From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- libjava/classpath/java/util/LinkedHashSet.java | 159 +++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 libjava/classpath/java/util/LinkedHashSet.java (limited to 'libjava/classpath/java/util/LinkedHashSet.java') diff --git a/libjava/classpath/java/util/LinkedHashSet.java b/libjava/classpath/java/util/LinkedHashSet.java new file mode 100644 index 000000000..2caebaf93 --- /dev/null +++ b/libjava/classpath/java/util/LinkedHashSet.java @@ -0,0 +1,159 @@ +/* LinkedHashSet.java -- a set backed by a LinkedHashMap, for linked + list traversal. + Copyright (C) 2001, 2004, 2005, 2007 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.util; + +import java.io.Serializable; + +/** + * This class provides a hashtable-backed implementation of the + * Set interface, with predictable traversal order. + *

+ * + * It uses a hash-bucket approach; that is, hash collisions are handled + * by linking the new node off of the pre-existing node (or list of + * nodes). In this manner, techniques such as linear probing (which + * can cause primary clustering) and rehashing (which does not fit very + * well with Java's method of precomputing hash codes) are avoided. In + * addition, this maintains a doubly-linked list which tracks insertion + * order. Note that the insertion order is not modified if an + * add simply reinserts an element in the set. + *

+ * + * One of the nice features of tracking insertion order is that you can + * copy a set, and regardless of the implementation of the original, + * produce the same results when iterating over the copy. This is possible + * without needing the overhead of TreeSet. + *

+ * + * Under ideal circumstances (no collisions), LinkedHashSet offers O(1) + * performance on most operations. In the worst case (all elements map + * to the same hash code -- very unlikely), most operations are O(n). + *

+ * + * LinkedHashSet accepts the null entry. It is not synchronized, so if + * you need multi-threaded access, consider using:
+ * Set s = Collections.synchronizedSet(new LinkedHashSet(...)); + *

+ * + * The iterators are fail-fast, meaning that any structural + * modification, except for remove() called on the iterator + * itself, cause the iterator to throw a + * {@link ConcurrentModificationException} rather than exhibit + * non-deterministic behavior. + * + * @author Eric Blake (ebb9@email.byu.edu) + * @see Object#hashCode() + * @see Collection + * @see Set + * @see HashSet + * @see TreeSet + * @see Collections#synchronizedSet(Set) + * @since 1.4 + * @status updated to 1.4 + */ +public class LinkedHashSet extends HashSet + implements Set, Cloneable, Serializable +{ + /** + * Compatible with JDK 1.4. + */ + private static final long serialVersionUID = -2851667679971038690L; + + /** + * Construct a new, empty HashSet whose backing HashMap has the default + * capacity (11) and loadFactor (0.75). + */ + public LinkedHashSet() + { + super(); + } + + /** + * Construct a new, empty HashSet whose backing HashMap has the supplied + * capacity and the default load factor (0.75). + * + * @param initialCapacity the initial capacity of the backing HashMap + * @throws IllegalArgumentException if the capacity is negative + */ + public LinkedHashSet(int initialCapacity) + { + super(initialCapacity); + } + + /** + * Construct a new, empty HashSet whose backing HashMap has the supplied + * capacity and load factor. + * + * @param initialCapacity the initial capacity of the backing HashMap + * @param loadFactor the load factor of the backing HashMap + * @throws IllegalArgumentException if either argument is negative, or + * if loadFactor is POSITIVE_INFINITY or NaN + */ + public LinkedHashSet(int initialCapacity, float loadFactor) + { + super(initialCapacity, loadFactor); + } + + /** + * Construct a new HashSet with the same elements as are in the supplied + * collection (eliminating any duplicates, of course). The backing storage + * has twice the size of the collection, or the default size of 11, + * whichever is greater; and the default load factor (0.75). + * + * @param c a collection of initial set elements + * @throws NullPointerException if c is null + */ + public LinkedHashSet(Collection c) + { + super(c); + } + + /** + * Helper method which initializes the backing Map. + * + * @param capacity the initial capacity + * @param load the initial load factor + * @return the backing HashMap + */ + HashMap init(int capacity, float load) + { + return new LinkedHashMap(capacity, load); + } +} -- cgit v1.2.3