/*
 * 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.flink.test.streaming.runtime.util;

import org.apache.flink.api.common.functions.OpenContext;
import org.apache.flink.streaming.api.functions.sink.legacy.RichSinkFunction;

import java.util.ArrayList;
import java.util.List;

import static org.junit.Assert.assertTrue;

/**
 * SinkFunction asserting that at least one record was collected.
 *
 * @param <T> element type
 */
public final class ReceiveCheckNoOpSink<T> extends RichSinkFunction<T> {
    private List<T> received;

    public void invoke(T tuple) {
        received.add(tuple);
    }

    public void open(OpenContext openContext) {
        received = new ArrayList<T>();
    }

    public void close() {
        assertTrue(received.size() > 0);
    }
}
