Lambda with static function - Java Lambda Stream

Description

Lambda with static function
Demo Code

public class DataStructure {

    private final static int SIZE = 15;
    private int[] arrayOfInts = new int[SIZE];

    public DataStructure() {
        for (int i = 0; i < SIZE; i++) {
            arrayOfInts[i] = i;// w w w .jav a 2 s.  c o  m
        }
    }

    public int size() {
        return SIZE;
    }

    public int get(int index) {
        return arrayOfInts[index];
    }

    interface DataStructureIterator extends java.util.Iterator<Integer> {
    }

    private class EvenIterator implements DataStructureIterator {

        private int nextIndex = 0;

        public boolean hasNext() {
            return (nextIndex <= SIZE - 1);
        }

        public Integer next() {
            Integer retValue = Integer.valueOf(arrayOfInts[nextIndex]);
            nextIndex += 2;
            return retValue;
        }
    }

    public DataStructureIterator getEvenIterator() {
        return new EvenIterator();
    }

    public void printEven() {
        DataStructureIterator iterator = getEvenIterator();
        while (iterator.hasNext()) {
            System.out.print(iterator.next() + " ");
        }
        System.out.println();
    }

    public void print(DataStructureIterator iterator) {
        while (iterator.hasNext()) {
            System.out.print(iterator.next() + " ");
        }
        System.out.println();
    }

    public void print(java.util.function.Function<Integer, Boolean> function) {
        for (int i = 0; i < SIZE; i++) {
            if (function.apply(i)) {
                System.out.print(arrayOfInts[i] + " ");
            }
        }
        System.out.println();
    }

    public static Boolean isEvenIndex(Integer index) {
        if (index % 2 == 0)
            return Boolean.TRUE;
        return Boolean.FALSE;
    }

    public static Boolean isOddIndex(Integer index) {
        if (index % 2 == 0)
            return Boolean.FALSE;
        return Boolean.TRUE;
    }

    public static void main(String s[]) {
        
    DataStructure ds = new DataStructure();
        
    System.out.println("printEven()");
    ds.printEven();
        
    System.out.println("print(DataStructureIterator) with "    
        + "getEvenIterator");
    ds.print(ds.getEvenIterator());
        
    System.out.println("print(DataStructureIterator) with "
        + "anonymous class, odd indicies");
    ds.print(
        new DataStructure.DataStructureIterator() {
            private int nextIndex = 1;
            public boolean hasNext() {
                return (nextIndex <= ds.size() - 1);
            }
            public Integer next() {
                int retValue = ds.get(nextIndex);
                nextIndex += 2;
                return retValue;
            }
        }
    );
        
    System.out.println("print(Function) with lambda expressions");
    ds.print(index -> {
        if (index % 2 == 0) return Boolean.TRUE;
        return Boolean.FALSE;
    });
    ds.print(index -> {
        if (index % 2 == 0) return Boolean.FALSE;
        return Boolean.TRUE;
    });
        
    System.out.println("print(Function) with method references");
    ds.print(DataStructure::isEvenIndex);
    ds.print(DataStructure::isOddIndex);
}
}

/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
Lambda with static function - Java Lambda Stream

Description

Demo Code

Result

Related Tutorials
