format.java

java源代码 请看看啊 提点宝贵的意见

     * to the index after the last character used (parsing does not necessarily
     * use all characters up to the end of the string), and the parsed
     * object is returned. The updated <code>pos</code> can be used to
     * indicate the starting point for the next call to this method.
     * If an error occurs, then the index of <code>pos</code> is not
     * changed, the error index of <code>pos</code> is set to the index of
     * the character where the error occurred, and null is returned.
     *
     * @param source A <code>String</code>, part of which should be parsed.
     * @param pos A <code>ParsePosition</code> object with index and error
     *            index information as described above.
     * @return An <code>Object</code> parsed from the string. In case of
     *         error, returns null.
     * @exception NullPointerException if <code>pos</code> is null.
     */
    public abstract Object parseObject (String source, ParsePosition pos);

    /**
     * Parses text from the beginning of the given string to produce an object.
     * The method may not use the entire text of the given string.
     *
     * @param source A <code>String</code> whose beginning should be parsed.
     * @return An <code>Object</code> parsed from the string.
     * @exception ParseException if the beginning of the specified string
     *            cannot be parsed.
     */
    public Object parseObject(String source) throws ParseException {
        ParsePosition pos = new ParsePosition(0);
        Object result = parseObject(source, pos);
        if (pos.index == 0) {
            throw new ParseException("Format.parseObject(String) failed",
                pos.errorIndex);
        }
        return result;
    }

    /**
     * Creates and returns a copy of this object.
     *
     * @return a clone of this instance.
     */
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            // will never happen
            return null;
        }
    }

    //
    // Convenience methods for creating AttributedCharacterIterators from
    // different parameters.
    // 

    /**
     * Creates an <code>AttributedCharacterIterator</code> for the String
     * <code>s</code>.
     *
     * @param s String to create AttributedCharacterIterator from
     * @return AttributedCharacterIterator wrapping s
     */
    AttributedCharacterIterator createAttributedCharacterIterator(String s) {
	AttributedString as = new AttributedString(s);

	return as.getIterator();
    }

    /**
     * Creates an <code>AttributedCharacterIterator</code> containg the
     * concatenated contents of the passed in
     * <code>AttributedCharacterIterator</code>s.
     *
     * @param iterators AttributedCharacterIterators used to create resulting
     *                  AttributedCharacterIterators
     * @return AttributedCharacterIterator wrapping passed in
     *         AttributedCharacterIterators
     */
    AttributedCharacterIterator createAttributedCharacterIterator(
                       AttributedCharacterIterator[] iterators) {
        AttributedString as = new AttributedString(iterators);

        return as.getIterator();
    }

    /**
     * Returns an AttributedCharacterIterator with the String
     * <code>string</code> and additional key/value pair <code>key</code>,
     * <code>value</code>.
     *
     * @param string String to create AttributedCharacterIterator from
     * @param key Key for AttributedCharacterIterator
     * @param value Value associated with key in AttributedCharacterIterator
     * @return AttributedCharacterIterator wrapping args
     */
    AttributedCharacterIterator createAttributedCharacterIterator(
                      String string, AttributedCharacterIterator.Attribute key,
                      Object value) {
        AttributedString as = new AttributedString(string);

        as.addAttribute(key, value);
        return as.getIterator();
    }

    /**
     * Creates an AttributedCharacterIterator with the contents of
     * <code>iterator</code> and the additional attribute <code>key</code>
     * <code>value</code>.
     *
     * @param iterator Initial AttributedCharacterIterator to add arg to
     * @param key Key for AttributedCharacterIterator
     * @param value Value associated with key in AttributedCharacterIterator
     * @return AttributedCharacterIterator wrapping args
     */
    AttributedCharacterIterator createAttributedCharacterIterator(
	      AttributedCharacterIterator iterator,
              AttributedCharacterIterator.Attribute key, Object value) {
	AttributedString as = new AttributedString(iterator);

	as.addAttribute(key, value);
	return as.getIterator();
    }


    /**
     * Defines constants that are used as attribute keys in the
     * <code>AttributedCharacterIterator</code> returned
     * from <code>Format.formatToCharacterIterator</code> and as
     * field identifiers in <code>FieldPosition</code>.
     *
     * @since 1.4
     */
    public static class Field extends AttributedCharacterIterator.Attribute {
        /**
         * Creates a Field with the specified name.
         *
         * @param name Name of the attribute
         */
        protected Field(String name) {
            super(name);
        }
    }


    /**
     * FieldDelegate is notified by the various <code>Format</code>
     * implementations as they are formatting the Objects. This allows for
     * storage of the individual sections of the formatted String for
     * later use, such as in a <code>FieldPosition</code> or for an
     * <code>AttributedCharacterIterator</code>.
     * <p>
     * Delegates should NOT assume that the <code>Format</code> will notify
     * the delegate of fields in any particular order.
     *
     * @see FieldPosition.Delegate
     * @see CharacterIteratorFieldDelegate
     */
    interface FieldDelegate {
        /**
         * Notified when a particular region of the String is formatted. This
         * method will be invoked if there is no corresponding integer field id
         * matching <code>attr</code>.
         *
         * @param attr Identifies the field matched
         * @param value Value associated with the field
         * @param start Beginning location of the field, will be >= 0
         * @param end End of the field, will be >= start and <= buffer.length()
         * @param buffer Contains current formatted value, receiver should
         *        NOT modify it.
         */
        public void formatted(Format.Field attr, Object value, int start,
                              int end, StringBuffer buffer);

        /**
         * Notified when a particular region of the String is formatted.
         *
         * @param fieldID Identifies the field by integer
         * @param attr Identifies the field matched
         * @param value Value associated with the field
         * @param start Beginning location of the field, will be >= 0
         * @param end End of the field, will be >= start and <= buffer.length()
         * @param buffer Contains current formatted value, receiver should
         *        NOT modify it.
         */
        public void formatted(int fieldID, Format.Field attr, Object value,
                              int start, int end, StringBuffer buffer);
    }
}