content: /*
   * 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.controller.utilities;
  
  import java.util.Collections;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.ambari.server.controller.internal.PropertyPredicateVisitor;
  import org.apache.ambari.server.controller.predicate.BasePredicate;
  import org.apache.ambari.server.controller.predicate.PredicateVisitor;
  import org.apache.ambari.server.controller.predicate.PredicateVisitorAcceptor;
  import org.apache.ambari.server.controller.spi.Predicate;
  
  /**
   *
   */
  public class PredicateHelper {
  
    public static Set<String> getPropertyIds(Predicate predicate) {
      if (predicate instanceof BasePredicate) {
        return ((BasePredicate) predicate).getPropertyIds();
      }
      return Collections.emptySet();
    }
  
    public static void visit(Predicate predicate, PredicateVisitor visitor) {
      if (predicate instanceof PredicateVisitorAcceptor) {
        ((PredicateVisitorAcceptor) predicate).accept(visitor);
      }
    }
  
    /**
     * Get a map of property values from a given predicate.
     *
     * @param predicate  the predicate
     *
     * @return the map of properties
     */
    public static Map<String, Object> getProperties(Predicate predicate) {
      if (predicate == null) {
        return Collections.emptyMap();
      }
      PropertyPredicateVisitor visitor = new PropertyPredicateVisitor();
      visit(predicate, visitor);
      return visitor.getProperties();
    }
  }
  