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PUT DATA

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  PUT DATA Roedy Green <see_website@mindprod.com.invalid> - 2013-02-08 14:21 -0800
    Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-08 17:34 -0500
      Re: PUT DATA Lew <lewbloch@gmail.com> - 2013-02-08 16:13 -0800
        Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-08 19:18 -0500
          Re: PUT DATA Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-08 20:44 -0400
            Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-08 19:52 -0500
              Re: PUT DATA Lew <lewbloch@gmail.com> - 2013-02-08 17:06 -0800
                Re: PUT DATA Lew <lewbloch@gmail.com> - 2013-02-08 17:08 -0800
                Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-08 20:09 -0500
                  Re: PUT DATA Lew <lewbloch@gmail.com> - 2013-02-08 17:16 -0800
                    Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-08 20:36 -0500
                      Re: PUT DATA Arved Sandstrom <asandstrom2@eastlink.ca> - 2013-02-09 08:14 -0400
    Re: PUT DATA Lew <lewbloch@gmail.com> - 2013-02-08 16:10 -0800
      Re: PUT DATA Roedy Green <see_website@mindprod.com.invalid> - 2013-02-09 09:54 -0800
    Re: PUT DATA Roedy Green <see_website@mindprod.com.invalid> - 2013-02-09 15:49 -0800
      Re: PUT DATA Arne Vajhøj <arne@vajhoej.dk> - 2013-02-09 19:21 -0500

#22211 — PUT DATA

In the olden days PL/I has a output mechanism called PUT DATA

Expresses Javesquely it would look like this:

out.putd ( xlow, xhigh);

It would output

xlow=23.4  xhigh=200.0

(There was also a keyword/value input method.  It was mainly helpful
in debugging.)
I could see how you could implement it in a preprocessor or
amanuensis, but can you do it with a pure Java method?  What if you
warp the syntax brutally to hide info with annotations?

-- 
Roedy Green Canadian Mind Products http://mindprod.com
The first 90% of the code accounts for the first 90% of the development time.
The remaining 10% of the code accounts for the other 90% of the development 
time. 
~ Tom Cargill  Ninety-ninety Law 

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#22212

On 2/8/2013 5:21 PM, Roedy Green wrote:
> In the olden days PL/I has a output mechanism called PUT DATA
>
> Expresses Javesquely it would look like this:
>
> out.putd ( xlow, xhigh);
>
> It would output
>
> xlow=23.4  xhigh=200.0
>
> (There was also a keyword/value input method.  It was mainly helpful
> in debugging.)
> I could see how you could implement it in a preprocessor or
> amanuensis, but can you do it with a pure Java method?  What if you
> warp the syntax brutally to hide info with annotations?

xlow and xhigh seems to be variable names.

They do not even exist at runtime for local variables.

So: no - impossible.

And annotations are put on types not on instances.

Arne

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#22216

Arne Vajhøj wrote:
>> And annotations are put on types not on instances.

http://docs.oracle.com/javase/7/docs/api/java/lang/annotation/ElementType.html
contradicts you.

How else would injection work?

-- 
Lew

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#22217

On 2/8/2013 7:13 PM, Lew wrote:
> Arne Vajhøj wrote:
>>> And annotations are put on types not on instances.
>
> http://docs.oracle.com/javase/7/docs/api/java/lang/annotation/ElementType.html
> contradicts you.
>
> How else would injection work?

????

X a;
X b;

what annotation are you suggesting that I use two distinguish between
the two X'es?

Arne

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#22220

On 02/08/2013 08:18 PM, Arne Vajhøj wrote:
> On 2/8/2013 7:13 PM, Lew wrote:
>> Arne Vajhøj wrote:
>>>> And annotations are put on types not on instances.
>>
>> http://docs.oracle.com/javase/7/docs/api/java/lang/annotation/ElementType.html
>>
>> contradicts you.
>>
>> How else would injection work?
>
> ????
>
> X a;
> X b;
>
> what annotation are you suggesting that I use two distinguish between
> the two X'es?
>
> Arne
>
This suddenly got confusing. I believe we all know that we can have one 
set of annotations on

X a;

and a completely different set of annotations on

X b;

Clearly the annotations must be appropriate for type 'X', but they are 
separately associated to 'a' and to 'b'.

