/**

* Copyright 2013 Netflix, Inc.

*

* Licensed 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 rx.util;

import static org.junit.Assert.*;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Iterator;

import java.util.List;

import java.util.NoSuchElementException;

import org.junit.Test;

public final class Range implements Iterable<Integer> {

private final int start;

private final int end;

private final int step;

public static Range createWithCount(int start, int count) {

return create(start, start + count);

}

public static Range create(int start, int end) {

return new Range(start, end, 1);

}

public static Range createWithStep(int start, int end, int step) {

return new Range(start, end, step);

}

private Range(int start, int end, int step) {

this.start = start;

this.end = end;

this.step = step;

}

@Override

public Iterator<Integer> iterator() {

return new Iterator<Integer>() {

private int current = start;

@Override

public boolean hasNext() {

return current < end;

}

@Override

public Integer next() {

if (!hasNext()) {

throw new NoSuchElementException("No more elements");

}

int result = current;

current += step;

return result;

}

@Override

public void remove() {

throw new UnsupportedOperationException("Read only iterator");

}

};

}

@Override

public String toString() {

return "Range (" + start + ", " + end + "), step " + step;

}

public static class UnitTest {

@Test

public void testSimpleRange() {

assertEquals(Arrays.asList(1, 2, 3, 4), toList(Range.create(1, 5)));

}

@Test

public void testRangeWithStep() {

assertEquals(Arrays.asList(1, 3, 5, 7, 9), toList(Range.createWithStep(1, 10, 2)));

}

@Test

public void testRangeWithCount() {

assertEquals(Arrays.asList(1, 2, 3, 4, 5), toList(Range.createWithCount(1, 5)));

}

@Test

public void testRangeWithCount2() {

assertEquals(Arrays.asList(2, 3, 4, 5), toList(Range.createWithCount(2, 4)));

}

@Test

public void testRangeWithCount3() {

assertEquals(Arrays.asList(0, 1, 2, 3), toList(Range.createWithCount(0, 4)));

}

@Test

public void testRangeWithCount4() {

assertEquals(Arrays.asList(10, 11, 12, 13, 14), toList(Range.createWithCount(10, 5)));

}

private static <T> List<T> toList(Iterable<T> iterable) {

List<T> result = new ArrayList<T>();

for (T element : iterable) {

result.add(element);

}

return result;

}

}

}