--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/List.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,583 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.util;
+
+/**
+ * An ordered collection (also known as a <i>sequence</i>). The user of this
+ * interface has precise control over where in the list each element is
+ * inserted. The user can access elements by their integer index (position in
+ * the list), and search for elements in the list.<p>
+ *
+ * Unlike sets, lists typically allow duplicate elements. More formally,
+ * lists typically allow pairs of elements <tt>e1</tt> and <tt>e2</tt>
+ * such that <tt>e1.equals(e2)</tt>, and they typically allow multiple
+ * null elements if they allow null elements at all. It is not inconceivable
+ * that someone might wish to implement a list that prohibits duplicates, by
+ * throwing runtime exceptions when the user attempts to insert them, but we
+ * expect this usage to be rare.<p>
+ *
+ * The <tt>List</tt> interface places additional stipulations, beyond those
+ * specified in the <tt>Collection</tt> interface, on the contracts of the
+ * <tt>iterator</tt>, <tt>add</tt>, <tt>remove</tt>, <tt>equals</tt>, and
+ * <tt>hashCode</tt> methods. Declarations for other inherited methods are
+ * also included here for convenience.<p>
+ *
+ * The <tt>List</tt> interface provides four methods for positional (indexed)
+ * access to list elements. Lists (like Java arrays) are zero based. Note
+ * that these operations may execute in time proportional to the index value
+ * for some implementations (the <tt>LinkedList</tt> class, for
+ * example). Thus, iterating over the elements in a list is typically
+ * preferable to indexing through it if the caller does not know the
+ * implementation.<p>
+ *
+ * The <tt>List</tt> interface provides a special iterator, called a
+ * <tt>ListIterator</tt>, that allows element insertion and replacement, and
+ * bidirectional access in addition to the normal operations that the
+ * <tt>Iterator</tt> interface provides. A method is provided to obtain a
+ * list iterator that starts at a specified position in the list.<p>
+ *
+ * The <tt>List</tt> interface provides two methods to search for a specified
+ * object. From a performance standpoint, these methods should be used with
+ * caution. In many implementations they will perform costly linear
+ * searches.<p>
+ *
+ * The <tt>List</tt> interface provides two methods to efficiently insert and
+ * remove multiple elements at an arbitrary point in the list.<p>
+ *
+ * Note: While it is permissible for lists to contain themselves as elements,
+ * extreme caution is advised: the <tt>equals</tt> and <tt>hashCode</tt>
+ * methods are no longer well defined on such a list.
+ *
+ * <p>Some list implementations have restrictions on the elements that
+ * they may contain. For example, some implementations prohibit null elements,
+ * and some have restrictions on the types of their elements. Attempting to
+ * add an ineligible element throws an unchecked exception, typically
+ * <tt>NullPointerException</tt> or <tt>ClassCastException</tt>. Attempting
+ * to query the presence of an ineligible element may throw an exception,
+ * or it may simply return false; some implementations will exhibit the former
+ * behavior and some will exhibit the latter. More generally, attempting an
+ * operation on an ineligible element whose completion would not result in
+ * the insertion of an ineligible element into the list may throw an
+ * exception or it may succeed, at the option of the implementation.
+ * Such exceptions are marked as "optional" in the specification for this
+ * interface.
+ *
+ * <p>This interface is a member of the
+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @see Collection
+ * @see Set
+ * @see ArrayList
+ * @see LinkedList
+ * @see Vector
+ * @see Arrays#asList(Object[])
+ * @see Collections#nCopies(int, Object)
+ * @see Collections#EMPTY_LIST
+ * @see AbstractList
+ * @see AbstractSequentialList
+ * @since 1.2
+ */
+
+public interface List<E> extends Collection<E> {
+ // Query Operations
+
+ /**
+ * Returns the number of elements in this list. If this list contains
+ * more than <tt>Integer.MAX_VALUE</tt> elements, returns
+ * <tt>Integer.MAX_VALUE</tt>.
