/**
* 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.ambari.server.api.query;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.ambari.server.controller.predicate.AlwaysPredicate;
import org.apache.ambari.server.controller.predicate.ArrayPredicate;
import org.apache.ambari.server.controller.predicate.CategoryPredicate;
import org.apache.ambari.server.controller.predicate.ComparisonPredicate;
import org.apache.ambari.server.controller.predicate.PredicateVisitor;
import org.apache.ambari.server.controller.predicate.UnaryPredicate;
import org.apache.ambari.server.controller.spi.Predicate;
import org.apache.ambari.server.controller.utilities.PredicateHelper;
/**
* A predicate visitor used to process a predicate to do the following :
*
* 1) Create a new predicate with all sub-resource elements contained in the
* visited predicate removed (converted to AlwaysPredicate).
* 2) Create a set of any sub-resource subResourceCategories that were referenced in
* the predicate being visited (i.e. components, host_components, etc).
* 3) Create a set of any sub-resource subResourceProperties that were referenced in
* the predicate being visited.
*
* For example, the service level query the predicate ...
*
* ServiceInfo/service_name = HBASE AND
* components/ServiceComponentInfo/category = SLAVE AND
* components/host_components/metrics/cpu/cpu_num >= 1
*
* ... will produce ...
*
* Predicate : ServiceInfo/service_name = HBASE
*
* Sub-resource subResourceCategories : {components}
*
* Sub-resource subResourceProperties : {components/ServiceComponentInfo/category,
* components/host_components/metrics/cpu/cpu_num}
*/
public class ProcessingPredicateVisitor implements PredicateVisitor {
/**
* Associated resource provider.
*/
private final QueryImpl query;
/**
* The last visited predicate.
*/
private Predicate lastVisited = null;
/**
* The set of sub-resource categories.
*/
private final Set<String> subResourceCategories = new HashSet<>();
/**
* The set of sub-resource properties.
*/
private final Set<String> subResourceProperties = new HashSet<>();
// ----- Constructors ----------------------------------------------------
/**
* Constructor.
*
* @param query associated query
*/
public ProcessingPredicateVisitor(QueryImpl query) {
this.query = query;
}
// ----- PredicateVisitor --------------------------------------------------
@Override
public void acceptComparisonPredicate(ComparisonPredicate predicate) {
String propertyId = predicate.getPropertyId();
int index = propertyId.indexOf("/");
String category = index == -1 ? propertyId : propertyId.substring(0, index);
Map<String, QueryImpl> subResources = query.ensureSubResources();
if (subResources.containsKey(category)) {
subResourceCategories.add(category);
subResourceProperties.add(propertyId);
lastVisited = AlwaysPredicate.INSTANCE;
}
else {
lastVisited = predicate;
}
}
@Override
public void acceptArrayPredicate(ArrayPredicate arrayPredicate) {
List<Predicate> predicateList = new LinkedList<>();
Predicate[] predicates = arrayPredicate.getPredicates();
if (predicates.length > 0) {
for (Predicate predicate : predicates) {
PredicateHelper.visit(predicate, this);
predicateList.add(lastVisited);
}
}
lastVisited = arrayPredicate.create(predicateList.toArray(new Predicate[predicateList.size()]));
}
@Override
public void acceptUnaryPredicate(UnaryPredicate predicate) {
String propertyId = predicate.getPropertyIds().iterator().next();
int index = propertyId.indexOf("/");
String category = index == -1 ? propertyId : propertyId.substring(0, index);
Map<String, QueryImpl> subResources = query.ensureSubResources();
if (subResources.containsKey(category)) {
subResourceCategories.add(category);
subResourceProperties.add(propertyId);
lastVisited = AlwaysPredicate.INSTANCE;
}
else {
lastVisited = predicate;
}
}
@Override
public void acceptAlwaysPredicate(AlwaysPredicate predicate) {
lastVisited = predicate;
}
@Override
public void acceptCategoryPredicate(CategoryPredicate predicate) {
lastVisited = predicate;
}
// ----- utility methods -------------------------------------------------
/**
* Get a new predicate with all sub-resource elements contained in the
* visited predicate removed.
*
* @return the new predicate
*/
public Predicate getProcessedPredicate() {
return lastVisited;
}
/**
* Get a set of any sub-resource subResourceCategories that were referenced
* in the predicate that was visited.
*
* @return the set of sub-resource categories
*/
public Set<String> getSubResourceCategories() {
return subResourceCategories;
}
/**
* Get a set of any sub-resource subResourceProperties that were referenced
* in the predicate that was visited.
*
* @return the set of sub-resource properties
*/
public Set<String> getSubResourceProperties() {
return subResourceProperties;
}
}