1 package org.testng.annotations; 2 3 import static java.lang.annotation.ElementType.PARAMETER; 4 import static java.lang.annotation.RetentionPolicy.RUNTIME; 5 6 import org.testng.internal.Parameters; 7 8 import java.lang.annotation.Retention; 9 import java.lang.annotation.Target; 10 11 /** 12 * Specifies that the current parameter is optional. TestNG will pass 13 * in a specified default value, or <code>null</code> if none is specified. 14 */ 15 @Retention(RUNTIME) 16 @Target({PARAMETER}) 17 public @interface Optional { 18 /** The default value to pass to this parameter. <p>The default deserves 19 * a bit of explanation. JSR-175 (which defines annotations) says that 20 * Java annotation parameters can only be ConstantExpressions, which 21 * can be primitive/string literals, but not <code>null</code>.</p> 22 * <p>In this case, we use this string as a substitute 23 * for <code>null</code>; in practice, TestNG will pass <code>null</code> 24 * to your code, and not the string "null", if you do not specify 25 * a default value here in this parameter. 26 */ 27 public String value() default Parameters.NULL_VALUE; 28 } 29
