jaroslav@68: /*
jaroslav@68: * Copyright (c) 2003, 2009, Oracle and/or its affiliates. All rights reserved.
jaroslav@68: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@68: *
jaroslav@68: * This code is free software; you can redistribute it and/or modify it
jaroslav@68: * under the terms of the GNU General Public License version 2 only, as
jaroslav@68: * published by the Free Software Foundation. Oracle designates this
jaroslav@68: * particular file as subject to the "Classpath" exception as provided
jaroslav@68: * by Oracle in the LICENSE file that accompanied this code.
jaroslav@68: *
jaroslav@68: * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@68: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@68: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
jaroslav@68: * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@68: * accompanied this code).
jaroslav@68: *
jaroslav@68: * You should have received a copy of the GNU General Public License version
jaroslav@68: * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@68: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@68: *
jaroslav@68: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@68: * or visit www.oracle.com if you need additional information or have any
jaroslav@68: * questions.
jaroslav@68: */
jaroslav@68:
jaroslav@68: package java.lang;
jaroslav@68:
jaroslav@68: import java.io.Serializable;
jaroslav@68: import java.io.IOException;
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * This is the common base class of all Java language enumeration types.
jaroslav@68: *
jaroslav@68: * More information about enums, including descriptions of the
jaroslav@68: * implicitly declared methods synthesized by the compiler, can be
jaroslav@68: * found in section 8.9 of
jaroslav@68: * The Java™ Language Specification.
jaroslav@68: *
jaroslav@68: * Note that when using an enumeration type as the type of a set
jaroslav@68: * or as the type of the keys in a map, specialized and efficient
jaroslav@68: * {@linkplain java.util.EnumSet set} and {@linkplain
jaroslav@68: * java.util.EnumMap map} implementations are available.
jaroslav@68: *
jaroslav@68: * @param The enum type subclass
jaroslav@68: * @author Josh Bloch
jaroslav@68: * @author Neal Gafter
jaroslav@68: * @see Class#getEnumConstants()
jaroslav@68: * @see java.util.EnumSet
jaroslav@68: * @see java.util.EnumMap
jaroslav@68: * @since 1.5
jaroslav@68: */
jaroslav@68: public abstract class Enum>
jaroslav@68: implements Comparable, Serializable {
jaroslav@68: /**
jaroslav@68: * The name of this enum constant, as declared in the enum declaration.
jaroslav@68: * Most programmers should use the {@link #toString} method rather than
jaroslav@68: * accessing this field.
jaroslav@68: */
jaroslav@68: private final String name;
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns the name of this enum constant, exactly as declared in its
jaroslav@68: * enum declaration.
jaroslav@68: *
jaroslav@68: * Most programmers should use the {@link #toString} method in
jaroslav@68: * preference to this one, as the toString method may return
jaroslav@68: * a more user-friendly name. This method is designed primarily for
jaroslav@68: * use in specialized situations where correctness depends on getting the
jaroslav@68: * exact name, which will not vary from release to release.
jaroslav@68: *
jaroslav@68: * @return the name of this enum constant
jaroslav@68: */
jaroslav@68: public final String name() {
jaroslav@68: return name;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * The ordinal of this enumeration constant (its position
jaroslav@68: * in the enum declaration, where the initial constant is assigned
jaroslav@68: * an ordinal of zero).
jaroslav@68: *
jaroslav@68: * Most programmers will have no use for this field. It is designed
jaroslav@68: * for use by sophisticated enum-based data structures, such as
jaroslav@68: * {@link java.util.EnumSet} and {@link java.util.EnumMap}.
jaroslav@68: */
jaroslav@68: private final int ordinal;
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns the ordinal of this enumeration constant (its position
jaroslav@68: * in its enum declaration, where the initial constant is assigned
jaroslav@68: * an ordinal of zero).
jaroslav@68: *
jaroslav@68: * Most programmers will have no use for this method. It is
jaroslav@68: * designed for use by sophisticated enum-based data structures, such
jaroslav@68: * as {@link java.util.EnumSet} and {@link java.util.EnumMap}.
jaroslav@68: *
jaroslav@68: * @return the ordinal of this enumeration constant
jaroslav@68: */
jaroslav@68: public final int ordinal() {
jaroslav@68: return ordinal;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Sole constructor. Programmers cannot invoke this constructor.
jaroslav@68: * It is for use by code emitted by the compiler in response to
jaroslav@68: * enum type declarations.
jaroslav@68: *
jaroslav@68: * @param name - The name of this enum constant, which is the identifier
jaroslav@68: * used to declare it.
jaroslav@68: * @param ordinal - The ordinal of this enumeration constant (its position
jaroslav@68: * in the enum declaration, where the initial constant is assigned
jaroslav@68: * an ordinal of zero).
jaroslav@68: */
jaroslav@68: protected Enum(String name, int ordinal) {
jaroslav@68: this.name = name;
jaroslav@68: this.ordinal = ordinal;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns the name of this enum constant, as contained in the
jaroslav@68: * declaration. This method may be overridden, though it typically
jaroslav@68: * isn't necessary or desirable. An enum type should override this
jaroslav@68: * method when a more "programmer-friendly" string form exists.
jaroslav@68: *
jaroslav@68: * @return the name of this enum constant
jaroslav@68: */
jaroslav@68: public String toString() {
jaroslav@68: return name;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns true if the specified object is equal to this
jaroslav@68: * enum constant.
