Java Code Examples for java.util.stream.Stream#generate()

The following examples show how to use java.util.stream.Stream#generate() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: TableDisplayStreamMapModelTest.java    From beakerx with Apache License 2.0 6 votes vote down vote up 
@NotNull
private Stream<Map<String, Object>> generateInfiniteStream() {
  return Stream.generate(new Supplier<Map<String, Object>>() {
    Random random = new Random();
    int index = 0;
    @Override
    public Map<String, Object> get() {
      return new LinkedHashMap<String, Object>() {
        {
          put("str1", index++);
          put("str2", random.nextFloat());
          put("str3", random.nextInt());
        }
      };
    }
  });
}
Example 2
Source File: DataStreamGeneratorTest.java    From ignite with Apache License 2.0 6 votes vote down vote up 
/** */
@Test
public void testAsMap() {
    DataStreamGenerator generator = new DataStreamGenerator() {
        @Override public Stream<LabeledVector<Double>> labeled() {
            return Stream.generate(() -> new LabeledVector<>(VectorUtils.of(1., 2.), 100.));
        }
    };

    int N = 100;
    Map<Vector, Double> dataset = generator.asMap(N);
    assertEquals(N, dataset.size());
    dataset.forEach(((vector, label) -> {
        assertArrayEquals(new double[] {1., 2.}, vector.asArray(), 1e-7);
        assertEquals(100., label, 1e-7);
    }));
}
Example 3
Source File: StreamFlagsTest.java    From openjdk-jdk8u-backup with GNU General Public License v2.0 5 votes vote down vote up 
public void testBaseStreams() {
    Stream<String> arrayList = new ArrayList<String>().stream();
    Stream<String> linkedList = new LinkedList<String>().stream();
    Stream<String> hashSet = new HashSet<String>().stream();
    Stream<String> treeSet = new TreeSet<String>().stream();
    Stream<String> linkedHashSet = new LinkedHashSet<String>().stream();
    Stream<String> repeat = Stream.generate(() -> "");

    assertFlags(OpTestCase.getStreamFlags(arrayList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(hashSet),
                EnumSet.of(SIZED, DISTINCT),
                EnumSet.of(ORDERED, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(treeSet),
                EnumSet.of(ORDERED, SIZED, DISTINCT, SORTED),
                EnumSet.of(SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedHashSet),
                EnumSet.of(ORDERED, DISTINCT, SIZED),
                EnumSet.of(SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(repeat),
                EnumSet.noneOf(StreamOpFlag.class),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
}
Example 4
Source File: DataStreamGeneratorTest.java    From ignite with Apache License 2.0 5 votes vote down vote up 
/** */
@Test
public void testAsDatasetBuilder() throws Exception {
    AtomicInteger cntr = new AtomicInteger();

    DataStreamGenerator generator = new DataStreamGenerator() {
        @Override public Stream<LabeledVector<Double>> labeled() {
            return Stream.generate(() -> {
                int val = cntr.getAndIncrement();
                return new LabeledVector<>(VectorUtils.of(val), (double)val % 2);
            });
        }
    };

    int N = 100;
    cntr.set(0);
    DatasetBuilder<Vector, Double> b1 = generator.asDatasetBuilder(N, 2);
    cntr.set(0);
    DatasetBuilder<Vector, Double> b2 = generator.asDatasetBuilder(N, (v, l) -> l == 0, 2);
    cntr.set(0);
    DatasetBuilder<Vector, Double> b3 = generator.asDatasetBuilder(N, (v, l) -> l == 1, 2,
        new UpstreamTransformerBuilder() {
            @Override public UpstreamTransformer build(LearningEnvironment env) {
                return new UpstreamTransformerForTest();
            }
        });

    checkDataset(N, b1, v -> (Double)v.label() == 0 || (Double)v.label() == 1);
    checkDataset(N / 2, b2, v -> (Double)v.label() == 0);
    checkDataset(N / 2, b3, v -> (Double)v.label() < 0);
}
Example 5
Source File: DataStreamGeneratorTest.java    From ignite with Apache License 2.0 5 votes vote down vote up 
/** */
@Test
public void testUnlabeled() {
    DataStreamGenerator generator = new DataStreamGenerator() {
        @Override public Stream<LabeledVector<Double>> labeled() {
            return Stream.generate(() -> new LabeledVector<>(VectorUtils.of(1., 2.), 100.));
        }
    };

    generator.unlabeled().limit(100).forEach(v -> assertArrayEquals(new double[] {1., 2.}, v.asArray(), 1e-7));
}
Example 6
Source File: ClientServerTest.java    From monsoon with BSD 3-Clause "New" or "Revised" License 5 votes vote down vote up 
private static Stream<Integer> generate() {
    class Generator implements Supplier<Integer> {
        private int i;

