DStreamToStreamAdapterFunctionTests.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,
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 * See the License for the specific language governing permissions and
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package io.dstream.function;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import org.junit.Test;

import io.dstream.SerializableStreamAssets.SerFunction;
import io.dstream.SerializableStreamAssets.SerPredicate;
import io.dstream.function.DStreamToStreamAdapterFunction;

public class DStreamToStreamAdapterFunctionTests {
	
	@Test(expected=IllegalArgumentException.class)
	public void unsupportedOperation(){
		new DStreamToStreamAdapterFunction("foo", (SerFunction<?,?>)s -> s);
	}
	
	@Test
	public void validateMap(){
		SerFunction<String, String> mapFunction = s -> s.toUpperCase();
		DStreamToStreamAdapterFunction f = new DStreamToStreamAdapterFunction("map", mapFunction);
		String result = (String) f.apply(Stream.of("foo")).findFirst().get();
		assertEquals("FOO", result);
	}
	
	@SuppressWarnings("unchecked")
	@Test
	public void validateflatMap(){
		SerFunction<String, Stream<String>> flatMapFunction = s -> Stream.of(s.split(" "));
		DStreamToStreamAdapterFunction f = new DStreamToStreamAdapterFunction("flatMap", flatMapFunction);	
		Stream<String> resultStream = (Stream<String>) f.apply(Stream.of("foo bar"));
		List<String> result = resultStream.collect(Collectors.toList());
		assertEquals("foo", result.get(0));
		assertEquals("bar", result.get(1));
	}
	
	@Test
	public void validateFilter(){
		SerPredicate<String> filterFunction = s -> s.equals("foo");
		DStreamToStreamAdapterFunction f = new DStreamToStreamAdapterFunction("filter", filterFunction);
		assertFalse(f.apply(Stream.of("bar")).findFirst().isPresent());
		assertTrue(f.apply(Stream.of("foo")).findFirst().isPresent());
	}
	
	@SuppressWarnings({ "unchecked", "rawtypes" })
	@Test
	public void validateSequence(){
		SerFunction<String, Stream<String>> flatMapFunction = s -> Stream.of(s.split(" "));
		DStreamToStreamAdapterFunction f0 = new DStreamToStreamAdapterFunction("flatMap", flatMapFunction);	
		
		SerPredicate<String> filterFunction = s -> s.equals("foo");
		DStreamToStreamAdapterFunction f1 = new DStreamToStreamAdapterFunction("filter", filterFunction);
		
		SerFunction<String, String> mapFunction = s -> s.toUpperCase();
		DStreamToStreamAdapterFunction f2 = new DStreamToStreamAdapterFunction("map", mapFunction);
		
		SerFunction f =  f0.andThen(f1).andThen(f2);
		assertEquals("FOO", ((Stream<String>)f.apply(Stream.of("foo bar"))).findFirst().get());
	}
}