jaroslav@68: *
jaroslav@68: * @param other the object to be compared for equality with this object.
jaroslav@68: * @return true if the specified object is equal to this
jaroslav@68: * enum constant.
jaroslav@68: */
jaroslav@68: public final boolean equals(Object other) {
jaroslav@68: return this==other;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns a hash code for this enum constant.
jaroslav@68: *
jaroslav@68: * @return a hash code for this enum constant.
jaroslav@68: */
jaroslav@68: public final int hashCode() {
jaroslav@68: return super.hashCode();
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Throws CloneNotSupportedException. This guarantees that enums
jaroslav@68: * are never cloned, which is necessary to preserve their "singleton"
jaroslav@68: * status.
jaroslav@68: *
jaroslav@68: * @return (never returns)
jaroslav@68: */
jaroslav@68: protected final Object clone() throws CloneNotSupportedException {
jaroslav@68: throw new CloneNotSupportedException();
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Compares this enum with the specified object for order. Returns a
jaroslav@68: * negative integer, zero, or a positive integer as this object is less
jaroslav@68: * than, equal to, or greater than the specified object.
jaroslav@68: *
jaroslav@68: * Enum constants are only comparable to other enum constants of the
jaroslav@68: * same enum type. The natural order implemented by this
jaroslav@68: * method is the order in which the constants are declared.
jaroslav@68: */
jaroslav@68: public final int compareTo(E o) {
jaroslav@68: Enum other = (Enum)o;
jaroslav@68: Enum self = this;
jaroslav@68: if (self.getClass() != other.getClass() && // optimization
jaroslav@68: self.getDeclaringClass() != other.getDeclaringClass())
jaroslav@68: throw new ClassCastException();
jaroslav@68: return self.ordinal - other.ordinal;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns the Class object corresponding to this enum constant's
jaroslav@68: * enum type. Two enum constants e1 and e2 are of the
jaroslav@68: * same enum type if and only if
jaroslav@68: * e1.getDeclaringClass() == e2.getDeclaringClass().
jaroslav@68: * (The value returned by this method may differ from the one returned
jaroslav@68: * by the {@link Object#getClass} method for enum constants with
jaroslav@68: * constant-specific class bodies.)
jaroslav@68: *
jaroslav@68: * @return the Class object corresponding to this enum constant's
jaroslav@68: * enum type
jaroslav@68: */
jaroslav@68: public final Class getDeclaringClass() {
jaroslav@68: Class clazz = getClass();
jaroslav@68: Class zuper = clazz.getSuperclass();
jaroslav@68: return (zuper == Enum.class) ? clazz : zuper;
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * Returns the enum constant of the specified enum type with the
jaroslav@68: * specified name. The name must match exactly an identifier used
jaroslav@68: * to declare an enum constant in this type. (Extraneous whitespace
jaroslav@68: * characters are not permitted.)
jaroslav@68: *
jaroslav@68: * Note that for a particular enum type {@code T}, the
jaroslav@68: * implicitly declared {@code public static T valueOf(String)}
jaroslav@68: * method on that enum may be used instead of this method to map
jaroslav@68: * from a name to the corresponding enum constant. All the
jaroslav@68: * constants of an enum type can be obtained by calling the
jaroslav@68: * implicit {@code public static T[] values()} method of that
jaroslav@68: * type.
jaroslav@68: *
jaroslav@68: * @param The enum type whose constant is to be returned
jaroslav@68: * @param enumType the {@code Class} object of the enum type from which
jaroslav@68: * to return a constant
jaroslav@68: * @param name the name of the constant to return
jaroslav@68: * @return the enum constant of the specified enum type with the
jaroslav@68: * specified name
jaroslav@68: * @throws IllegalArgumentException if the specified enum type has
jaroslav@68: * no constant with the specified name, or the specified
jaroslav@68: * class object does not represent an enum type
jaroslav@68: * @throws NullPointerException if {@code enumType} or {@code name}
jaroslav@68: * is null
jaroslav@68: * @since 1.5
jaroslav@68: */
jaroslav@68: public static > T valueOf(Class enumType,
jaroslav@68: String name) {
jaroslav@84: throw new UnsupportedOperationException();
jaroslav@84: // T result = enumType.enumConstantDirectory().get(name);
jaroslav@84: // if (result != null)
jaroslav@84: // return result;
jaroslav@84: // if (name == null)
jaroslav@84: // throw new NullPointerException("Name is null");
jaroslav@84: // throw new IllegalArgumentException(
jaroslav@84: // "No enum constant " + enumType.getCanonicalName() + "." + name);
jaroslav@68: }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * enum classes cannot have finalize methods.
jaroslav@68: */
jaroslav@68: protected final void finalize() { }
jaroslav@68:
jaroslav@68: /**
jaroslav@68: * prevent default deserialization
jaroslav@68: */
jaroslav@84: // private void readObject(ObjectInputStream in) throws IOException,
jaroslav@84: // ClassNotFoundException {
jaroslav@84: // throw new InvalidObjectException("can't deserialize enum");
jaroslav@84: // }
jaroslav@84: //
jaroslav@84: // private void readObjectNoData() throws ObjectStreamException {
jaroslav@84: // throw new InvalidObjectException("can't deserialize enum");
jaroslav@84: // }
jaroslav@68: }