        @Override
        public Integer get() {
            return i++;
        }
    }

    return Stream.generate(new Generator());
}
Example 7
Source File: StreamFlagsTest.java    From openjdk-8-source with GNU General Public License v2.0 5 votes vote down vote up 
public void testBaseStreams() {
    Stream<String> arrayList = new ArrayList<String>().stream();
    Stream<String> linkedList = new LinkedList<String>().stream();
    Stream<String> hashSet = new HashSet<String>().stream();
    Stream<String> treeSet = new TreeSet<String>().stream();
    Stream<String> linkedHashSet = new LinkedHashSet<String>().stream();
    Stream<String> repeat = Stream.generate(() -> "");

    assertFlags(OpTestCase.getStreamFlags(arrayList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(hashSet),
                EnumSet.of(SIZED, DISTINCT),
                EnumSet.of(ORDERED, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(treeSet),
                EnumSet.of(ORDERED, SIZED, DISTINCT, SORTED),
                EnumSet.of(SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedHashSet),
                EnumSet.of(ORDERED, DISTINCT, SIZED),
                EnumSet.of(SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(repeat),
                EnumSet.noneOf(StreamOpFlag.class),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
}
Example 8
Source File: StreamFlagsTest.java    From hottub with GNU General Public License v2.0 5 votes vote down vote up 
public void testBaseStreams() {
    Stream<String> arrayList = new ArrayList<String>().stream();
    Stream<String> linkedList = new LinkedList<String>().stream();
    Stream<String> hashSet = new HashSet<String>().stream();
    Stream<String> treeSet = new TreeSet<String>().stream();
    Stream<String> linkedHashSet = new LinkedHashSet<String>().stream();
    Stream<String> repeat = Stream.generate(() -> "");

    assertFlags(OpTestCase.getStreamFlags(arrayList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(hashSet),
                EnumSet.of(SIZED, DISTINCT),
                EnumSet.of(ORDERED, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(treeSet),
                EnumSet.of(ORDERED, SIZED, DISTINCT, SORTED),
                EnumSet.of(SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedHashSet),
                EnumSet.of(ORDERED, DISTINCT, SIZED),
                EnumSet.of(SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(repeat),
                EnumSet.noneOf(StreamOpFlag.class),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
}
Example 9
Source File: StreamFlagsTest.java    From jdk8u-jdk with GNU General Public License v2.0 5 votes vote down vote up 
public void testBaseStreams() {
    Stream<String> arrayList = new ArrayList<String>().stream();
    Stream<String> linkedList = new LinkedList<String>().stream();
    Stream<String> hashSet = new HashSet<String>().stream();
    Stream<String> treeSet = new TreeSet<String>().stream();
    Stream<String> linkedHashSet = new LinkedHashSet<String>().stream();
    Stream<String> repeat = Stream.generate(() -> "");

    assertFlags(OpTestCase.getStreamFlags(arrayList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedList),
                EnumSet.of(ORDERED, SIZED),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(hashSet),
                EnumSet.of(SIZED, DISTINCT),
                EnumSet.of(ORDERED, SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(treeSet),
                EnumSet.of(ORDERED, SIZED, DISTINCT, SORTED),
                EnumSet.of(SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(linkedHashSet),
                EnumSet.of(ORDERED, DISTINCT, SIZED),
                EnumSet.of(SORTED, SHORT_CIRCUIT));
    assertFlags(OpTestCase.getStreamFlags(repeat),
                EnumSet.noneOf(StreamOpFlag.class),
                EnumSet.of(DISTINCT, SORTED, SHORT_CIRCUIT));
}
Example 10
Source File: TicketCategoryGenerator.java    From alf.io with GNU General Public License v3.0 5 votes vote down vote up 
public static Stream<TicketCategory> generateCategoryStream() {
    AtomicInteger generator = new AtomicInteger();
    return Stream.generate(() -> {
        boolean isBounded = generator.incrementAndGet() % 3 != 0;
        TicketCategory tc = Mockito.mock(TicketCategory.class);
        when(tc.isBounded()).thenReturn(isBounded);
        when(tc.getMaxTickets()).thenReturn(isBounded ? 2 : -1);
        return tc;
    });
}
Example 11
Source File: RandomInsertMutationGenerator.java    From DataflowTemplates with Apache License 2.0 5 votes vote down vote up 
public Stream<MutationGroup> stream() {
  Map<String, TableSupplier> suppliers = new HashMap<>();
  for (Table t : ddl.allTables()) {
    suppliers.put(t.name(), new TableSupplier(t));
  }

