--- /dev/null
+/*
+ * @(#)Set.java 1.35 04/02/19
+ *
+ * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
+ * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ */
+
+package instrumented.java15.util;
+
+/**
+ * A collection that contains no duplicate elements. More formally, sets
+ * contain no pair of elements <code>e1</code> and <code>e2</code> such that
+ * <code>e1.equals(e2)</code>, and at most one null element. As implied by
+ * its name, this interface models the mathematical <i>set</i> abstraction.<p>
+ *
+ * The <tt>Set</tt> interface places additional stipulations, beyond those
+ * inherited from the <tt>Collection</tt> interface, on the contracts of all
+ * constructors and on the contracts of the <tt>add</tt>, <tt>equals</tt> and
+ * <tt>hashCode</tt> methods. Declarations for other inherited methods are
+ * also included here for convenience. (The specifications accompanying these
+ * declarations have been tailored to the <tt>Set</tt> interface, but they do
+ * not contain any additional stipulations.)<p>
+ *
+ * The additional stipulation on constructors is, not surprisingly,
+ * that all constructors must create a set that contains no duplicate elements
+ * (as defined above).<p>
+ *
+ * Note: Great care must be exercised if mutable objects are used as set
+ * elements. The behavior of a set is not specified if the value of an object
+ * is changed in a manner that affects equals comparisons while the object is
+ * an element in the set. A special case of this prohibition is that it is
+ * not permissible for a set to contain itself as an element.
+ *
+ * <p>Some set 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 set 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}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch
+ * @author Neal Gafter
+ * @version 1.35, 02/19/04
+ * @see Collection
+ * @see List
+ * @see SortedSet
+ * @see HashSet
+ * @see TreeSet
+ * @see AbstractSet
+ * @see Collections#singleton(java.lang.Object)
+ * @see Collections#EMPTY_SET
+ * @since 1.2
+ */
+
+public interface Set<E> extends Collection<E> {
+ // Query Operations
+
+ /**
+ * Returns the number of elements in this set (its cardinality). If this
+ * set contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
+ * <tt>Integer.MAX_VALUE</tt>.
+ *
+ * @return the number of elements in this set (its cardinality).
+ */
+ int size();
+
+ /**
+ * Returns <tt>true</tt> if this set contains no elements.
+ *
+ * @return <tt>true</tt> if this set contains no elements.
+ */
+ boolean isEmpty();
+
+ /**
+ * Returns <tt>true</tt> if this set contains the specified element. More
+ * formally, returns <tt>true</tt> if and only if this set contains an
+ * element <code>e</code> such that <code>(o==null ? e==null :
+ * o.equals(e))</code>.
+ *
+ * @param o element whose presence in this set is to be tested.
+ * @return <tt>true</tt> if this set contains the specified element.
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this set (optional).
+ * @throws NullPointerException if the specified element is null and this
+ * set does not support null elements (optional).
+ */
+ boolean contains(Object o);
+
+ /**
+ * Returns an iterator over the elements in this set. The elements are
+ * returned in no particular order (unless this set is an instance of some
+ * class that provides a guarantee).
+ *
+ * @return an iterator over the elements in this set.
+ */
+ Iterator<E> iterator();
+
+ /**
+ * Returns an array containing all of the elements in this set.
+ * Obeys the general contract of the <tt>Collection.toArray</tt> method.
+ *
+ * @return an array containing all of the elements in this set.
+ */
+ Object[] toArray();
+
+ /**
+ * Returns an array containing all of the elements in this set; the
+ * runtime type of the returned array is that of the specified array.
+ * Obeys the general contract of the
+ * <tt>Collection.toArray(Object[])</tt> method.
+ *
+ * @param a the array into which the elements of this set 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 set.
+ * @throws ArrayStoreException the runtime type of a is not a supertype
+ * of the runtime type of every element in this set.
+ * @throws NullPointerException if the specified array is <tt>null</tt>.
+ */
+ <T> T[] toArray(T[] a);
+
+
+ // Modification Operations
+
+ /**
+ * Adds the specified element to this set if it is not already present
+ * (optional operation). More formally, adds the specified element,
+ * <code>o</code>, to this set if this set contains no element
+ * <code>e</code> such that <code>(o==null ? e==null :
+ * o.equals(e))</code>. If this set already contains the specified
+ * element, the call leaves this set unchanged and returns <tt>false</tt>.
+ * In combination with the restriction on constructors, this ensures that
+ * sets never contain duplicate elements.<p>
+ *
+ * The stipulation above does not imply that sets must accept all
+ * elements; sets may refuse to add any particular element, including
+ * <tt>null</tt>, and throwing an exception, as described in the
+ * specification for <tt>Collection.add</tt>. Individual set
+ * implementations should clearly document any restrictions on the
+ * elements that they may contain.
+ *
+ * @param o element to be added to this set.
+ * @return <tt>true</tt> if this set did not already contain the specified
+ * element.
+ *
+ * @throws UnsupportedOperationException if the <tt>add</tt> method is not
+ * supported by this set.
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this set.
+ * @throws NullPointerException if the specified element is null and this
+ * set does not support null elements.
+ * @throws IllegalArgumentException if some aspect of the specified element
+ * prevents it from being added to this set.
+ */
+ boolean add(E o);
+
+
+ /**
+ * Removes the specified element from this set if it is present (optional
+ * operation). More formally, removes an element <code>e</code> such that
+ * <code>(o==null ? e==null : o.equals(e))</code>, if the set contains
+ * such an element. Returns <tt>true</tt> if the set contained the
+ * specified element (or equivalently, if the set changed as a result of
+ * the call). (The set will not contain the specified element once the
+ * call returns.)
