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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.jackrabbit.oak.query;
import static com.google.common.collect.ImmutableSet.of;
import static org.apache.jackrabbit.JcrConstants.JCR_SYSTEM;
import static org.apache.jackrabbit.oak.plugins.nodetype.NodeTypeConstants.JCR_NODE_TYPES;
import java.text.ParseException;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.jackrabbit.oak.api.PropertyValue;
import org.apache.jackrabbit.oak.api.QueryEngine;
import org.apache.jackrabbit.oak.api.Result;
import org.apache.jackrabbit.oak.namepath.LocalNameMapper;
import org.apache.jackrabbit.oak.namepath.NamePathMapper;
import org.apache.jackrabbit.oak.namepath.NamePathMapperImpl;
import org.apache.jackrabbit.oak.query.xpath.XPathToSQL2Converter;
import org.apache.jackrabbit.oak.spi.state.NodeState;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
/**
* The query engine implementation.
*/
public abstract class QueryEngineImpl implements QueryEngine {
private static final AtomicInteger ID_COUNTER = new AtomicInteger();
private static final String MDC_QUERY_ID = "oak.query.id";
private static final String OAK_QUERY_ANALYZE = "oak.query.analyze";
static final String SQL2 = "JCR-SQL2";
static final String SQL = "sql";
static final String XPATH = "xpath";
static final String JQOM = "JCR-JQOM";
static final String NO_LITERALS = "-noLiterals";
static final Logger LOG = LoggerFactory.getLogger(QueryEngineImpl.class);
private static final Set SUPPORTED_LANGUAGES = of(
SQL2, SQL2 + NO_LITERALS,
SQL, SQL + NO_LITERALS,
XPATH, XPATH + NO_LITERALS,
JQOM);
/**
* Whether node traversal is enabled. This is enabled by default, and can be
* disabled for testing purposes.
*/
private boolean traversalEnabled = true;
/**
* @return Execution context for a single query execution.
*/
protected abstract ExecutionContext getExecutionContext();
@Override
public Set getSupportedQueryLanguages() {
return SUPPORTED_LANGUAGES;
}
/**
* Parse the query (check if it's valid) and get the list of bind variable names.
*
* @param statement query statement
* @param language query language
* @param mappings namespace prefix mappings
* @return the list of bind variable names
* @throws ParseException
*/
@Override
public List getBindVariableNames(
String statement, String language, Map mappings)
throws ParseException {
Query q = parseQuery(statement, language, getExecutionContext(), mappings);
return q.getBindVariableNames();
}
private static Query parseQuery(
String statement, String language, ExecutionContext context,
Map mappings) throws ParseException {
boolean isInternal = SQL2Parser.isInternal(statement);
if (isInternal) {
LOG.trace("Parsing {} statement: {}", language, statement);
} else {
LOG.debug("Parsing {} statement: {}", language, statement);
}
NamePathMapper mapper = new NamePathMapperImpl(
new LocalNameMapper(context.getRoot(), mappings));
NodeState types = context.getBaseState()
.getChildNode(JCR_SYSTEM)
.getChildNode(JCR_NODE_TYPES);
QueryEngineSettings settings = context.getSettings();
SQL2Parser parser = new SQL2Parser(mapper, types, settings);
if (language.endsWith(NO_LITERALS)) {
language = language.substring(0, language.length() - NO_LITERALS.length());
parser.setAllowNumberLiterals(false);
parser.setAllowTextLiterals(false);
}
if (SQL2.equals(language) || JQOM.equals(language)) {
return parser.parse(statement);
} else if (SQL.equals(language)) {
parser.setSupportSQL1(true);
return parser.parse(statement);
} else if (XPATH.equals(language)) {
XPathToSQL2Converter converter = new XPathToSQL2Converter();
String sql2 = converter.convert(statement);
LOG.debug("XPath > SQL2: {}", sql2);
try {
// OAK-874: No artificial XPath selector name in wildcards
parser.setIncludeSelectorNameInWildcardColumns(false);
return parser.parse(sql2);
} catch (ParseException e) {
ParseException e2 = new ParseException(
statement + " converted to SQL-2 " + e.getMessage(), 0);
e2.initCause(e);
throw e2;
}
} else {
throw new ParseException("Unsupported language: " + language, 0);
}
}
@Override
public Result executeQuery(
String statement, String language, long limit, long offset,
Map bindings,
Map mappings) throws ParseException {
if (limit < 0) {
throw new IllegalArgumentException("Limit may not be negative, is: " + limit);
}
if (offset < 0) {
throw new IllegalArgumentException("Offset may not be negative, is: " + offset);
}
// avoid having to deal with null arguments
if (bindings == null) {
bindings = NO_BINDINGS;
}
if (mappings == null) {
mappings = NO_MAPPINGS;
}
ExecutionContext context = getExecutionContext();
Query q = parseQuery(statement, language, context, mappings);
q.setExecutionContext(context);
q.setLimit(limit);
q.setOffset(offset);
if (bindings != null) {
for (Entry e : bindings.entrySet()) {
q.bindValue(e.getKey(), e.getValue());
}
}
q.setTraversalEnabled(traversalEnabled);
boolean mdc = false;
try {
mdc = setupMDC(q);
q.prepare();
return q.executeQuery();
} finally {
if (mdc) {
clearMDC();
}
}
}
protected void setTraversalEnabled(boolean traversalEnabled) {
this.traversalEnabled = traversalEnabled;
}
private static boolean setupMDC(Query q) {
boolean mdcEnabled = false;
if (q.isMeasureOrExplainEnabled()) {
MDC.put(OAK_QUERY_ANALYZE, Boolean.TRUE.toString());
mdcEnabled = true;
}
if (LOG.isDebugEnabled()) {
MDC.put(MDC_QUERY_ID, String.valueOf(ID_COUNTER.incrementAndGet()));
mdcEnabled = true;
}
return mdcEnabled;
}
private static void clearMDC() {
MDC.remove(MDC_QUERY_ID);
MDC.remove(OAK_QUERY_ANALYZE);
}
}
