From 07b78716af6a9d7c9fd1e94d9baf94a52c873947 Mon Sep 17 00:00:00 2001
From: Andrew Haley
- * Every enumeration class which extends from EnumSyntax provides several
- * enumeration objects as singletons of its class.
- *
- * Notes for implementing subclasses:
- * EnumSyntax
is the abstract base class of all enumeration
- * classes in the Java Print Service API.
- *
- *
- *
- * 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; - * } - * } - *- * - * @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
EnumSyntax
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 getStringTable()
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
- * getEnumValueTable()
and should override
- * getStringTable()
for correct serialization.
- *
- * @return The Object at index value - getOffset()
- * 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;
- }
-}
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