/*
 * 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.jena.util.iterator;

/**
    Combines the actions of <code>Map</code> and <code>Filter</code>, mapping
    unacceptable objects to <code>null</code> and acceptable ones to their mapped
    value.
*/
public interface MapFilter<R,S>
    {
    /**
        a compiled filter and test - returns null if x is unacceptable, and
        the mapped value if x is acceptable; clearly useless if the mapping
        might deliver null. Tough.
    */
    public S accept( R x );
    }