+ *
+ * @return the number of elements in this list
+ */
+ int size();
+
+ /**
+ * Returns <tt>true</tt> if this list contains no elements.
+ *
+ * @return <tt>true</tt> if this list contains no elements
+ */
+ boolean isEmpty();
+
+ /**
+ * Returns <tt>true</tt> if this list contains the specified element.
+ * More formally, returns <tt>true</tt> if and only if this list contains
+ * at least one element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>.
+ *
+ * @param o element whose presence in this list is to be tested
+ * @return <tt>true</tt> if this list contains the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this list (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * list does not permit null elements (optional)
+ */
+ boolean contains(Object o);
+
+ /**
+ * Returns an iterator over the elements in this list in proper sequence.
+ *
+ * @return an iterator over the elements in this list in proper sequence
+ */
+ Iterator<E> iterator();
+
+ /**
+ * Returns an array containing all of the elements in this list in proper
+ * sequence (from first to last element).
+ *
+ * <p>The returned array will be "safe" in that no references to it are
+ * maintained by this list. (In other words, this method must
+ * allocate a new array even if this list is backed by an array).
+ * The caller is thus free to modify the returned array.
+ *
+ * <p>This method acts as bridge between array-based and collection-based
+ * APIs.
+ *
+ * @return an array containing all of the elements in this list in proper
+ * sequence
+ * @see Arrays#asList(Object[])
+ */
+ Object[] toArray();
+
+ /**
+ * Returns an array containing all of the elements in this list in
+ * proper sequence (from first to last element); the runtime type of
+ * the returned array is that of the specified array. If the list fits
+ * in the specified array, it is returned therein. Otherwise, a new
+ * array is allocated with the runtime type of the specified array and
+ * the size of this list.
+ *
+ * <p>If the list fits in the specified array with room to spare (i.e.,
+ * the array has more elements than the list), the element in the array
+ * immediately following the end of the list is set to <tt>null</tt>.
+ * (This is useful in determining the length of the list <i>only</i> if
+ * the caller knows that the list does not contain any null elements.)
+ *
+ * <p>Like the {@link #toArray()} method, this method acts as bridge between
+ * array-based and collection-based APIs. Further, this method allows
+ * precise control over the runtime type of the output array, and may,
+ * under certain circumstances, be used to save allocation costs.
+ *
+ * <p>Suppose <tt>x</tt> is a list known to contain only strings.
+ * The following code can be used to dump the list into a newly
+ * allocated array of <tt>String</tt>:
+ *
+ * <pre>
+ * String[] y = x.toArray(new String[0]);</pre>
+ *
+ * Note that <tt>toArray(new Object[0])</tt> is identical in function to
+ * <tt>toArray()</tt>.
+ *
+ * @param a the array into which the elements of this list are to
+ * be stored, if it is big enough; otherwise, a new array of the
+ * same runtime type is allocated for this purpose.
+ * @return an array containing the elements of this list
+ * @throws ArrayStoreException if the runtime type of the specified array
+ * is not a supertype of the runtime type of every element in
+ * this list
+ * @throws NullPointerException if the specified array is null
+ */
+ <T> T[] toArray(T[] a);
+
+
+ // Modification Operations
+
+ /**
+ * Appends the specified element to the end of this list (optional
+ * operation).
+ *
+ * <p>Lists that support this operation may place limitations on what
+ * elements may be added to this list. In particular, some
+ * lists will refuse to add null elements, and others will impose
+ * restrictions on the type of elements that may be added. List
+ * classes should clearly specify in their documentation any restrictions
+ * on what elements may be added.