AHS

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#22223

On 2/8/2013 7:44 PM, Arved Sandstrom wrote:
> On 02/08/2013 08:18 PM, Arne Vajhøj wrote:
>> On 2/8/2013 7:13 PM, Lew wrote:
>>> Arne Vajhøj wrote:
>>>>> And annotations are put on types not on instances.
>>>
>>> http://docs.oracle.com/javase/7/docs/api/java/lang/annotation/ElementType.html
>>>
>>>
>>> contradicts you.
>>>
>>> How else would injection work?
>>
>> ????
>>
>> X a;
>> X b;
>>
>> what annotation are you suggesting that I use two distinguish between
>> the two X'es?
>>
> This suddenly got confusing. I believe we all know that we can have one
> set of annotations on
>
> X a;
>
> and a completely different set of annotations on
>
> X b;
>
> Clearly the annotations must be appropriate for type 'X', but they are
> separately associated to 'a' and to 'b'.

Maybe I am the only one in the known universe that don't know.

But let us say we have:

X a = new X(aa);
X b = new X(bb);
test(a,b);

void test(X a,X b) {
}

How should the annotation look like, how should it be put on and
how do I get it in test?

I know how to put an annotation on the type X that I can get in
test. But that is the same for both a and b. Roedy needs a
different annotation (value).

I don't think I have ever seen that done with instances.

Arne

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#22226

Arne Vajhøj wrote:
> Maybe I am the only one in the known universe that don't know.
> 
> But let us say we have:
> 
> X a = new X(aa);
> X b = new X(bb);
> 
> test(a,b);
> 
> void test(X a,X b) {
> 
> }
> 
> How should the annotation look like, how should it be put on and
> how do I get it in test?

I don't understand your question "How do I get it in test?"

> I know how to put an annotation on the type X that I can get in
> test. But that is the same for both a and b. Roedy needs a
> different annotation (value).
>
> I don't think I have ever seen that done with instances.

Take a look at JPA:

@Column(name="SURNAME")
private String lastName;

@Column(name="GIVENNAME")
private String firstName;

Is that not annotating a field? And annotations can annotate a local variable, too.

It's not annotating 'String'.

Is that not what you wanted?

-- 
Lew

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#22228

Lew wrote:
> Arne Vajhøj wrote:
>> Maybe I am the only one in the known universe that don't know.
> 
>> But let us say we have:
> 
>> X a = new X(aa);
>> X b = new X(bb);
> 
>> test(a,b);
> 
>> void test(X a,X b) {
>> }
>> 
>> How should the annotation look like, how should it be put on and
>> how do I get it in test?
> 
> I don't understand your question "How do I get it in test?"
> 
>> I know how to put an annotation on the type X that I can get in
>> test. But that is the same for both a and b. Roedy needs a
>> different annotation (value).
> 
>> I don't think I have ever seen that done with instances.
> 
> Take a look at JPA:
> 
> @Column(name="SURNAME")
> private String lastName;
> 
> @Column(name="GIVENNAME")
> private String firstName;
> 
> Is that not annotating a field? And annotations can annotate a local variable, too.
> 
> It's not annotating 'String'.
> 
> Is that not what you wanted?

public void test( @Nullable Foo x, @NotNull Bar y)
{ ... }

-- 
Lew

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#22229

On 2/8/2013 8:06 PM, Lew wrote:
> Arne Vajhøj wrote:
>> Maybe I am the only one in the known universe that don't know.
>>
>> But let us say we have:
>>
>> X a = new X(aa);
>> X b = new X(bb);
>>
>> test(a,b);
>>
>> void test(X a,X b) {
>>
>> }
>>
>> How should the annotation look like, how should it be put on and
>> how do I get it in test?
>
> I don't understand your question "How do I get it in test?"

How do I inside the test method retrieve the different
annotations on a an b?

