src/java.base/share/classes/java/util/EnumSet.java
changeset 47216 71c04702a3d5
parent 44743 f0bbd698c486
child 48230 d0e8542ef650
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/EnumSet.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,467 @@
+/*
+ * Copyright (c) 2003, 2014, Oracle and/or its affiliates. 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util;
+
+import jdk.internal.misc.SharedSecrets;
+
+/**
+ * A specialized {@link Set} implementation for use with enum types.  All of
+ * the elements in an enum set must come from a single enum type that is
+ * specified, explicitly or implicitly, when the set is created.  Enum sets
+ * are represented internally as bit vectors.  This representation is
+ * extremely compact and efficient. The space and time performance of this
+ * class should be good enough to allow its use as a high-quality, typesafe
+ * alternative to traditional {@code int}-based "bit flags."  Even bulk
+ * operations (such as {@code containsAll} and {@code retainAll}) should
+ * run very quickly if their argument is also an enum set.
+ *
+ * <p>The iterator returned by the {@code iterator} method traverses the
+ * elements in their <i>natural order</i> (the order in which the enum
+ * constants are declared).  The returned iterator is <i>weakly
+ * consistent</i>: it will never throw {@link ConcurrentModificationException}
+ * and it may or may not show the effects of any modifications to the set that
+ * occur while the iteration is in progress.
+ *
+ * <p>Null elements are not permitted.  Attempts to insert a null element
+ * will throw {@link NullPointerException}.  Attempts to test for the
+ * presence of a null element or to remove one will, however, function
+ * properly.
+ *
+ * <P>Like most collection implementations, {@code EnumSet} is not
+ * synchronized.  If multiple threads access an enum set concurrently, and at
+ * least one of the threads modifies the set, it should be synchronized
+ * externally.  This is typically accomplished by synchronizing on some
+ * object that naturally encapsulates the enum set.  If no such object exists,
+ * the set should be "wrapped" using the {@link Collections#synchronizedSet}
+ * method.  This is best done at creation time, to prevent accidental
+ * unsynchronized access:
+ *
+ * <pre>
+ * Set&lt;MyEnum&gt; s = Collections.synchronizedSet(EnumSet.noneOf(MyEnum.class));
+ * </pre>
+ *
+ * <p>Implementation note: All basic operations execute in constant time.
+ * They are likely (though not guaranteed) to be much faster than their
+ * {@link HashSet} counterparts.  Even bulk operations execute in
+ * constant time if their argument is also an enum set.
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch
+ * @since 1.5
+ * @see EnumMap
+ * @serial exclude
+ */
+@SuppressWarnings("serial") // No serialVersionUID due to usage of
+                            // serial proxy pattern
+public abstract class EnumSet<E extends Enum<E>> extends AbstractSet<E>
+    implements Cloneable, java.io.Serializable
+{
+    /**
+     * The class of all the elements of this set.
+     */
+    final Class<E> elementType;
+
+    /**
+     * All of the values comprising T.  (Cached for performance.)
+     */
+    final Enum<?>[] universe;
+
+    EnumSet(Class<E>elementType, Enum<?>[] universe) {
+        this.elementType = elementType;
+        this.universe    = universe;
+    }
+
+    /**
+     * Creates an empty enum set with the specified element type.
+     *
+     * @param <E> The class of the elements in the set
+     * @param elementType the class object of the element type for this enum
+     *     set
+     * @return An empty enum set of the specified type.
+     * @throws NullPointerException if {@code elementType} is null
+     */
+    public static <E extends Enum<E>> EnumSet<E> noneOf(Class<E> elementType) {
+        Enum<?>[] universe = getUniverse(elementType);
+        if (universe == null)
+            throw new ClassCastException(elementType + " not an enum");
+
+        if (universe.length <= 64)
+            return new RegularEnumSet<>(elementType, universe);
+        else
+            return new JumboEnumSet<>(elementType, universe);
+    }
+
+    /**
+     * Creates an enum set containing all of the elements in the specified
+     * element type.
+     *
+     * @param <E> The class of the elements in the set
+     * @param elementType the class object of the element type for this enum
+     *     set
+     * @return An enum set containing all the elements in the specified type.
+     * @throws NullPointerException if {@code elementType} is null
+     */
+    public static <E extends Enum<E>> EnumSet<E> allOf(Class<E> elementType) {
+        EnumSet<E> result = noneOf(elementType);
+        result.addAll();
+        return result;
+    }
+
+    /**
+     * Adds all of the elements from the appropriate enum type to this enum
+     * set, which is empty prior to the call.
+     */
+    abstract void addAll();
+
+    /**
+     * Creates an enum set with the same element type as the specified enum
+     * set, initially containing the same elements (if any).
+     *
+     * @param <E> The class of the elements in the set
+     * @param s the enum set from which to initialize this enum set
+     * @return A copy of the specified enum set.
+     * @throws NullPointerException if {@code s} is null
+     */
+    public static <E extends Enum<E>> EnumSet<E> copyOf(EnumSet<E> s) {
+        return s.clone();
+    }
+
+    /**
+     * Creates an enum set initialized from the specified collection.  If
+     * the specified collection is an {@code EnumSet} instance, this static
+     * factory method behaves identically to {@link #copyOf(EnumSet)}.
