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.api.predicate.expressions;
  
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.ambari.server.api.predicate.InvalidQueryException;
  import org.apache.ambari.server.api.predicate.operators.LogicalOperator;
  import org.apache.ambari.server.controller.spi.Predicate;
  
  /**
   * Logical expression implementation.
   * Always a binary expression that consists of a logical operator and
   * expressions for the left and right operands.
   */
  public class LogicalExpression extends AbstractExpression<Expression> {
  
    /**
     * Constructor.
     *
     * @param op  the logical operator of the expression
     */
    public LogicalExpression(LogicalOperator op) {
      super(op);
    }
  
  
    @Override
    public Predicate toPredicate() throws InvalidQueryException {
      return ((LogicalOperator) getOperator()).
          toPredicate(getLeftOperand().toPredicate(), getRightOperand().toPredicate());
    }
  
    @Override
    public List<Expression> merge(Expression left, Expression right, int precedence) {
      if (getOperator().getPrecedence() == precedence && getLeftOperand() == null) {
        setLeftOperand(left);
        setRightOperand(right);
        return Collections.singletonList(this);
      } else {
        return defaultMerge(left, right);
      }
    }
  }
  