| /* EnumSyntax.java -- |
| Copyright (C) 2003, 2005 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 javax.print.attribute; |
| |
| import java.io.InvalidObjectException; |
| import java.io.ObjectStreamException; |
| import java.io.Serializable; |
| |
| /** |
| * <code>EnumSyntax</code> is the abstract base class of all enumeration |
| * classes in the Java Print Service API. |
| * <p> |
| * Every enumeration class which extends from EnumSyntax provides several |
| * enumeration objects as singletons of its class. |
| * </p> |
| * <p> |
| * Notes for implementing subclasses: |
| * <ul> |
| * <li> |
| * The values of all enumeration singelton instances have to be in a |
| * sequence which may start at any value. See: {@link #getOffset()} |
| * </li> |
| * <li> |
| * Subclasses have to override {@link #getEnumValueTable()} and should |
| * override {@link #getStringTable()} for correct serialization. |
| * </li> |
| * </ul> |
| * </p> |
| * Example: |
| * <pre> |
| * public class PrinterState extends EnumSyntax |
| * { |
| * public static final PrinterState IDLE = new PrinterState(1); |
| * public static final PrinterState PROCESSING = new PrinterState(2); |
| * public static final PrinterState STOPPED = new PrinterState(3); |
| * |
| * protected PrinterState(int value) |
| * { |
| * super(value); |
| * } |
| * |
| * // Overridden because values start not at zero ! |
| * protected int getOffset() |
| * { |
| * return 1; |
| * } |
| * |
| * private static final String[] stringTable = { "idle", "processing", |
| * "stopped" }; |
| * |
| * protected String[] getStringTable() |
| * { |
| * return stringTable; |
| * } |
| * |
| * private static final PrinterState[] enumValueTable = { IDLE, |
| * PROCESSING, STOPPED}; |
| * |
| * protected EnumSyntax[] getEnumValueTable() |
| * { |
| * return enumValueTable; |
| * } |
| * } |
| * </pre> |
| * |
| * @author Michael Koch (konqueror@gmx.de) |
| * @author Wolfgang Baer (WBaer@gmx.de) |
| */ |
| public abstract class EnumSyntax implements Cloneable, Serializable |
| { |
| private static final long serialVersionUID = -2739521845085831642L; |
| |
| private int value; |
| |
| /** |
| * Creates a <code>EnumSyntax</code> object. |
| * |
| * @param value the value to set. |
| */ |
| protected EnumSyntax(int value) |
| { |
| this.value = value; |
| } |
| |
| /** |
| * Returns the value of this enumeration object. |
| * |
| * @return The value. |
| */ |
| public int getValue() |
| { |
| return value; |
| } |
| |
| /** |
| * Clones this object. |
| * |
| * @return A clone of this object. |
| */ |
| public Object clone() |
| { |
| try |
| { |
| return super.clone(); |
| } |
| catch (CloneNotSupportedException e) |
| { |
| // Cannot happen as we implement java.lang.Cloneable. |
| return null; |
| } |
| } |
| |
| /** |
| * Returns the hashcode for this object. |
| * The hashcode is the value of this enumeration object. |
| * |
| * @return The hashcode. |
| */ |
| public int hashCode() |
| { |
| return value; |
| } |
| |
| /** |
| * Returns the string representation for this object. |
| * The string value from <code>getStringTable()</code> method is returned |
| * if subclasses override this method. Otherwise the value of this object |
| * as a string is returned. |
| * |
| * @return The string representation. |
| */ |
| public String toString() |
| { |
| int index = value - getOffset(); |
| String[] table = getStringTable(); |
| |
| if (table != null |
| && index >= 0 |
| && index < table.length) |
| return table[index]; |
| |
| return "" + value; |
| } |
| |
| /** |
| * Returns a table with the enumeration values represented as strings |
| * for this object. |
| * |
| * The default implementation just returns null. Subclasses should |
| * override this method. |
| * |
| * @return The enumeration values as strings. |
| */ |
| protected String[] getStringTable() |
| { |
| return null; |
| } |
| |
| /** |
| * Needed for singelton semantics during deserialisation. |
| * |
| * Subclasses must not override this class. Subclasses have to override |
| * <code>getEnumValueTable()</code> and should override |
| * <code>getStringTable()</code> for correct serialization. |
| * |
| * @return The Object at index <code>value - getOffset()</code> |
| * in getEnumValueTable. |
| * @throws ObjectStreamException if getEnumValueTable() returns null. |
| */ |
| protected Object readResolve() throws ObjectStreamException |
| { |
| EnumSyntax[] table = getEnumValueTable(); |
| if (table == null) |
| throw new InvalidObjectException("Null enumeration value table " |
| + "for class " |
| + this.getClass().toString()); |
| |
| return table[value - getOffset()]; |
| } |
| |
| /** |
| * Returns a table with the enumeration values for this object. |
| * |
| * The default implementation just returns null. Subclasses have to |
| * to override this method for serialization. |
| * |
| * @return The enumeration values. |
| */ |
| protected EnumSyntax[] getEnumValueTable() |
| { |
| return null; |
| } |
| |
| /** |
| * Returns the lowest used value by the enumerations of this class. |
| * |
| * The default implementation returns 0. This is enough if enumerations |
| * start with a zero value. Otherwise subclasses need to override this |
| * method for serialization and return the lowest value they use. |
| * . |
| * @return The lowest used value used. |
| */ |
| protected int getOffset() |
| { |
| return 0; |
| } |
| } |