+     * Otherwise, the specified collection must contain at least one element
+     * (in order to determine the new enum set's element type).
+     *
+     * @param <E> The class of the elements in the collection
+     * @param c the collection from which to initialize this enum set
+     * @return An enum set initialized from the given collection.
+     * @throws IllegalArgumentException if {@code c} is not an
+     *     {@code EnumSet} instance and contains no elements
+     * @throws NullPointerException if {@code c} is null
+     */
+    public static <E extends Enum<E>> EnumSet<E> copyOf(Collection<E> c) {
+        if (c instanceof EnumSet) {
+            return ((EnumSet<E>)c).clone();
+        } else {
+            if (c.isEmpty())
+                throw new IllegalArgumentException("Collection is empty");
+            Iterator<E> i = c.iterator();
+            E first = i.next();
+            EnumSet<E> result = EnumSet.of(first);
+            while (i.hasNext())
+                result.add(i.next());
+            return result;
+        }
+    }
+
+    /**
+     * Creates an enum set with the same element type as the specified enum
+     * set, initially containing all the elements of this type that are
+     * <i>not</i> contained in the specified set.
+     *
+     * @param <E> The class of the elements in the enum set
+     * @param s the enum set from whose complement to initialize this enum set
+     * @return The complement of the specified set in this set
+     * @throws NullPointerException if {@code s} is null
+     */
+    public static <E extends Enum<E>> EnumSet<E> complementOf(EnumSet<E> s) {
+        EnumSet<E> result = copyOf(s);
+        result.complement();
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified element.
+     *
+     * Overloadings of this method exist to initialize an enum set with
+     * one through five elements.  A sixth overloading is provided that
+     * uses the varargs feature.  This overloading may be used to create
+     * an enum set initially containing an arbitrary number of elements, but
+     * is likely to run slower than the overloadings that do not use varargs.
+     *
+     * @param <E> The class of the specified element and of the set
+     * @param e the element that this set is to contain initially
+     * @throws NullPointerException if {@code e} is null
+     * @return an enum set initially containing the specified element
+     */
+    public static <E extends Enum<E>> EnumSet<E> of(E e) {
+        EnumSet<E> result = noneOf(e.getDeclaringClass());
+        result.add(e);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified elements.
+     *
+     * Overloadings of this method exist to initialize an enum set with
+     * one through five elements.  A sixth overloading is provided that
+     * uses the varargs feature.  This overloading may be used to create
+     * an enum set initially containing an arbitrary number of elements, but
+     * is likely to run slower than the overloadings that do not use varargs.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param e1 an element that this set is to contain initially
+     * @param e2 another element that this set is to contain initially
+     * @throws NullPointerException if any parameters are null
+     * @return an enum set initially containing the specified elements
+     */
+    public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2) {
+        EnumSet<E> result = noneOf(e1.getDeclaringClass());
+        result.add(e1);
+        result.add(e2);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified elements.
+     *
+     * Overloadings of this method exist to initialize an enum set with
+     * one through five elements.  A sixth overloading is provided that
+     * uses the varargs feature.  This overloading may be used to create
+     * an enum set initially containing an arbitrary number of elements, but
+     * is likely to run slower than the overloadings that do not use varargs.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param e1 an element that this set is to contain initially
+     * @param e2 another element that this set is to contain initially
+     * @param e3 another element that this set is to contain initially
+     * @throws NullPointerException if any parameters are null
+     * @return an enum set initially containing the specified elements
+     */
+    public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3) {
+        EnumSet<E> result = noneOf(e1.getDeclaringClass());
+        result.add(e1);
+        result.add(e2);
+        result.add(e3);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified elements.
+     *
+     * Overloadings of this method exist to initialize an enum set with
+     * one through five elements.  A sixth overloading is provided that
+     * uses the varargs feature.  This overloading may be used to create
+     * an enum set initially containing an arbitrary number of elements, but
+     * is likely to run slower than the overloadings that do not use varargs.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param e1 an element that this set is to contain initially
+     * @param e2 another element that this set is to contain initially
+     * @param e3 another element that this set is to contain initially
+     * @param e4 another element that this set is to contain initially
+     * @throws NullPointerException if any parameters are null
+     * @return an enum set initially containing the specified elements
+     */
+    public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4) {
+        EnumSet<E> result = noneOf(e1.getDeclaringClass());
+        result.add(e1);
+        result.add(e2);
+        result.add(e3);
+        result.add(e4);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified elements.
+     *
+     * Overloadings of this method exist to initialize an enum set with
+     * one through five elements.  A sixth overloading is provided that
+     * uses the varargs feature.  This overloading may be used to create
+     * an enum set initially containing an arbitrary number of elements, but
+     * is likely to run slower than the overloadings that do not use varargs.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param e1 an element that this set is to contain initially
+     * @param e2 another element that this set is to contain initially
+     * @param e3 another element that this set is to contain initially
+     * @param e4 another element that this set is to contain initially
+     * @param e5 another element that this set is to contain initially
+     * @throws NullPointerException if any parameters are null
+     * @return an enum set initially containing the specified elements
+     */
+    public static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4,
+                                                    E e5)
+    {
+        EnumSet<E> result = noneOf(e1.getDeclaringClass());
+        result.add(e1);
+        result.add(e2);
+        result.add(e3);
+        result.add(e4);
+        result.add(e5);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing the specified elements.
