Generation of synthesized parameters (original) (raw)

Joe Darcy joe.darcy at oracle.com
Tue Jan 29 14:21:45 PST 2013

On 1/29/2013 2:06 PM, Peter Jensen wrote:

On 01/29/13 12:14, Joe Darcy wrote:

Hello,

On 1/29/2013 11:40 AM, Eric McCorkle wrote: In order to facilitate writing tests for the MethodParameters feature, I'd like to get a complete list of all the cases when javac can generate synthesized parameters.

Here is a list I've put together from email discussions and comments in JBS: 1) outer "this" parameters Arguably, some outer this parameters would be synthesized with others would be synthetic. Inner classes that are also member classes, (see diagram in "Nested, Inner, Member, and Top-Level Classes," https://blogs.oracle.com/darcy/entry/nestedinnermemberandtop), are potentially callable from outside of the enclosing class and are required to have an outer this parameter as the first parameter so that code from different compilers can call each other. The other this parameter in this case is synthesized as it is mandated or implied by the JLS. On the other hand, named inner classes defined inside a method or constructor as well as anonymous classes only need to obey a compiler-internal contract and any extra parameters in this case are synthetic. (Not all anonymous classes have an outer; an anonymous class created inside a static initializer block does not.)

2) extra values passed to constructor for enum values Such parameters are synthetic, they are a javac implementation artifact not mandated or implied by the JLS. 3) hidden values passed to constructors of inner classes for final variables You'll can check the JLS regarding whether these are synthesized or synthetic, but I would assume they are synthetic. 4) JLS mandated public no-arg constructors added by the compiler to classes with no declared constructor: synthesized This is not a parameter, but another language structure. HTH, -Joe 5) The two parameters pre-ended to enum constructors by javac

Does this capture everything, or does it miss something? Ideally, I would like to put together a complete list of all cases that should generate synthesized parameters. (If one already exists, then that's great). Thanks, Eric Argument pf synthetic enum valueOf() method. Synthetic or synthesized ?

The valueOf method itself is synthesized as the JLS mandates is creation, but I do not think the individual parameters of the method should be marked as such.

-Joe

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