com.blazebit.persistence.spi.JpqlFunction Maven / Gradle / Ivy
/*
* Copyright 2014 - 2021 Blazebit.
*
* 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.blazebit.persistence.spi;
/**
* Interface for implementing a JPA custom function that renders dbms specific code.
*
* An instance of this interface needs to be registered to be able to use the function in queries.
*
* @author Christian Beikov
* @since 1.0.0
* @see EntityManagerFactoryIntegrator#registerFunctions(javax.persistence.EntityManagerFactory, java.util.Map)
*/
public interface JpqlFunction {
/**
* Returns true if the function has arguments, false otherwise.
*
* @return true if the function has arguments, false otherwise
*/
public boolean hasArguments();
/**
* Returns false if parentheses might be skipped if no arguments are given, true otherwise.
*
* @return false if parentheses might be skipped if no arguments are given, true otherwise
*/
public boolean hasParenthesesIfNoArguments();
/**
* Returns the return type of this function.
*
* The return type may be null, but beware that nesting this function into other expressions may then fail.
*
* @param firstArgumentType The type of the first argument
* @return the return type of this function, or null
*/
public Class getReturnType(Class firstArgumentType);
/**
* Renders the function into the given function render context.
*
* @param context The context into which the function should be rendered
*/
public void render(FunctionRenderContext context);
}