--- /dev/null
+/*
+ * @(#)LinkedHashSet.java 1.14 04/02/19
+ *
+ * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
+ * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ */
+
+package instrumented.java15.util;
+
+/**
+ * <p>Hash table and linked list implementation of the <tt>Set</tt> interface,
+ * with predictable iteration order. This implementation differs from
+ * <tt>HashSet</tt> in that it maintains a doubly-linked list running through
+ * all of its entries. This linked list defines the iteration ordering,
+ * which is the order in which elements were inserted into the set
+ * (<i>insertion-order</i>). Note that insertion order is <i>not</i> affected
+ * if an element is <i>re-inserted</i> into the set. (An element <tt>e</tt>
+ * is reinserted into a set <tt>s</tt> if <tt>s.add(e)</tt> is invoked when
+ * <tt>s.contains(e)</tt> would return <tt>true</tt> immediately prior to
+ * the invocation.)
+ *
+ * <p>This implementation spares its clients from the unspecified, generally
+ * chaotic ordering provided by {@link HashSet}, without incurring the
+ * increased cost associated with {@link TreeSet}. It can be used to
+ * produce a copy of a set that has the same order as the original, regardless
+ * of the original set's implementation:
+ * <pre>
+ * void foo(Set m) {
+ * Set copy = new LinkedHashSet(m);
+ * ...
+ * }
+ * </pre>
+ * This technique is particularly useful if a module takes a set on input,
+ * copies it, and later returns results whose order is determined by that of
+ * the copy. (Clients generally appreciate having things returned in the same
+ * order they were presented.)
+ *
+ * <p>This class provides all of the optional <tt>Set</tt> operations, and
+ * permits null elements. Like <tt>HashSet</tt>, it provides constant-time
+ * performance for the basic operations (<tt>add</tt>, <tt>contains</tt> and
+ * <tt>remove</tt>), assuming the hash function disperses elements
+ * properly among the buckets. Performance is likely to be just slightly
+ * below that of <tt>HashSet</tt>, due to the added expense of maintaining the
+ * linked list, with one exception: Iteration over a <tt>LinkedHashSet</tt>
+ * requires time proportional to the <i>size</i> of the set, regardless of
+ * its capacity. Iteration over a <tt>HashSet</tt> is likely to be more
+ * expensive, requiring time proportional to its <i>capacity</i>.
+ *
+ * <p>A linked hash set has two parameters that affect its performance:
+ * <i>initial capacity</i> and <i>load factor</i>. They are defined precisely
+ * as for <tt>HashSet</tt>. Note, however, that the penalty for choosing an
+ * excessively high value for initial capacity is less severe for this class
+ * than for <tt>HashSet</tt>, as iteration times for this class are unaffected
+ * by capacity.
+ *
+ * <p><strong>Note that this implementation is not synchronized.</strong> If
+ * multiple threads access a linked hash set concurrently, and at least one of
+ * the threads modifies the set, it <em>must</em> be synchronized externally.
+ * This is typically accomplished by synchronizing on some object that
+ * naturally encapsulates the set. If no such object exists, the set should
+ * be "wrapped" using the <tt>Collections.synchronizedSet</tt>method. This is
+ * best done at creation time, to prevent accidental unsynchronized access:
+ * <pre>
+ * Set s = Collections.synchronizedSet(new LinkedHashSet(...));
+ * </pre>
+ *
+ * <p>The iterators returned by the this class's <tt>iterator</tt> method are
+ * <em>fail-fast</em>: if the set is modified at any time after the iterator
+ * is created, in any way except through the iterator's own remove method, the
+ * iterator will throw a <tt>ConcurrentModificationException</tt>. Thus, in
+ * the face of concurrent modification, the Iterator fails quickly and
+ * cleanly, rather than risking arbitrary, non-deterministic behavior at an
+ * undetermined time in the future.
+ *
+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
+ * as it is, generally speaking, impossible to make any hard guarantees in the
+ * presence of unsynchronized concurrent modification. Fail-fast iterators
+ * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
+ * Therefore, it would be wrong to write a program that depended on this
+ * exception for its correctness: <i>the fail-fast behavior of iterators
+ * should be used only to detect bugs.</i>
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch
+ * @version 1.14 04/02/19
+ * @see Object#hashCode()
+ * @see Collection
+ * @see Set
+ * @see HashSet
+ * @see TreeSet
+ * @see Hashtable
+ * @since 1.4
+ */
+
+public class LinkedHashSet<E>
+ extends HashSet<E>
+ implements Set<E>, Cloneable, java.io.Serializable {
+
+ private static final long serialVersionUID = -2851667679971038690L;
+
+ /**
+ * Constructs a new, empty linked hash set with the specified initial
+ * capacity and load factor.
+ *
+ * @param initialCapacity the initial capacity of the linked hash set
+ * @param loadFactor the load factor of the linked hash set.
+ * @throws IllegalArgumentException if the initial capacity is less
+ * than zero, or if the load factor is nonpositive.
+ */
+ public LinkedHashSet(int initialCapacity, float loadFactor) {
+ super(initialCapacity, loadFactor, true);
+ }
+
+ /**
+ * Constructs a new, empty linked hash set with the specified initial
+ * capacity and the default load factor (0.75).
+ *
+ * @param initialCapacity the initial capacity of the LinkedHashSet.
+ * @throws IllegalArgumentException if the initial capacity is less
+ * than zero.
+ */
+ public LinkedHashSet(int initialCapacity) {
+ super(initialCapacity, .75f, true);
+ }
+
+ /**
+ * Constructs a new, empty linked hash set with the default initial
+ * capacity (16) and load factor (0.75).
+ */
+ public LinkedHashSet() {
+ super(16, .75f, true);
+ }
+
+ /**
+ * Constructs a new linked hash set with the same elements as the
+ * specified collection. The linked hash set is created with an initial
+ * capacity sufficient to hold the elements in the specified collection
+ * and the default load factor (0.75).
+ *
+ * @param c the collection whose elements are to be placed into
+ * this set.
+ * @throws NullPointerException if the specified collection is null.
+ */
+ public LinkedHashSet(Collection<? extends E> c) {
+ super(Math.max(2*c.size(), 11), .75f, true);
+ addAll(c);
+ }
+}
projects / Benchmarks_CSolver.git / blobdiff