+ *
+ * @param e element to be appended to this list
+ * @return <tt>true</tt> (as specified by {@link Collection#add})
+ * @throws UnsupportedOperationException if the <tt>add</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this list
+ * @throws NullPointerException if the specified element is null and this
+ * list does not permit null elements
+ * @throws IllegalArgumentException if some property of this element
+ * prevents it from being added to this list
+ */
+ boolean add(E e);
+
+ /**
+ * Removes the first occurrence of the specified element from this list,
+ * if it is present (optional operation). If this list does not contain
+ * the element, it is unchanged. More formally, removes the element with
+ * the lowest index <tt>i</tt> such that
+ * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>
+ * (if such an element exists). Returns <tt>true</tt> if this list
+ * contained the specified element (or equivalently, if this list changed
+ * as a result of the call).
+ *
+ * @param o element to be removed from this list, if present
+ * @return <tt>true</tt> if this list contained the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this list (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * list does not permit null elements (optional)
+ * @throws UnsupportedOperationException if the <tt>remove</tt> operation
+ * is not supported by this list
+ */
+ boolean remove(Object o);
+
+
+ // Bulk Modification Operations
+
+ /**
+ * Returns <tt>true</tt> if this list contains all of the elements of the
+ * specified collection.
+ *
+ * @param c collection to be checked for containment in this list
+ * @return <tt>true</tt> if this list contains all of the elements of the
+ * specified collection
+ * @throws ClassCastException if the types of one or more elements
+ * in the specified collection are incompatible with this
+ * list (optional)
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this list does not permit null
+ * elements (optional), or if the specified collection is null
+ * @see #contains(Object)
+ */
+ boolean containsAll(Collection<?> c);
+
+ /**
+ * Appends all of the elements in the specified collection to the end of
+ * this list, in the order that they are returned by the specified
+ * collection's iterator (optional operation). The behavior of this
+ * operation is undefined if the specified collection is modified while
+ * the operation is in progress. (Note that this will occur if the
+ * specified collection is this list, and it's nonempty.)
+ *
+ * @param c collection containing elements to be added to this list
+ * @return <tt>true</tt> if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of an element of the specified
+ * collection prevents it from being added to this list
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this list does not permit null
+ * elements, or if the specified collection is null
+ * @throws IllegalArgumentException if some property of an element of the
+ * specified collection prevents it from being added to this list
+ * @see #add(Object)
+ */
+ boolean addAll(Collection<? extends E> c);
+
+ /**
+ * Inserts all of the elements in the specified collection into this
+ * list at the specified position (optional operation). Shifts the
+ * element currently at that position (if any) and any subsequent
+ * elements to the right (increases their indices). The new elements
+ * will appear in this list in the order that they are returned by the
+ * specified collection's iterator. The behavior of this operation is
+ * undefined if the specified collection is modified while the
+ * operation is in progress. (Note that this will occur if the specified
+ * collection is this list, and it's nonempty.)
+ *
+ * @param index index at which to insert the first element from the
+ * specified collection
+ * @param c collection containing elements to be added to this list
+ * @return <tt>true</tt> if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of an element of the specified
+ * collection prevents it from being added to this list
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this list does not permit null
+ * elements, or if the specified collection is null
+ * @throws IllegalArgumentException if some property of an element of the
+ * specified collection prevents it from being added to this list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * (<tt>index < 0 || index > size()</tt>)
+ */
+ boolean addAll(int index, Collection<? extends E> c);
+
+ /**
+ * Removes from this list all of its elements that are contained in the
+ * specified collection (optional operation).
+ *
+ * @param c collection containing elements to be removed from this list
+ * @return <tt>true</tt> if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of an element of this list
+ * is incompatible with the specified collection (optional)
+ * @throws NullPointerException if this list contains a null element and the
+ * specified collection does not permit null elements (optional),
+ * or if the specified collection is null
+ * @see #remove(Object)
+ * @see #contains(Object)
+ */
+ boolean removeAll(Collection<?> c);
+
+ /**
+ * Retains only the elements in this list that are contained in the
+ * specified collection (optional operation). In other words, removes
+ * from this list all of its elements that are not contained in the
+ * specified collection.
