/*

  * #%L

  * MapStage2.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * 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.

  * #L%

  */

 package com.allanbank.mongodb.builder.expression;

 /**

  * MapStage2 provides a container for the {@code $map} input field name and

  * {@code as} variable name before adding the expression.

  * 

  * @api.yes This class is part of the driver's API. Public and protected members

  *          will be deprecated for at least 1 non-bugfix release (version

  *          numbers are <major>.<minor>.<bugfix>) before being

  *          removed or modified.

  * @copyright 2014, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class MapStage2 {

     /** The name of the {@code input} field. */

     private final String myInputField;

     /** The name of the {@code as} variable. */

     private final String myVariableName;

     /**

      * Creates a new MapStage2.

      * 

      * @param inputField

      *            The name of the {@code input} field.

      * @param variableName

      *            The name of the {@code as} variable.

      */

     /* package */MapStage2(final String inputField, final String variableName) {

         myInputField = inputField;

         myVariableName = variableName;

     }

     /**

      * Creates the final {@code $map} expression to evaluate.

      * 

      * @param mapOperation

      *            The expression to be evaluated with the variables within the

      *            {@code $map} expression.

      * @return The {@link UnaryExpression} for the {@code $map}.

      */

     public Expression in(final Expression mapOperation) {

         return Expressions.map(myInputField, myVariableName, mapOperation);

     }

 }