empty string

To whom it concerns,





I have written a plugin (My_logPlugin) which extends the logPPlugin class. In the licenses.dat file which is stored at /root/.chemaxon I added the following:





chemaxon.marvin.calculations.My_logPlugin=27071966





In my class My_logPlugin I havethe code





My_logPlugin x = new My_logPlugin();





System.out.println("License key for My_logPlugin is :");


System.out.println(x.getLicenseKey());





But, I get an empty string returned instead of 27071966.





Could you please advise me as to what I'm doing wrong? Do I need a specific license key from ChemAxon for each of my own Plugins?





Kind regards,


Miriam

This below applies to the current Marvin release, it will be much simpler in the next release (4.0.2).





First of all: you set the plugin license key within the code by overriding

Code:

plugin.getLicenseKey()

as written in


http://www.chemaxon.com/marvin/doc/dev/plugins.html


and users set the key in the licenses.dat file which will be checked against the hard-coded license key.





Unfortunately if you extend an existing plugin class then you cannot change its license key, since the method plugin.getLicenseKey() is declared final for safety reasons.


To validate a plugin you should call

Code:

plugin.validate(<license key>);

It is only after this call that the

Code:

plugin.getLicenseKey()

method returns the real license key instead of the empty string.





However, as I have mentioned, the current implementation makes it impossible to subclass a plugin and change its license key (this would be possible by overriding its


getLicenseKey() method which is final) - since in this case it would be possible to


subclass a plugin only to change its license key.





The good news is that I have changed this mechanism - from the next release (4.0.2)


you should only override the

Code:

plugin.validate(<license key>)

by a simple string comparison with the real key - but this validate() is still declared final for safety (otherwise someone could just subclass the plugin and change its validate() method only). I will think about a solution for this problem.





In the meantime, if you want to write a custom logP plugin with a separate license key then unfortunately you should subclass CalculatorPlugin directly and implement the getLicenseKey() (or validate() from the next rellease()) as written in


http://www.chemaxon.com/marvin/doc/dev/plugins.html





Then you can write code like:

Code:

My_logPlugin x = new My_logPlugin(); x.validate("27071966"); System.out.println("License key for My_logPlugin is :"); System.out.println(x.getLicenseKey());

Then you will get "27071966" instead of the empty string.





PS: I will ask the approximate date for the Marvin 4.0.2 tomorrow.

Nora wrote:

The good news is that I have changed this mechanism - from the next release (4.0.2) you should only override the Code: plugin.validate(<license key>) by a simple string comparison with the real key - but this validate() is still declared final for safety (otherwise someone could just subclass the plugin and change its validate() method only). I will think about a solution for this problem.

I have implemented a somewhat tricky solution:

Code:

plugin.validate(String license)

is no longer required to be declared final, and all superclasses' license keys are checked by the plugin handling mechanism.





This means that if you extend a plugin then your plugin will automatically require the license keys for all superclasses. You can add a specific license key by implementing

Code:

plugin.validate(String license)

For example:

Code:

public class My_logPPlugin extends logPPlugin {     public boolean validate(String license) {         return "12345678".equals(license);     } }

This will set the plugin license key to "12345678" while the logPPlugin license is also required. You should set these two license keys in the licenses.dat file.





Marvin 4.0.2 release: there will be a test-release this week, the precise date of the final 4.0.2 release is not known yet, probably next week.

Hi Nora,





Thanks for all your help on the license issue. I would like to be able to use the classes Mass and MolHandler. But, I can't find them. Would it be possible for you to send them to me?








Regards,


Miiram

MolHandler is part of JChem, not Marvin:


http://www.chemaxon.com/jchem/doc/api/chemaxon/util/MolHandler.html


You should download JChem:


http://www.chemaxon.com/jchem/


to use it. If you only need this class for molecule import then you can just as well use


MolImporter:


http://www.chemaxon.com/marvin/doc/api/chemaxon/formats/MolImporter.html


which is part of Marvin.





Also the class Mass is part of JChem:


http://www.chemaxon.com/jchem/doc/api/chemaxon/descriptors/scalars/Mass.html


but this is a scalar descriptor used in molecular similarity calculations.


If you simply need to compute the molecular mass then use





MoleculeGraph.getMass()

A pre-released Marvin 4.0.2 (test version) can be downloaded from:


http://www.chemaxon.com/test/marvin/