Add GrowthList, an auto-grow on set/add list
bug 34171, including code from Paul Legato git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@170244 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne
parent
2e08f50b6f
commit
1a806b1f2a
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@ -43,6 +43,7 @@ If this causes major headaches to anyone please contact commons-dev at jakarta.a
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<center><h3>NEW CLASSES</h3></center>
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<ul>
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<li>DefaultedMap - Returns a default value when the key is not found, without adding the default value to the map itself [30911]</li>
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<li>GrowthList - Decorator that causes set and indexed add to expand the list rather than throw IndexOutOfBoundsException [34171]</li>
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<li>LoopingListIterator - When the end of the list is reached the iteration continues from the start [30166]</li>
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</ul>
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@ -221,6 +221,9 @@
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<contributor>
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<name>Guilhem Lavaux</name>
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</contributor>
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<contributor>
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<name>Paul Legato</name>
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</contributor>
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<contributor>
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<name>David Leppik</name>
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</contributor>
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@ -0,0 +1,185 @@
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/*
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* Copyright 2005 The Apache Software Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.collections.list;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Collections;
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import java.util.List;
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/**
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* Decorates another <code>List</code> to make it seemlessly grow when
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* indices larger than the list size are used on add and set,
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* avoiding most IndexOutOfBoundsExceptions.
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* <p>
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* This class avoids errors by growing when a set or add method would
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* normally throw an IndexOutOfBoundsException.
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* Note that IndexOutOfBoundsException IS returned for invalid negative indices.
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* <p>
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* Trying to set or add to an index larger than the size will cause the list
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* to grow (using <code>null</code> elements). Clearly, care must be taken
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* not to use excessively large indices, as the internal list will grow to
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* match.
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* <p>
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* Trying to use any method other than add or set with an invalid inde will
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* call the underlying list and probably result in an IndexOutOfBoundsException.
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* <p>
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* Take care when using this list with <code>null</code> values, as
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* <code>null</code> is the value added when growing the list.
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* <p>
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* All sub-lists will access the underlying list directly, and will throw
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* IndexOutOfBoundsExceptions.
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* <p>
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* This class differs from {@link LazyList} because here growth occurs on
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* set and add, where <code>LazyList</code> grows on get. However, they
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* could easily be used together by decorating twice.
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*
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* @see LazyList
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* @since Commons Collections 3.2
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* @version $Revision: 155406 $ $Date$
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*
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* @author Stephen Colebourne
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* @author Paul Legato
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*/
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public class GrowthList extends AbstractSerializableListDecorator {
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/** Serialization version */
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private static final long serialVersionUID = -3620001881672L;
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/**
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* Factory method to create a growth list.
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*
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* @param list the list to decorate, must not be null
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* @throws IllegalArgumentException if list is null
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*/
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public static List decorate(List list) {
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return new GrowthList(list);
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}
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//-----------------------------------------------------------------------
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/**
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* Constructor that uses an ArrayList internally.
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*/
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public GrowthList() {
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super(new ArrayList());
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}
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/**
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* Constructor that uses an ArrayList internally.
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*
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* @param initialSize the initial size of the ArrayList
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* @throws IllegalArgumentException if initial size is invalid
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*/
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public GrowthList(int initialSize) {
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super(new ArrayList(initialSize));
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}
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/**
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* Constructor that wraps (not copies).
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*
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* @param list the list to decorate, must not be null
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* @throws IllegalArgumentException if list is null
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*/
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protected GrowthList(List list) {
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super(list);
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}
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//-----------------------------------------------------------------------
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/**
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* Decorate the add method to perform the growth behaviour.
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* <p>
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* If the requested index is greater than the current size, the list will
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* grow to the new size. Indices between the old size and the requested
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* size will be filled with <code>null</code>.
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* <p>
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* If the index is less than the current size, the value will be added to
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* the underlying list directly.