>> I know how to put an annotation on the type X that I can get in
>> test. But that is the same for both a and b. Roedy needs a
>> different annotation (value).
>>
>> I don't think I have ever seen that done with instances.
>
> Take a look at JPA:
>
> @Column(name="SURNAME")
> private String lastName;
>
> @Column(name="GIVENNAME")
> private String firstName;
>
> Is that not annotating a field? And annotations can annotate a local variable, too.
>
> It's not annotating 'String'.
>
> Is that not what you wanted?

Not unless one can call a method with firstName and lastName and
inside that method retrieve the two column names.

Arne

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#22231

Arne Vajhøj wrote:
> Lew wrote:
>> Arne Vajh�j wrote:
>>> Maybe I am the only one in the known universe that don't know.
> 
>>> But let us say we have:
> 
>>> X a = new X(aa);
>>> X b = new X(bb);
>>> test(a,b);
>>> void test(X a,X b) {
>>> }
>>> How should the annotation look like, how should it be put on and
>>> how do I get it in test?
> 
>> I don't understand your question "How do I get it in test?"
> 
> How do I inside the test method retrieve the different
> annotations on a an b?

>>> I know how to put an annotation on the type X that I can get in
>>> test. But that is the same for both a and b. Roedy needs a
>>> different annotation (value).
>>>
>>> I don't think I have ever seen that done with instances.
> 
>> Take a look at JPA:
> 
>> @Column(name="SURNAME")
>> private String lastName;
>>
>> @Column(name="GIVENNAME")
>> private String firstName;
>>
>> Is that not annotating a field? And annotations can annotate a local variable, too.
>>
>> It's not annotating 'String'.
>>
>> Is that not what you wanted?
> 
> Not unless one can call a method with firstName and lastName and
> inside that method retrieve the two column names.

You retrieve annotations via reflection, but that is neither relevant to what I was answering 
nor something you normally want to do.

I was answering your assertions that annotations only apply to a type. That's just wrong.
Clearly you can annotate fields, local variables, constructors, methods, ...

Annotations are METAprogramming. They're handled outside the code that is annotated. By other code.

You don't retrieve the annotations inside the method. You get other behavior, like automagically 
having a connection to the correct table element. SO THAT YOU DON'T HAVE TO RETRIEVE IT.
That's the whole point of having the annotation. If you want to retrieve the value, don't use annotations.

Or with @NonNull you might get compiler-time explosion over a possibility that the variable could be 
null, or a runtime error if it is without having to explicitly code for it. Again, the point is you do the 
annotation so the code inside the method doesn't have to deal with it.

Use annotations correctly and your question vanishes. Your assertion that annotations only apply to 
types is already wrong.

-- 
Lew

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#22235

On 2/8/2013 8:16 PM, Lew wrote:
> Arne Vajhøj wrote:
>> Lew wrote:
>>> Arne Vajh�j wrote:
>>>> Maybe I am the only one in the known universe that don't know.
>>
>>>> But let us say we have:
>>
>>>> X a = new X(aa);
>>>> X b = new X(bb);
>>>> test(a,b);
>>>> void test(X a,X b) {
>>>> }
>>>> How should the annotation look like, how should it be put on and
>>>> how do I get it in test?
>>
>>> I don't understand your question "How do I get it in test?"
>>
>> How do I inside the test method retrieve the different
>> annotations on a an b?
>
>>>> I know how to put an annotation on the type X that I can get in
>>>> test. But that is the same for both a and b. Roedy needs a
>>>> different annotation (value).
>>>>
>>>> I don't think I have ever seen that done with instances.
>>
>>> Take a look at JPA:
>>
>>> @Column(name="SURNAME")
>>> private String lastName;
>>>
>>> @Column(name="GIVENNAME")
>>> private String firstName;
>>>
>>> Is that not annotating a field? And annotations can annotate a local variable, too.
>>>
>>> It's not annotating 'String'.
>>>
>>> Is that not what you wanted?
>>
>> Not unless one can call a method with firstName and lastName and
>> inside that method retrieve the two column names.
>
> You retrieve annotations via reflection

In this case?

