package org.relaxng.datatype;

/**
 * Datatype streaming validator.
 *
 * <p>
 * The streaming validator is an optional feature that is useful for
 * certain Datatypes. It allows the caller to incrementally provide
 * the literal.
 *
 * @author <a href="mailto:jjc@jclark.com">James Clark</a>
 * @author <a href="mailto:kohsuke.kawaguchi@sun.com">Kohsuke KAWAGUCHI</a>
 */
public interface DatatypeStreamingValidator {

        /**
         * Passes an additional fragment of the literal.
         *
         * <p>
         * The application can call this method several times, then call
         * the isValid method (or the checkValid method) to check the validity
         * of the accumulated characters.
         */
        void addCharacters( char[] buf, int start, int len );

        /**
         * Tells if the accumulated literal is valid with respect to
         * the underlying Datatype.
         *
         * @return
         *              True if it is valid. False if otherwise.
         */
        boolean isValid();

        /**
         * Similar to the isValid method, but this method throws
         * Exception (with possibly diagnostic information), instead of
         * returning false.
         *
         * @exception DatatypeException
         *              If the callee supports the diagnosis and the accumulated
         *              literal is invalid, then this exception that possibly
         *              contains diagnosis information is thrown.
         */
        void checkValid() throws DatatypeException;
}