src/java/org/apache/cassandra/cql3/functions/ScalarFunction.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.cassandra.cql3.functions;

import java.nio.ByteBuffer;
import java.util.List;

import org.apache.cassandra.exceptions.InvalidRequestException;

/**
 * Determines a single output value based on a single input value.
 */
public interface ScalarFunction extends Function
{
    public boolean isCalledOnNullInput();

    /**
     * Applies this function to the specified parameter.
     *
     * @param protocolVersion protocol version used for parameters and return value
     * @param parameters the input parameters
     * @return the result of applying this function to the parameter
     * @throws InvalidRequestException if this function cannot not be applied to the parameter
     */
    public ByteBuffer execute(int protocolVersion, List<ByteBuffer> parameters) throws InvalidRequestException;
}