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.jdbc;
  
  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;
  import org.apache.ambari.server.controller.utilities.PropertyHelper;
  
  /**
   * Predicate visitor used to generate a SQL where clause from a predicate graph.
   */
  public class SQLPredicateVisitor implements PredicateVisitor {
  
    /**
     * The string builder.
     */
    private final StringBuilder stringBuilder = new StringBuilder();
  
  
    // ----- PredicateVisitor --------------------------------------------------
  
    @Override
    public void acceptComparisonPredicate(ComparisonPredicate predicate) {
      String propertyId = predicate.getPropertyId();
  
      String propertyCategory = PropertyHelper.getPropertyCategory(propertyId);
      if (propertyCategory != null) {
        stringBuilder.append(propertyCategory).append(".");
      }
      stringBuilder.append(PropertyHelper.getPropertyName(propertyId));
  
      stringBuilder.append(" ").append(predicate.getOperator()).append(" \"");
      stringBuilder.append(predicate.getValue());
      stringBuilder.append("\"");
  
    }
  
    @Override
    public void acceptArrayPredicate(ArrayPredicate predicate) {
      Predicate[] predicates = predicate.getPredicates();
      if (predicates.length > 0) {
  
        stringBuilder.append("(");
        for (int i = 0; i < predicates.length; i++) {
          if (i > 0) {
            stringBuilder.append(" ").append(predicate.getOperator()).append(" ");
          }
          PredicateHelper.visit(predicates[i], this);
        }
        stringBuilder.append(")");
      }
    }
  
    @Override
    public void acceptUnaryPredicate(UnaryPredicate predicate) {
      stringBuilder.append(predicate.getOperator()).append("(");
      PredicateHelper.visit(predicate.getPredicate(), this);
      stringBuilder.append(")");
    }
  
    @Override
    public void acceptAlwaysPredicate(AlwaysPredicate predicate) {
      stringBuilder.append("TRUE");
    }
  
    @Override
    public void acceptCategoryPredicate(CategoryPredicate predicate) {
      // Do nothing
    }
  
  
    // ----- SQLPredicateVisitor -----------------------------------------------
  
    public String getSQL() {
      return stringBuilder.toString();
    }
  }
  