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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 com.google.common.truth.Truth.assertThat;
import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.IteratorTester;
import java.util.Iterator;
import java.util.NoSuchElementException;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
/** Tests for {@link AbstractSequentialIterator}. */
@GwtCompatible(emulated = true)
public class AbstractSequentialIteratorTest 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);
}
};
assertThat(doubled).containsExactly(2, 4, 8, 16, 32).inOrder();
}
public void testSampleCode() {
Iterable<Integer> actual =
new Iterable<Integer>() {
@Override
public Iterator<Integer> iterator() {
Iterator<Integer> powersOfTwo =
new AbstractSequentialIterator<Integer>(1) {
protected Integer computeNext(Integer previous) {
return (previous == 1 << 30) ? null : previous * 2;
}
};
return powersOfTwo;
}
};
assertThat(actual)
.containsExactly(
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)
.inOrder();
}
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 AbstractSequentialIterator<Integer>(first) {
@Override
protected Integer computeNext(Integer previous) {
return (previous == last) ? null : previous * 2;
}
};
}
private static <T> Iterator<T> newEmpty() {
return new AbstractSequentialIterator<T>(null) {
@Override
protected T computeNext(T previous) {
throw new AssertionFailedError();
}
};
}
private static Iterator<Object> newBroken() {
return new AbstractSequentialIterator<Object>("UNUSED") {
@Override
protected Object computeNext(Object previous) {
throw new MyException();
}
};
}
private static class MyException extends RuntimeException {}
}
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