geode-core/src/main/java/org/apache/geode/cache/query/Struct.java

/*
 * 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.geode.cache.query;

import org.apache.geode.cache.query.types.StructType;

/**
 * An immutable and thread-safe data type used by the result of some <code>SELECT</code> queries. It
 * allows us to represent of "tuple" of values. It has a fixed number of "fields", each of which has
 * a name and a value. The names and types of these fields are described by a {@link StructType}.
 *
 * @see SelectResults
 *
 * @since GemFire 4.0
 */
public interface Struct {

  /**
   * Return the value associated with the given field name
   *
   * @param fieldName the String name of the field
   * @return the value associated with the specified field
   * @throws IllegalArgumentException If this struct does not have a field named fieldName
   *
   * @see StructType#getFieldIndex
   */
  Object get(String fieldName);

  /**
   * Get the values in this struct
   *
   * @return the array of values
   */
  Object[] getFieldValues();

  /**
   * Returns the <code>StructType</code> that describes the fields of this <code>Struct</code>.
   */
  StructType getStructType();
}