+     * This factory, whose parameter list uses the varargs feature, may
+     * be used to create an enum set initially containing an arbitrary
+     * number of elements, but it is likely to run slower than the overloadings
+     * that do not use varargs.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param first an element that the set is to contain initially
+     * @param rest the remaining elements the set is to contain initially
+     * @throws NullPointerException if any of the specified elements are null,
+     *     or if {@code rest} is null
+     * @return an enum set initially containing the specified elements
+     */
+    @SafeVarargs
+    public static <E extends Enum<E>> EnumSet<E> of(E first, E... rest) {
+        EnumSet<E> result = noneOf(first.getDeclaringClass());
+        result.add(first);
+        for (E e : rest)
+            result.add(e);
+        return result;
+    }
+
+    /**
+     * Creates an enum set initially containing all of the elements in the
+     * range defined by the two specified endpoints.  The returned set will
+     * contain the endpoints themselves, which may be identical but must not
+     * be out of order.
+     *
+     * @param <E> The class of the parameter elements and of the set
+     * @param from the first element in the range
+     * @param to the last element in the range
+     * @throws NullPointerException if {@code from} or {@code to} are null
+     * @throws IllegalArgumentException if {@code from.compareTo(to) > 0}
+     * @return an enum set initially containing all of the elements in the
+     *         range defined by the two specified endpoints
+     */
+    public static <E extends Enum<E>> EnumSet<E> range(E from, E to) {
+        if (from.compareTo(to) > 0)
+            throw new IllegalArgumentException(from + " > " + to);
+        EnumSet<E> result = noneOf(from.getDeclaringClass());
+        result.addRange(from, to);
+        return result;
+    }
+
+    /**
+     * Adds the specified range to this enum set, which is empty prior
+     * to the call.
+     */
+    abstract void addRange(E from, E to);
+
+    /**
+     * Returns a copy of this set.
+     *
+     * @return a copy of this set
+     */
+    @SuppressWarnings("unchecked")
+    public EnumSet<E> clone() {
+        try {
+            return (EnumSet<E>) super.clone();
+        } catch(CloneNotSupportedException e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    /**
+     * Complements the contents of this enum set.
+     */
+    abstract void complement();
+
+    /**
+     * Throws an exception if e is not of the correct type for this enum set.
+     */
+    final void typeCheck(E e) {
+        Class<?> eClass = e.getClass();
+        if (eClass != elementType && eClass.getSuperclass() != elementType)
+            throw new ClassCastException(eClass + " != " + elementType);
+    }
+
+    /**
+     * Returns all of the values comprising E.
+     * The result is uncloned, cached, and shared by all callers.
+     */
+    private static <E extends Enum<E>> E[] getUniverse(Class<E> elementType) {
+        return SharedSecrets.getJavaLangAccess()
+                                        .getEnumConstantsShared(elementType);
+    }
+
+    /**
+     * This class is used to serialize all EnumSet instances, regardless of
+     * implementation type.  It captures their "logical contents" and they
+     * are reconstructed using public static factories.  This is necessary
+     * to ensure that the existence of a particular implementation type is
+     * an implementation detail.
+     *
+     * @serial include
+     */
+    private static class SerializationProxy <E extends Enum<E>>
+        implements java.io.Serializable
+    {
+
+        private static final Enum<?>[] ZERO_LENGTH_ENUM_ARRAY = new Enum<?>[0];
+
+        /**
+         * The element type of this enum set.
+         *
+         * @serial
+         */
+        private final Class<E> elementType;
+
+        /**
+         * The elements contained in this enum set.
+         *
+         * @serial
+         */
+        private final Enum<?>[] elements;
+
+        SerializationProxy(EnumSet<E> set) {
+            elementType = set.elementType;
+            elements = set.toArray(ZERO_LENGTH_ENUM_ARRAY);
+        }
+
+        // instead of cast to E, we should perhaps use elementType.cast()
+        // to avoid injection of forged stream, but it will slow the implementation
+        @SuppressWarnings("unchecked")
+        private Object readResolve() {
+            EnumSet<E> result = EnumSet.noneOf(elementType);
+            for (Enum<?> e : elements)
+                result.add((E)e);
+            return result;
+        }
+
+        private static final long serialVersionUID = 362491234563181265L;
+    }
+
+    Object writeReplace() {
+        return new SerializationProxy<>(this);
+    }
+
+    // readObject method for the serialization proxy pattern
+    // See Effective Java, Second Ed., Item 78.
+    private void readObject(java.io.ObjectInputStream stream)
+        throws java.io.InvalidObjectException {
+        throw new java.io.InvalidObjectException("Proxy required");
+    }
+}