From bfd74a869ebf4c0f5c1e76bcaa87e09d85b4bede Mon Sep 17 00:00:00 2001 From: Ben Gruver Date: Mon, 31 Dec 2012 17:36:54 -0800 Subject: [PATCH] Create AbstractForwardSequentialList util class --- .../util/AbstractForwardSequentialList.java | 118 ++++++++++ .../AbstractForwardSequentialListTest.java | 214 ++++++++++++++++++ 2 files changed, 332 insertions(+) create mode 100644 util/src/main/java/org/jf/util/AbstractForwardSequentialList.java create mode 100644 util/src/test/java/org/jf/util/AbstractForwardSequentialListTest.java diff --git a/util/src/main/java/org/jf/util/AbstractForwardSequentialList.java b/util/src/main/java/org/jf/util/AbstractForwardSequentialList.java new file mode 100644 index 00000000..19739e63 --- /dev/null +++ b/util/src/main/java/org/jf/util/AbstractForwardSequentialList.java @@ -0,0 +1,118 @@ +/* + * Copyright 2012, Google Inc. + * 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 Google Inc. nor 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. + */ + +package org.jf.util; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; +import java.util.AbstractSequentialList; +import java.util.Iterator; +import java.util.ListIterator; +import java.util.NoSuchElementException; + +public abstract class AbstractForwardSequentialList extends AbstractSequentialList { + + @Nonnull private Iterator iterator(int index) { + if (index < 0) { + throw new NoSuchElementException(); + } + + Iterator it = iterator(); + for (int i=0; i iterator(); + + @Override @Nonnull public ListIterator listIterator(final int initialIndex) { + + final Iterator initialIterator; + try { + initialIterator = iterator(initialIndex); + } catch (NoSuchElementException ex) { + throw new IndexOutOfBoundsException(); + } + + return new AbstractListIterator() { + private int index = initialIndex - 1; + @Nullable private Iterator forwardIterator = initialIterator; + + @Nonnull + private Iterator getForwardIterator() { + if (forwardIterator == null) { + try { + forwardIterator = iterator(index+1); + } catch (IndexOutOfBoundsException ex) { + throw new NoSuchElementException(); + } + } + return forwardIterator; + } + + @Override public boolean hasNext() { + return getForwardIterator().hasNext(); + } + + @Override public boolean hasPrevious() { + return index >= 0; + } + + @Override public T next() { + T ret = getForwardIterator().next(); + index++; + return ret; + } + + @Override public int nextIndex() { + return index+1; + } + + @Override public T previous() { + forwardIterator = null; + try { + return iterator(index--).next(); + } catch (IndexOutOfBoundsException ex) { + throw new NoSuchElementException(); + } + } + + @Override public int previousIndex() { + return index; + } + }; + } + + @Override @Nonnull public ListIterator listIterator() { + return listIterator(0); + } +} diff --git a/util/src/test/java/org/jf/util/AbstractForwardSequentialListTest.java b/util/src/test/java/org/jf/util/AbstractForwardSequentialListTest.java new file mode 100644 index 00000000..6b52320d --- /dev/null +++ b/util/src/test/java/org/jf/util/AbstractForwardSequentialListTest.java @@ -0,0 +1,214 @@ +/* + * Copyright 2012, Google Inc. + * 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 Google Inc. nor 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. + */ + +package org.jf.util; + +import junit.framework.Assert; +import org.junit.Before; +import org.junit.Test; + +import javax.annotation.Nonnull; +import java.util.Iterator; +import java.util.List; +import java.util.ListIterator; +import java.util.NoSuchElementException; + +public class AbstractForwardSequentialListTest { + private List list; + + @Before + public void setup() { + list = new AbstractForwardSequentialList() { + @Nonnull @Override public Iterator iterator() { + return new Iterator() { + private int index = 0; + + @Override public