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* If the index is less than zero, the underlying list is called, which
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* will probably throw an IndexOutOfBoundsException.
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*
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* @param index the index to add at
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* @param element the object to add at the specified index
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* @throws UnsupportedOperationException if the underlying list doesn't implement set
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* @throws ClassCastException if the underlying list rejects the element
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* @throws IllegalArgumentException if the underlying list rejects the element
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*/
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public void add(int index, Object element) {
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int size = getList().size();
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if (index > size) {
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getList().addAll(Collections.nCopies(index - size, null));
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}
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getList().add(index, element);
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}
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//-----------------------------------------------------------------------
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/**
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* Decorate the addAll method to perform the growth behaviour.
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* <p>
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* If the requested index is greater than the current size, the list will
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* grow to the new size. Indices between the old size and the requested
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* size will be filled with <code>null</code>.
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* <p>
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* If the index is less than the current size, the values will be added to
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* the underlying list directly.
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* If the index is less than zero, the underlying list is called, which
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* will probably throw an IndexOutOfBoundsException.
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*
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* @param index the index to add at
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* @param coll the collection to add at the specified index
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* @return true if the list changed
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* @throws UnsupportedOperationException if the underlying list doesn't implement set
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* @throws ClassCastException if the underlying list rejects the element
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* @throws IllegalArgumentException if the underlying list rejects the element
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*/
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public boolean addAll(int index, Collection coll) {
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int size = getList().size();
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boolean result = false;
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if (index > size) {
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getList().addAll(Collections.nCopies(index - size, null));
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result = true;
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}
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return (getList().addAll(index, coll) | result);
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}
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//-----------------------------------------------------------------------
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/**
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* Decorate the set method to perform the growth behaviour.
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* <p>
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* If the requested index is greater than the current size, the list will
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* grow to the new size. Indices between the old size and the requested
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* size will be filled with <code>null</code>.
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* <p>
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* If the index is less than the current size, the value will be set onto
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* the underlying list directly.
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* If the index is less than zero, the underlying list is called, which
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* will probably throw an IndexOutOfBoundsException.
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*
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* @param index the index to set
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* @param element the object to set at the specified index
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* @return the object previously at that index
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* @throws UnsupportedOperationException if the underlying list doesn't implement set
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* @throws ClassCastException if the underlying list rejects the element
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* @throws IllegalArgumentException if the underlying list rejects the element
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*/
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public Object set(int index, Object element) {
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int size = getList().size();
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if (index >= size) {
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getList().addAll(Collections.nCopies((index - size) + 1, null));
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}
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return getList().set(index, element);
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}
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}
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@ -46,8 +46,13 @@ import org.apache.commons.collections.Factory;
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* instance is the fourth element in the list. The first, second,
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* and third element are all set to <code>null</code>.
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* <p>
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* This class differs from {@link GrowthList} because here growth occurs on
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* get, where <code>GrowthList</code> grows on set and add. However, they
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* could easily be used together by decorating twice.
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* <p>
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* This class is Serializable from Commons Collections 3.1.
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*
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* @see GrowthList
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* @since Commons Collections 3.0
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* @version $Revision$ $Date$
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*
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@ -46,6 +46,7 @@ public class TestAll extends TestCase {
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suite.addTest(TestTreeList.suite());
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suite.addTest(TestFixedSizeList.suite());
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suite.addTest(TestGrowthList.suite());
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suite.addTest(TestPredicatedList.suite());
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suite.addTest(TestSetUniqueList.suite());
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suite.addTest(TestSynchronizedList.suite());
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@ -0,0 +1,175 @@
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/*
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* Copyright 2005 The Apache Software Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.collections.list;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.List;
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import junit.framework.Test;
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import junit.framework.TestSuite;
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/**
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* Extension of {@link TestList} for exercising the {@link GrowthList}.
