Java List.parallelStream方法代碼示例

import java.util.List; //導入方法依賴的package包/類
public InternalContentProviderProxy<U> setTableEntries(List<RankedItem<U>> tableEntries) {
	// TODO optimize and only create a stream when necessary
	Stream<RankedItem<U>> tableStream = tableEntries.parallelStream();
	if (sortResolverFn != null) {
		tableStream = sortResolverFn.apply(tableStream);
	}
	
	tableStream = applyFilters(tableStream);
	
	this.tableEntries = tableStream.collect(Collectors.toList());
	return this;
}
 

import java.util.List; //導入方法依賴的package包/類
public static void main(String[] args) throws IOException {
	
	//Creating Streams using user/programmatically specified elements  
	 Stream<String> Userstream = Stream.of("Creating","Streams","from","Specific","elements");
	 Userstream.forEach(p -> System.out.println(p));
     
	 
	 //Creating Streams using array of objects
        Stream<String> ArrayStream = Stream.of( new String[]{"Stream","from","an","array","of","objects"} );
        ArrayStream.forEach(p -> System.out.println(p)); 
    
       
        //Creating Streams from an array
        String[] StringArray=new String[]{"We","can","convert","an","array","to","a","Stream","using","Arrays","as","well"};
        Stream<String> StringStream=Arrays.stream(StringArray);
        StringStream.forEach(p -> System.out.println(p));
        
        //Creating Streams from Collection
        List<Double> myCollection = new ArrayList<>();
        for(int i=0; i<10; i++){
       	 myCollection.add(Math.random());
        }
               //sequential stream
        Stream<Double> sequentialStream = myCollection.stream();
        sequentialStream.forEach(p -> System.out.println(p));
        		
                //parallel stream
        Stream<Double> parallelStream = myCollection.parallelStream();
        parallelStream.forEach(p -> System.out.println(p));
        
        
        //Stream from Hashmap
        Map<String, Integer> mapData = new HashMap<>();
        mapData.put("This", 1900);
        mapData.put("is", 2000);
        mapData.put("HashMap", 2100);
        
        mapData.entrySet()
       		.stream()
       		.forEach(p -> System.out.println(p));
        
        mapData.keySet()
               .stream()
               .forEach(p-> System.out.println(p));
        
        //primitive streams 
        IntStream.range(1, 4)
        .forEach(p -> System.out.println(p));
        
        LongStream.rangeClosed(1, 4)
        .forEach(p -> System.out.println(p));
        
        DoubleStream.of(1.0,2.0,3.0,4.0)
        .forEach(p -> System.out.println(p));
        
        //Infinite Streams using generate()
        Stream <Double> sequentialDoubleStream = Stream.generate(Math :: random); 

        Stream<Integer> sequentialIntegerStream = Stream.generate(new AtomicInteger () :: getAndIncrement); 

        //Infinite Streams using iterate()
        Stream <Integer> sequentialIntegerStream1 = Stream.iterate (Integer.MIN_VALUE, i -> i++); 

        Stream <BigInteger> sequentialBigIntegerStream = Stream.iterate(BigInteger.ZERO, i -> i.add (BigInteger.TEN)); 
        
        //Streams from File
        Stream<String> streamOfStrings = Files.lines(Paths.get("Apology_by_Plato.txt"));
        Stream<String> streamWithCharset = Files.lines(Paths.get("Apology_by_Plato.txt"), Charset.forName("UTF-8"));

      
}