boolean hasNext() { + return index < 100; + } + + @Override public Integer next() { + if (!hasNext()) { + throw new NoSuchElementException(); + } + return index++; + } + + @Override public void remove() { + throw new UnsupportedOperationException(); + } + }; + } + + @Override public int size() { + return 100; + } + }; + } + + private void testForwardIterationImpl(ListIterator iter) { + Assert.assertFalse(iter.hasPrevious()); + + for (int i=0; i<100; i++) { + Assert.assertEquals(i, iter.nextIndex()); + Assert.assertEquals(i-1, iter.previousIndex()); + + Assert.assertTrue(iter.hasNext()); + + Assert.assertEquals(i, iter.next().intValue()); + Assert.assertTrue(iter.hasPrevious()); + } + + Assert.assertFalse(iter.hasNext()); + Assert.assertEquals(iter.nextIndex(), 100); + Assert.assertEquals(iter.previousIndex(), 99); + } + + @Test + public void testForwardIteration() { + testForwardIterationImpl(list.listIterator()); + } + + private void testReverseIterationImpl(ListIterator iter) { + Assert.assertFalse(iter.hasNext()); + + for (int i=99; i>=0; i--) { + Assert.assertEquals(i+1, iter.nextIndex()); + Assert.assertEquals(i, iter.previousIndex()); + + Assert.assertTrue(iter.hasPrevious()); + + Assert.assertEquals(i, iter.previous().intValue()); + Assert.assertTrue(iter.hasNext()); + } + + Assert.assertFalse(iter.hasPrevious()); + Assert.assertEquals(0, iter.nextIndex()); + Assert.assertEquals(-1, iter.previousIndex()); + } + + @Test + public void testReverseIteration() { + testReverseIterationImpl(list.listIterator(100)); + } + + @Test + public void testAlternatingIteration() { + ListIterator iter = list.listIterator(50); + + for (int i=0; i<10; i++) { + Assert.assertTrue(iter.hasNext()); + Assert.assertTrue(iter.hasPrevious()); + Assert.assertEquals(50, iter.nextIndex()); + Assert.assertEquals(49, iter.previousIndex()); + + Assert.assertEquals(50, iter.next().intValue()); + + Assert.assertTrue(iter.hasNext()); + Assert.assertTrue(iter.hasPrevious()); + Assert.assertEquals(51, iter.nextIndex()); + Assert.assertEquals(50, iter.previousIndex()); + + Assert.assertEquals(50, iter.previous().intValue()); + } + } + + @Test + public void testAlternatingIteration2() { + ListIterator iter = list.listIterator(0); + + for (int i=0; i<10; i++) { + testForwardIterationImpl(iter); + testReverseIterationImpl(iter); + } + } + + @Test(expected = IndexOutOfBoundsException.class) + public void testNegativeIndex() { + list.listIterator(-1); + } + + @Test(expected = IndexOutOfBoundsException.class) + public void testLargeIndex() { + list.listIterator(101); + } + + @Test(expected = IndexOutOfBoundsException.class) + public void testLargeIndex2() { + list.listIterator(1000000); + } + + @Test + public void testForwardIterationException() { + // note: no "expected = NoSuchElementException", because we want to make sure the exception occurs only during + // the last call to next() + + ListIterator iter = list.listIterator(0); + for (int i=0; i<100; i++) { + iter.next(); + } + try { + iter.next(); + } catch (NoSuchElementException ex) { + return; + } + Assert.fail(); + } + + @Test(expected = NoSuchElementException.class) + public void testForwardIterationException2() { + ListIterator iter = list.listIterator(100); + iter.next(); + } + + @Test + public void testReverseIterationException() { + // note: no "expected = NoSuchElementException", because we want to make sure the exception occurs only during + // the last call to previous() + + ListIterator iter = list.listIterator(100); + for (int i=0; i<100; i++) { + iter.previous(); + } + try { + iter.previous(); + } catch (NoSuchElementException ex) { + return; + } + Assert.fail(); + } + + @Test(expected = NoSuchElementException.class) + public void testReverseIterationException2() { + ListIterator iter = list.listIterator(0); + iter.previous(); + } +}