>                                       , but that is neither relevant to what I was answering
> nor something you normally want to do.
>
> I was answering your assertions that annotations only apply to a type. That's just wrong.
> Clearly you can annotate fields, local variables, constructors, methods, ...
>
> Annotations are METAprogramming. They're handled outside the code that is annotated. By other code.
>
> You don't retrieve the annotations inside the method. You get other behavior, like automagically
> having a connection to the correct table element. SO THAT YOU DON'T HAVE TO RETRIEVE IT.
> That's the whole point of having the annotation. If you want to retrieve the value, don't use annotations.
>
> Or with @NonNull you might get compiler-time explosion over a possibility that the variable could be
> null, or a runtime error if it is without having to explicitly code for it. Again, the point is you do the
> annotation so the code inside the method doesn't have to deal with it.
>
> Use annotations correctly and your question vanishes. Your assertion that annotations only apply to
> types is already wrong.

Maybe you should read the context.

I answered a question whether annotations could solve a specific problem.

For annotations to solve that problem they would need to be applied
to instances similar to how it can be done for types.

All the stuff you list are utterly irrelevant for the question asked.

Arne

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#22250

On 02/08/2013 09:36 PM, Arne Vajhøj wrote:
[ SNIP ]

>
> Maybe you should read the context.
>
> I answered a question whether annotations could solve a specific problem.
>
> For annotations to solve that problem they would need to be applied
> to instances similar to how it can be done for types.
>
> All the stuff you list are utterly irrelevant for the question asked.
>
> Arne
>
I think the best bet here is to wait for JDK 8. JEP 118, which appears 
to still be in play, is for exactly this.

I just now tried this out with the latest build, and it looks like they 
are working on it. You can get a list of parameters on a Method, as 
instances of class java.lang.reflect.Parameter, and there is a method 
getName() in the Parameter class.

Unfortunately right now it still prints out values like 'arg0' and 
'arg1', regardless of the actual names, but the idea is there.

AHS

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#22214

Roedy Green wrote:
> In the olden days PL/I has a output mechanism called PUT DATA
> 
> Expresses Javesquely it would look like this:
> 
> out.putd ( xlow, xhigh);
> 
> It would output
> 
> xlow=23.4  xhigh=200.0
> 
> (There was also a keyword/value input method.  It was mainly helpful
> in debugging.)
> 
> I could see how you could implement it in a preprocessor or
> amanuensis, but can you do it with a pure Java method?  

What do you mean by "amanuensis"?

-- 
Lew

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#22251

On Fri, 8 Feb 2013 16:10:48 -0800 (PST), Lew <lewbloch@gmail.com>
wrote, quoted or indirectly quoted someone who said :

>
>What do you mean by "amanuensis"?

see http://mindprod.com/jgloss/amanuensis.html




-- 
Roedy Green Canadian Mind Products http://mindprod.com
The first 90% of the code accounts for the first 90% of the development time.
The remaining 10% of the code accounts for the other 90% of the development 
time. 
~ Tom Cargill  Ninety-ninety Law 

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#22256

On Fri, 08 Feb 2013 14:21:50 -0800, Roedy Green
<see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted
someone who said :

>In the olden days PL/I has a output mechanism called PUT DATA

I have written this up as a beginner student project at

http://mindprod/project/putdata.html
-- 
Roedy Green Canadian Mind Products http://mindprod.com
The first 90% of the code accounts for the first 90% of the development time.
The remaining 10% of the code accounts for the other 90% of the development 
time. 
~ Tom Cargill  Ninety-ninety Law 

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#22257

On 2/9/2013 6:49 PM, Roedy Green wrote:
> On Fri, 08 Feb 2013 14:21:50 -0800, Roedy Green
> <see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted
> someone who said :
>> In the olden days PL/I has a output mechanism called PUT DATA
>
> I have written this up as a beginner student project at
>
> http://mindprod/project/putdata.html

Today the feature is probably more common seen in C/C++.

With something like:

#define PRINTD(x) printf("%s=%d\n", #x, x)
#define PRINTS(x) printf("%s=%s\n", #x, x)

Arne

PS: I know that I can do:

#define PRINTD(x) printf(#x "=%d\n", x)
#define PRINTS(x) printf(#x "=%s\n", x)

but it just doesn't seem as readable to me.

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