Comparing the value of a field

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tim@nocomment.com - 07 Jan 2007 21:26 GMT

If I want to change the value of the variable "count" using the
variable name "field_name" in the statement instead of "count", how do
I specify this?

String field_name = "count";

Instead of "count = 1;", I want to use something like
"field_name.valueOf() = 1:"

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Daniel Pitts - 07 Jan 2007 21:42 GMT

> If I want to change the value of the variable "count" using the
> variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 4 lines]
> Instead of "count = 1;", I want to use something like
> "field_name.valueOf() = 1:"

There isn't really an easy or good way to do this.
You can use Reflection, but its a lot slower, and easier to add bugs.
If you REALLY must do it, look up Class.getFields()

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Patricia Shanahan - 07 Jan 2007 22:02 GMT

It can be done, using reflection.

However, there are idioms in some languages that look like this, but are
better replaced by other Java features, not reflection.

What are you really trying to achieve? Why do you need this?

Patricia

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tim@nocomment.com - 07 Jan 2007 22:31 GMT

> > If I want to change the value of the variable "count" using the
> > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 11 lines]
>
> What are you really trying to achieve? Why do you need this?

I have a table that has user_id in one field and a list of fields
separated by a comma in another field. This cannot be changed or
redesigned! These fields are codes representing the fields that this
particular user can update.I want to put these fields into a Vector,
which I have already done, Then I want to iterate through the Vector
and use the fields as a key for a hash map which contains all of the
field codes and the actual field names. I will take these field names,
append an "_attr", which will be the name of that fields related
attribute field, and change the value from "readonly='true' to
readonly='false'.

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Daniel Pitts - 08 Jan 2007 01:00 GMT

> > > If I want to change the value of the variable "count" using the
> > > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 22 lines]
> attribute field, and change the value from "readonly='true' to
> readonly='false'.

Why not use a HashMap instead of a class?

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tim@nocomment.com - 08 Jan 2007 02:14 GMT

> > > > If I want to change the value of the variable "count" using the
> > > > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 24 lines]
>
> Why not use a HashMap instead of a class?

What do you mean?

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Daniel Pitts - 08 Jan 2007 17:58 GMT

> > > > > If I want to change the value of the variable "count" using the
> > > > > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 26 lines]
>
> What do you mean?

Why access the fields in a object at all? Why not just use a
HashMap<String, Boolean> that specifies what fields a user can read.
Better yet, have a Set<String> readOnlyFields = new HashSet<String>();

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tim@nocomment.com - 08 Jan 2007 20:01 GMT

> > > > > > If I want to change the value of the variable "count" using the
> > > > > > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 29 lines]
> HashMap<String, Boolean> that specifies what fields a user can read.
> Better yet, have a Set<String> readOnlyFields = new HashSet<String>();

Because that is the way it is set up.

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Daniel Pitts - 08 Jan 2007 21:00 GMT

> > > > > > > If I want to change the value of the variable "count" using the
> > > > > > > variable name "field_name" in the statement instead of "count", how do
[quoted text clipped - 31 lines]
>
> Because that is the way it is set up.

And you've carved the source code into stone?
Change the way its set up, thats what I'm saying.

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John Ersatznom - 08 Jan 2007 22:24 GMT

>>>>Why not use a HashMap instead of a class?
>>>
[quoted text clipped - 5 lines]
>
> Because that is the way it is set up.

With apologies to garbage men, uh I mean waste management personnel, and
environmentalists everywhere:

Reduce, Reuse, Refactor.

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Comparing the value of a field

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