathQueryResult(context, statement, result, false, 0);
} else if (Query.SQL.equals(language)) {
return new JcrSqlQueryResult(context, statement, result, false, 0);
}
return new JcrQueryResult(context, statement, result, false, 0);
}
@Override
public boolean cancel() {
CancellableQuery executing = executingQuery.get();
if (executing != null) {
boolean cancelled = executing.cancel();
// Remove the reference (if still there as we obtained it several lines up) ...
executingQuery.compareAndSet(executing, null);
return cancelled;
}
return false;
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
return language + " -> " + statement + "\n" + StringUtil.createString(' ', Math.min(language.length() - 3, 0))
+ "AQM -> " + query;
}
@Override
public void bindValue( String varName,
Value value ) throws IllegalArgumentException, RepositoryException {
CheckArg.isNotNull(varName, "varName");
CheckArg.isNotNull(value, "value");
if (!variableNames().contains(varName) && !Subquery.isSubqueryVariableName(varName)) {
throw new IllegalArgumentException(JcrI18n.noSuchVariableInQuery.text(varName, statement));
}
variables.put(varName, LiteralValue.rawValue(value));
}
@Override
public String[] getBindVariableNames() {
Set names = variableNames();
// Always return a new array for immutability reasons ...
return names.toArray(new String[names.size()]);
}
protected final Set variableNames() {
// This is idempotent, so no need to lock ...
if (variableNames == null) {
// Walk the query to find the bind variables ...
final Set names = new HashSet();
Visitors.visitAll(query, new Visitors.AbstractVisitor() {
@Override
public void visit( BindVariableName obj ) {
names.add(obj.getBindVariableName());
}
});
variableNames = names;
}
return variableNames;
}
@Override
public void setLimit( long limit ) {
if (limit > Integer.MAX_VALUE) limit = Integer.MAX_VALUE;
query = query.withLimit((int)limit); // may not actually change if the limit matches the existing query
}
@Override
public void setOffset( long offset ) {
if (offset > Integer.MAX_VALUE) offset = Integer.MAX_VALUE;
query = query.withOffset((int)offset); // may not actually change if the offset matches the existing query
}
}
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