package javax.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

import javax.annotation.meta.TypeQualifier;
import javax.annotation.meta.When;

/**
 * This annotation a value that is of a particular syntax, such as Java syntax
 * or regular expression syntax. This can be used to provide syntax checking of
 * constant values at compile time, run time checking at runtime, and can assist
 * IDEs in deciding how to interpret String constants (e.g., should a
 * refactoring that renames method {@code x()} to {@code y()}
 * update the String constant {@code "x()"}).
 */
@Documented
@TypeQualifier(applicableTo = CharSequence.class)
@Retention(RetentionPolicy.RUNTIME)
public @interface Syntax {
    /**
     * Value indicating the particular syntax denoted by this annotation.
     * Different tools will recognize different syntaxes, but some proposed
     * canonical values are:
     * <ul>
     * <li> "Java"
     * <li> "RegEx"
     * <li> "JavaScript"
     * <li> "Ruby"
     * <li> "Groovy"
     * <li> "SQL"
     * <li> "FormatString"
     * </ul>
     * <p>
     * Syntax names can be followed by a colon and a list of key value pairs,
     * separated by commas. For example, "SQL:dialect=Oracle,version=2.3". Tools
     * should ignore any keys they don't recognize.
     *
     * @return a name indicating the particular syntax.
     */
    String value();

    When when() default When.ALWAYS;
}