+ *
+ * @param o object to be removed from this set, if present.
+ * @return true if the set contained the specified element.
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this set (optional).
+ * @throws NullPointerException if the specified element is null and this
+ * set does not support null elements (optional).
+ * @throws UnsupportedOperationException if the <tt>remove</tt> method is
+ * not supported by this set.
+ */
+ boolean remove(Object o);
+
+
+ // Bulk Operations
+
+ /**
+ * Returns <tt>true</tt> if this set contains all of the elements of the
+ * specified collection. If the specified collection is also a set, this
+ * method returns <tt>true</tt> if it is a <i>subset</i> of this set.
+ *
+ * @param c collection to be checked for containment in this set.
+ * @return <tt>true</tt> if this set 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
+ * set (optional).
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this set does not support null
+ * elements (optional).
+ * @throws NullPointerException if the specified collection is
+ * <tt>null</tt>.
+ * @see #contains(Object)
+ */
+ boolean containsAll(Collection<?> c);
+
+ /**
+ * Adds all of the elements in the specified collection to this set if
+ * they're not already present (optional operation). If the specified
+ * collection is also a set, the <tt>addAll</tt> operation effectively
+ * modifies this set so that its value is the <i>union</i> of the two
+ * sets. The behavior of this operation is unspecified if the specified
+ * collection is modified while the operation is in progress.
+ *
+ * @param c collection whose elements are to be added to this set.
+ * @return <tt>true</tt> if this set changed as a result of the call.
+ *
+ * @throws UnsupportedOperationException if the <tt>addAll</tt> method is
+ * not supported by this set.
+ * @throws ClassCastException if the class of some element of the
+ * specified collection prevents it from being added to this
+ * set.
+ * @throws NullPointerException if the specified collection contains one
+ * or more null elements and this set does not support null
+ * elements, or if the specified collection is <tt>null</tt>.
+ * @throws IllegalArgumentException if some aspect of some element of the
+ * specified collection prevents it from being added to this
+ * set.
+ * @see #add(Object)
+ */
+ boolean addAll(Collection<? extends E> c);
+
+ /**
+ * Retains only the elements in this set that are contained in the
+ * specified collection (optional operation). In other words, removes
+ * from this set all of its elements that are not contained in the
+ * specified collection. If the specified collection is also a set, this
+ * operation effectively modifies this set so that its value is the
+ * <i>intersection</i> of the two sets.
+ *
+ * @param c collection that defines which elements this set will retain.
+ * @return <tt>true</tt> if this collection changed as a result of the
+ * call.
+ * @throws UnsupportedOperationException if the <tt>retainAll</tt> method
+ * is not supported by this Collection.
+ * @throws ClassCastException if the types of one or more elements in this
+ * set are incompatible with the specified collection
+ * (optional).
+ * @throws NullPointerException if this set contains a null element and
+ * the specified collection does not support null elements
+ * (optional).
+ * @throws NullPointerException if the specified collection is
+ * <tt>null</tt>.
+ * @see #remove(Object)
+ */
+ boolean retainAll(Collection<?> c);
+
+
+ /**
+ * Removes from this set all of its elements that are contained in the
+ * specified collection (optional operation). If the specified
+ * collection is also a set, this operation effectively modifies this
+ * set so that its value is the <i>asymmetric set difference</i> of
+ * the two sets.
+ *
+ * @param c collection that defines which elements will be removed from
+ * this set.
+ * @return <tt>true</tt> if this set changed as a result of the call.
+ *
+ * @throws UnsupportedOperationException if the <tt>removeAll</tt>
+ * method is not supported by this Collection.
+ * @throws ClassCastException if the types of one or more elements in this
+ * set are incompatible with the specified collection
+ * (optional).
+ * @throws NullPointerException if this set contains a null element and
+ * the specified collection does not support null elements
+ * (optional).
+ * @throws NullPointerException if the specified collection is
+ * <tt>null</tt>.
+ * @see #remove(Object)
+ */
+ boolean removeAll(Collection<?> c);
+
+ /**
+ * Removes all of the elements from this set (optional operation).
+ * This set will be empty after this call returns (unless it throws an
+ * exception).
+ *
+ * @throws UnsupportedOperationException if the <tt>clear</tt> method
+ * is not supported by this set.
+ */
+ void clear();
+
+
+ // Comparison and hashing
+
+ /**
+ * Compares the specified object with this set for equality. Returns
+ * <tt>true</tt> if the specified object is also a set, the two sets
+ * have the same size, and every member of the specified set is
+ * contained in this set (or equivalently, every member of this set is
+ * contained in the specified set). This definition ensures that the
+ * equals method works properly across different implementations of the
+ * set interface.
+ *
+ * @param o Object to be compared for equality with this set.
+ * @return <tt>true</tt> if the specified Object is equal to this set.
+ */
+ boolean equals(Object o);
+
+ /**
+ *
+ * Returns the hash code value for this set. The hash code of a set is
+ * defined to be the sum of the hash codes of the elements in the set,
+ * where the hashcode of a <tt>null</tt> element is defined to be zero.
+ * This ensures that <code>s1.equals(s2)</code> implies that
+ * <code>s1.hashCode()==s2.hashCode()</code> for any two sets
+ * <code>s1</code> and <code>s2</code>, as required by the general
+ * contract of the <tt>Object.hashCode</tt> method.
+ *
+ * @return the hash code value for this set.
+ * @see Object#hashCode()
+ * @see Object#equals(Object)
+ * @see Set#equals(Object)
+ */
+ int hashCode();
+}