EnumSyntax.java 文件源码

/**
 * During object input, convert this deserialized enumeration instance to
 * the proper enumeration value defined in the enumeration attribute class.
 *
 * @return  The enumeration singleton value stored at index
 *          <I>i</I>-<I>L</I> in the enumeration value table returned by
 *          {@link #getEnumValueTable() getEnumValueTable()},
 *          where <I>i</I> is this enumeration value's integer value and
 *          <I>L</I> is the value returned by {@link #getOffset()
 *          getOffset()}.
 *
 * @throws ObjectStreamException if the stream can't be deserialised
 * @throws  InvalidObjectException
 *     Thrown if the enumeration value table is null, this enumeration
 *     value's integer value does not correspond to an element in the
 *     enumeration value table, or the corresponding element in the
 *     enumeration value table is null. (Note: {@link
 *     java.io.InvalidObjectException InvalidObjectException} is a subclass
 *     of {@link java.io.ObjectStreamException ObjectStreamException}, which
 *     <CODE>readResolve()</CODE> is declared to throw.)
 */
protected Object readResolve() throws ObjectStreamException {

    EnumSyntax[] theTable = getEnumValueTable();

    if (theTable == null) {
        throw new InvalidObjectException(
                            "Null enumeration value table for class " +
                            getClass());
    }

    int theOffset = getOffset();
    int theIndex = value - theOffset;

    if (0 > theIndex || theIndex >= theTable.length) {
        throw new InvalidObjectException
            ("Integer value = " +  value + " not in valid range " +
             theOffset + ".." + (theOffset + theTable.length - 1) +
             "for class " + getClass());
    }

    EnumSyntax result = theTable[theIndex];
    if (result == null) {
        throw new InvalidObjectException
            ("No enumeration value for integer value = " +
             value + "for class " + getClass());
    }
    return result;
}