### Question:
DhisFhirResourceId implements Serializable { public static boolean isValid( @Nullable String value ) { if ( value == null ) { return false; } try { parse( value ); } catch ( IllegalArgumentException e ) { return false; } return true; } DhisFhirResourceId( @Nullable DhisResourceType type, @Nonnull String id, @Nullable UUID ruleId );  DhisFhirResourceId( @Nonnull String id ); DhisResourceType getType(); @Nonnull String getId(); UUID getRuleId(); @Nonnull DhisResourceId getDhisResourceId(); boolean isQualified(); @Nonnull DhisFhirResourceId toQualified( @Nonnull DhisResourceType type, @Nonnull UUID ruleId ); @Override boolean equals( Object o ); @Override int hashCode(); @Override @Nonnull String toString(); @Nonnull static String toString( @Nullable DhisResourceType type, @Nonnull String id, @Nullable UUID ruleId ); static boolean isValid( @Nullable String value ); @Nonnull static DhisFhirResourceId parse( @Nonnull String value );  }### Answer:
@Test public void isValidNull() { Assert.assertFalse( DhisFhirResourceId.isValid( null ) ); }
@Test public void isValidNot() { Assert.assertFalse( DhisFhirResourceId.isValid( "abc-123" ) ); }
@Test public void isValid() { Assert.assertTrue( DhisFhirResourceId.isValid( "ldXIdLNUNEn" ) ); }