+ *
+ * @param c collection containing elements to be retained in this list
+ * @return <tt>true</tt> if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of an element of this list
+ * is incompatible with the specified collection (optional)
+ * @throws NullPointerException if this list contains a null element and the
+ * specified collection does not permit null elements (optional),
+ * or if the specified collection is null
+ * @see #remove(Object)
+ * @see #contains(Object)
+ */
+ boolean retainAll(Collection<?> c);
+
+ /**
+ * Removes all of the elements from this list (optional operation).
+ * The list will be empty after this call returns.
+ *
+ * @throws UnsupportedOperationException if the <tt>clear</tt> operation
+ * is not supported by this list
+ */
+ void clear();
+
+
+ // Comparison and hashing
+
+ /**
+ * Compares the specified object with this list for equality. Returns
+ * <tt>true</tt> if and only if the specified object is also a list, both
+ * lists have the same size, and all corresponding pairs of elements in
+ * the two lists are <i>equal</i>. (Two elements <tt>e1</tt> and
+ * <tt>e2</tt> are <i>equal</i> if <tt>(e1==null ? e2==null :
+ * e1.equals(e2))</tt>.) In other words, two lists are defined to be
+ * equal if they contain the same elements in the same order. This
+ * definition ensures that the equals method works properly across
+ * different implementations of the <tt>List</tt> interface.
+ *
+ * @param o the object to be compared for equality with this list
+ * @return <tt>true</tt> if the specified object is equal to this list
+ */
+ boolean equals(Object o);
+
+ /**
+ * Returns the hash code value for this list. The hash code of a list
+ * is defined to be the result of the following calculation:
+ * <pre>
+ * int hashCode = 1;
+ * for (E e : list)
+ * hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
+ * </pre>
+ * This ensures that <tt>list1.equals(list2)</tt> implies that
+ * <tt>list1.hashCode()==list2.hashCode()</tt> for any two lists,
+ * <tt>list1</tt> and <tt>list2</tt>, as required by the general
+ * contract of {@link Object#hashCode}.
+ *
+ * @return the hash code value for this list
+ * @see Object#equals(Object)
+ * @see #equals(Object)
+ */
+ int hashCode();
+
+
+ // Positional Access Operations
+
+ /**
+ * Returns the element at the specified position in this list.
+ *
+ * @param index index of the element to return
+ * @return the element at the specified position in this list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * (<tt>index < 0 || index >= size()</tt>)
+ */
+ E get(int index);
+
+ /**
+ * Replaces the element at the specified position in this list with the
+ * specified element (optional operation).
+ *
+ * @param index index of the element to replace
+ * @param element element to be stored at the specified position
+ * @return the element previously at the specified position
+ * @throws UnsupportedOperationException if the <tt>set</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this list
+ * @throws NullPointerException if the specified element is null and
+ * this list does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * (<tt>index < 0 || index >= size()</tt>)
+ */
+ E set(int index, E element);
+
+ /**
+ * Inserts the specified element at the specified position in this list
+ * (optional operation). Shifts the element currently at that position
+ * (if any) and any subsequent elements to the right (adds one to their
+ * indices).
+ *
+ * @param index index at which the specified element is to be inserted
+ * @param element element to be inserted
+ * @throws UnsupportedOperationException if the <tt>add</tt> operation
+ * is not supported by this list
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this list
+ * @throws NullPointerException if the specified element is null and
+ * this list does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * (<tt>index < 0 || index > size()</tt>)
+ */
+ void add(int index, E element);
+
+ /**
+ * Removes the element at the specified position in this list (optional
+ * operation). Shifts any subsequent elements to the left (subtracts one
+ * from their indices). Returns the element that was removed from the
+ * list.