  Collection<Table> roots = ddl.rootTables();
  List<Supplier<MutationGroup>> groupSuppliers = new ArrayList<>();
  Random rand = new Random();
  for (Table r : roots) {
    groupSuppliers.add(new TableHierarchySupplier(ddl, r, suppliers, rand));
  }

  return Stream.generate(new DbSupplier(groupSuppliers, rand));
}
Example 12
Source File: RandomValueGenerator.java    From DataflowTemplates with Apache License 2.0 5 votes vote down vote up 
public Stream<Value> valueStream(Column column) {
  return Stream.generate(() -> {
    int threshold = nullThreshold;
    if (column.notNull()) {
      threshold = -1;
    }
    if (random.nextInt(100) < threshold) {
      return generateNullValue(column.type());
    }
    return generate(column);
  });
}
Example 13
Source File: DataStreamGeneratorTest.java    From ignite with Apache License 2.0 5 votes vote down vote up 
/** */
@Test
public void testMapVectors() {
    DataStreamGenerator generator = new DataStreamGenerator() {
        @Override public Stream<LabeledVector<Double>> labeled() {
            return Stream.generate(() -> new LabeledVector<>(VectorUtils.of(1., 2.), 100.));
        }
    };

    generator.mapVectors(v -> VectorUtils.of(2., 1.)).labeled().limit(100).forEach(v -> {
        assertArrayEquals(new double[] {2., 1.}, v.features().asArray(), 1e-7);
        assertEquals(100., v.label(), 1e-7);
    });
}
Example 14
Source File: CreateStreamExample.java    From Apache-Spark-2x-for-Java-Developers with MIT License 4 votes vote down vote up 
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"));

      
}
Example 15
Source File: ArrayDomain.java    From tcases with MIT License 4 votes vote down vote up 
/**
 * Returns a random sequence of values from this domain.
 */
public Stream<DataValue<List<DataValue<T>>>> values( ResolverContext context)
  {
  return Stream.generate( () -> dataValueOf( newArray( context)));
  }
Example 16
Source File: ObjectDomain.java    From tcases with MIT License 4 votes vote down vote up 
/**
 * Returns a random sequence of values from this domain.
 */
public Stream<DataValue<Map<String,DataValue<?>>>> values( ResolverContext context)
  {
  return Stream.generate( () -> dataValueOf( newObject( context)));
  }
Example 17
Source File: AbstractStringDomain.java    From tcases with MIT License 4 votes vote down vote up 
/**
 * Returns a random sequence of possible members of this domain.
 */
protected Stream<String> candidates( ResolverContext context)
  {
  return Stream.generate( () -> newValue( context));
  }
Example 18
Source File: GenTest.java    From QuickTheories with Apache License 2.0 4 votes vote down vote up 
private <T> Stream<T> generate(Gen<T> gen) {
  return Stream.generate( () -> gen.generate(source));
}
Example 19
Source File: ElmScope.java    From elm-plugin with MIT License 4 votes vote down vote up 
public static Stream<Optional<ElmLowerCaseId>> recordFieldsFor(ElmFile file) {
    ElmRecordFieldsProvider p = new ElmRecordFieldsProvider(file);
    return Stream.generate(p::nextField);
}
Example 20
Source File: UnixStream.java    From unix-stream with MIT License 2 votes vote down vote up 
/**
 * Create a new infinite UnixStream from the standard input.
 *
 * @return a new infinite UnixStream from the standard input.
 * @throws IOException thrown if an error occurs during reading the standard input
 */
static UnixStream<String> cat() throws IOException {
    return new UnixStreamImpl<>(Stream.generate(new StandardInputSupplier(new BufferedReader(new InputStreamReader(in)))));
}