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*
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* @since Commons Collections 3.2
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* @version $Revision: 155406 $ $Date$
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*
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* @author Stephen Colebourne
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*/
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public class TestGrowthList extends AbstractTestList {
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public TestGrowthList(String testName) {
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super(testName);
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}
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public static Test suite() {
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return new TestSuite(TestGrowthList.class);
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}
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public static void main(String args[]) {
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String[] testCaseName = { TestGrowthList.class.getName()};
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junit.textui.TestRunner.main(testCaseName);
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}
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public List makeEmptyList() {
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return new GrowthList();
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}
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public List makeFullList() {
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List list = new ArrayList();
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list.addAll(Arrays.asList(getFullElements()));
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return GrowthList.decorate(list);
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}
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//-----------------------------------------------------------------------
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public void testGrowthAdd() {
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Integer one = new Integer(1);
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GrowthList grower = new GrowthList();
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assertEquals(0, grower.size());
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grower.add(1, one);
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assertEquals(2, grower.size());
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assertEquals(null, grower.get(0));
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assertEquals(one, grower.get(1));
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}
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public void testGrowthAddAll() {
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Integer one = new Integer(1);
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Integer two = new Integer(2);
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Collection coll = new ArrayList();
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coll.add(one);
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coll.add(two);
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GrowthList grower = new GrowthList();
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assertEquals(0, grower.size());
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grower.addAll(1, coll);
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assertEquals(3, grower.size());
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assertEquals(null, grower.get(0));
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assertEquals(one, grower.get(1));
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assertEquals(two, grower.get(2));
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}
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public void testGrowthSet1() {
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Integer one = new Integer(1);
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GrowthList grower = new GrowthList();
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assertEquals(0, grower.size());
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grower.set(1, one);
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assertEquals(2, grower.size());
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assertEquals(null, grower.get(0));
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assertEquals(one, grower.get(1));
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}
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public void testGrowthSet2() {
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Integer one = new Integer(1);
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GrowthList grower = new GrowthList();
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assertEquals(0, grower.size());
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grower.set(0, one);
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assertEquals(1, grower.size());
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assertEquals(one, grower.get(0));
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}
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//-----------------------------------------------------------------------
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/**
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* Override.
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*/
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public void testListAddByIndexBoundsChecking() {
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List list;
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Object element = getOtherElements()[0];
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try {
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list = makeEmptyList();
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list.add(-1, element);
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fail("List.add should throw IndexOutOfBoundsException [-1]");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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}
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/**
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* Override.
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*/
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public void testListAddByIndexBoundsChecking2() {
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List list;
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Object element = getOtherElements()[0];
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try {
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list = makeFullList();
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list.add(-1, element);
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fail("List.add should throw IndexOutOfBoundsException [-1]");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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}
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/**
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* Override.
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*/
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public void testListSetByIndexBoundsChecking() {
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List list = makeEmptyList();
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Object element = getOtherElements()[0];
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try {
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list.set(-1, element);
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fail("List.set should throw IndexOutOfBoundsException [-1]");
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} catch (IndexOutOfBoundsException e) {
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// expected
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}
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}
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/**
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* Override.
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*/
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public void testListSetByIndexBoundsChecking2() {
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List list = makeFullList();
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Object element = getOtherElements()[0];
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try {
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list.set(-1, element);
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fail("List.set should throw IndexOutOfBoundsException [-1]");
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} catch(IndexOutOfBoundsException e) {
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// expected
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}
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}
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//-----------------------------------------------------------------------
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public String getCompatibilityVersion() {
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return "3.2";
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}
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// public void testCreate() throws Exception {
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// resetEmpty();
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// writeExternalFormToDisk((java.io.Serializable) collection, "C:/commons/collections/data/test/GrowthList.emptyCollection.version3.2.obj");
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// resetFull();
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// writeExternalFormToDisk((java.io.Serializable) collection, "C:/commons/collections/data/test/GrowthList.fullCollection.version3.2.obj");
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// }
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}
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