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/*
* Copyright (C) 2010 The Guava Authors
*
* 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 com.google.common.collect;
import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
import static org.junit.contrib.truth.Truth.ASSERT;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.IteratorTester;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
import java.util.Iterator;
import java.util.NoSuchElementException;
/** Tests for {@link AbstractLinkedIterator}. */
@GwtCompatible(emulated = true)
public class AbstractLinkedIteratorTest extends TestCase {
@GwtIncompatible("Too slow")
public void testDoublerExhaustive() {
new IteratorTester<Integer>(3, UNMODIFIABLE, ImmutableList.of(1, 2),
IteratorTester.KnownOrder.KNOWN_ORDER) {
@Override
protected Iterator<Integer> newTargetIterator() {
return newDoubler(1, 2);
}
}.test();
}
public void testDoubler() {
Iterable<Integer> doubled = new Iterable<Integer>() {
@Override
public Iterator<Integer> iterator() {
return newDoubler(2, 32);
}
};
ASSERT.that(doubled).hasContentsInOrder(2, 4, 8, 16, 32);
}
public void testSampleCode() {
Iterable<Integer> actual = new Iterable<Integer>() {
@Override
public Iterator<Integer> iterator() {
Iterator<Integer> powersOfTwo = new AbstractLinkedIterator<Integer>(1) {
protected Integer computeNext(Integer previous) {
return (previous == 1 << 30) ? null : previous * 2;
}
};
return powersOfTwo;
}
};
ASSERT.that(actual).hasContentsInOrder(1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096,
8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608,
16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824);
}
public void testEmpty() {
Iterator<Object> empty = newEmpty();
assertFalse(empty.hasNext());
try {
empty.next();
fail();
} catch (NoSuchElementException expected) {
}
try {
empty.remove();
fail();
} catch (UnsupportedOperationException expected) {
}
}
public void testBroken() {
Iterator<Object> broken = newBroken();
assertTrue(broken.hasNext());
// We can't retrieve even the known first element:
try {
broken.next();
fail();
} catch (MyException expected) {
}
try {
broken.next();
fail();
} catch (MyException expected) {
}
}
private static Iterator<Integer> newDoubler(int first, final int last) {
return new AbstractLinkedIterator<Integer>(first) {
@Override
protected Integer computeNext(Integer previous) {
return (previous == last) ? null : previous * 2;
}
};
}
private static <T> Iterator<T> newEmpty() {
return new AbstractLinkedIterator<T>(null) {
@Override
protected T computeNext(T previous) {
throw new AssertionFailedError();
}
};
}
private static Iterator<Object> newBroken() {
return new AbstractLinkedIterator<Object>("UNUSED") {
@Override
protected Object computeNext(Object previous) {
throw new MyException();
}
};
}
private static class MyException extends RuntimeException {}
}
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