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/*
 * Copyright 2015, The Querydsl Team (http://www.querydsl.com/team)
 *
 * Licensed 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 com.querydsl.core.group;

import com.querydsl.core.types.Expression;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;

/**
 * A group of rows. Group is build according to GroupDefinitions.
 *
 * @author sasa
 */
public interface Group {

  /**
   * Groups elements as an array
   *
   * @return elements as an array
   */
  Object[] toArray();

  /**
   * Returns the value of the given group.
   *
   * @param  Type of element in a single ResultSet row, i.e. type of {@code Expression}
   * @param  Target type of this group, e.g. {@code List}
   * @param coldef
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type
   * @return Value of given group definition in this group
   */
   R getGroup(GroupExpression coldef);

  /**
   * Returns the value of the given single valued expression. This is the first value of given
   * column within this group of the ResultSet.
   *
   * @param  Value type
   * @param expr Grouped expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. Set)
   * @return Value of given expression in this group
   */
   T getOne(Expression expr);

  /**
   * Returns a Set of values in this group.
   *
   * @param  Value type of Set
   * @param expr Grouped expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. List)
   * @return Set of values in this group
   */
   Set getSet(Expression expr);

  /**
   * Returns a SortedSet of values in this group.
   *
   * @param  Value type of Set
   * @param expr Grouped expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. List)
   * @return Set of values in this group
   */
   SortedSet getSortedSet(Expression expr);

  /**
   * Returns a List of values in this group.
   *
   * @param  Value type of List
   * @param expr Grouped expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. Set)
   * @return List of values in this group
   */
   List getList(Expression expr);

  /**
   * Returns a Map of values in this group
   *
   * @param  Key type of result Map
   * @param  Value type of result Map
   * @param key Key expression
   * @param value Value expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. List)
   * @return Map of values in this group
   */
   Map getMap(Expression key, Expression value);

  /**
   * Returns a SortedMap of values in this group
   *
   * @param  Key type of result Map
   * @param  Value type of result Map
   * @param key Key expression
   * @param value Value expression
   * @throws NoSuchElementException if group is undefined.
   * @throws ClassCastException if group is of different type (e.g. List)
   * @return Map of values in this group
   */
   SortedMap getSortedMap(Expression key, Expression value);
}