+ *
+ * @param index the index of the element to be removed
+ * @return the element previously at the specified position
+ * @throws UnsupportedOperationException if the <tt>remove</tt> operation
+ * is not supported by this list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * (<tt>index < 0 || index >= size()</tt>)
+ */
+ E remove(int index);
+
+
+ // Search Operations
+
+ /**
+ * Returns the index of the first occurrence of the specified element
+ * in this list, or -1 if this list does not contain the element.
+ * More formally, returns the lowest index <tt>i</tt> such that
+ * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
+ * or -1 if there is no such index.
+ *
+ * @param o element to search for
+ * @return the index of the first occurrence of the specified element in
+ * this list, or -1 if this list does not contain the element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this list (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * list does not permit null elements (optional)
+ */
+ int indexOf(Object o);
+
+ /**
+ * Returns the index of the last occurrence of the specified element
+ * in this list, or -1 if this list does not contain the element.
+ * More formally, returns the highest index <tt>i</tt> such that
+ * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
+ * or -1 if there is no such index.
+ *
+ * @param o element to search for
+ * @return the index of the last occurrence of the specified element in
+ * this list, or -1 if this list does not contain the element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this list (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * list does not permit null elements (optional)
+ */
+ int lastIndexOf(Object o);
+
+
+ // List Iterators
+
+ /**
+ * Returns a list iterator over the elements in this list (in proper
+ * sequence).
+ *
+ * @return a list iterator over the elements in this list (in proper
+ * sequence)
+ */
+ ListIterator<E> listIterator();
+
+ /**
+ * Returns a list iterator over the elements in this list (in proper
+ * sequence), starting at the specified position in the list.
+ * The specified index indicates the first element that would be
+ * returned by an initial call to {@link ListIterator#next next}.
+ * An initial call to {@link ListIterator#previous previous} would
+ * return the element with the specified index minus one.
+ *
+ * @param index index of the first element to be returned from the
+ * list iterator (by a call to {@link ListIterator#next next})
+ * @return a list iterator over the elements in this list (in proper
+ * sequence), starting at the specified position in the list
+ * @throws IndexOutOfBoundsException if the index is out of range
+ * ({@code index < 0 || index > size()})
+ */
+ ListIterator<E> listIterator(int index);
+
+ // View
+
+ /**
+ * Returns a view of the portion of this list between the specified
+ * <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive. (If
+ * <tt>fromIndex</tt> and <tt>toIndex</tt> are equal, the returned list is
+ * empty.) The returned list is backed by this list, so non-structural
+ * changes in the returned list are reflected in this list, and vice-versa.
+ * The returned list supports all of the optional list operations supported
+ * by this list.<p>
+ *
+ * This method eliminates the need for explicit range operations (of
+ * the sort that commonly exist for arrays). Any operation that expects
+ * a list can be used as a range operation by passing a subList view
+ * instead of a whole list. For example, the following idiom
+ * removes a range of elements from a list:
+ * <pre>
+ * list.subList(from, to).clear();
+ * </pre>
+ * Similar idioms may be constructed for <tt>indexOf</tt> and
+ * <tt>lastIndexOf</tt>, and all of the algorithms in the
+ * <tt>Collections</tt> class can be applied to a subList.<p>
+ *
+ * The semantics of the list returned by this method become undefined if
+ * the backing list (i.e., this list) is <i>structurally modified</i> in
+ * any way other than via the returned list. (Structural modifications are
+ * those that change the size of this list, or otherwise perturb it in such
+ * a fashion that iterations in progress may yield incorrect results.)
+ *
+ * @param fromIndex low endpoint (inclusive) of the subList
+ * @param toIndex high endpoint (exclusive) of the subList
+ * @return a view of the specified range within this list
+ * @throws IndexOutOfBoundsException for an illegal endpoint index value
+ * (<tt>fromIndex < 0 || toIndex > size ||
+ * fromIndex > toIndex</tt>)
+ */
+ List<E> subList(int fromIndex, int toIndex);
+}