ProjectionRole.java

/*
 * 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.types;

/**
 * Defines a custom projection for an {@link Expression} type. This interface can be used for Expressions which
 * behave in a different way when used as part of the projection.
 *
 * <p>Usually FactoryExpression instances are used as the custom projection.</p>
 *
 * @author tiwe
 * @param <T> expression type
 */
public interface ProjectionRole<T> {

    /**
     * Return the custom projection
     *
     * @return custom projection
     */
    Expression<T> getProjection();

}