001    package market;
002    
003    /**
004     * Implementations of this interface provide an easy way to check if a String complies with a special
005     * format.<br>
006     * If it doesn't, a ValueChecker can return a String describing the kind of error that was detected.
007     */
008    public interface ValueChecker extends java.io.Serializable {
009    
010        /**
011         *
012         * @param content the String to be tested
013         * @return <code>true</code> if the String is valid conforming with the particular ValueChecker's
014         * implementation, otherwise <code>false</code>.
015         */
016        boolean isValidValue(String content);
017    
018        /**
019         * @return a descriptive String depending on the kind of detected error
020         */
021        String getErrorString();
022    }