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Content-MD5: DRDEqmiYF1BcrcIV1rHCqg==
Message-ID:  <[log in to unmask]>
Date:         Thu, 21 Sep 2000 12:45:28 -0400
Reply-To:     Ping Tan <[log in to unmask]>
Sender:       ImageJ Interest Group <[log in to unmask]>
From:         Ping Tan <[log in to unmask]>
Subject:      Interface,parameters...

Dear Wayne,
   I am a new user of ImageJ, and I am trying to understand your program's
structure and logic before I can utilize your wonderful program. I have some
questions to ask, please help me if you have time.

   In method runUserPlugin(), there are some code like the following:

      thePlugin = (loader.loadClass(className)).newInstance();
      if(thePlugin instance of Plugin)
         ((Plugin)thePlugin).run(arg);
          ..................

   1). According to the source code of class PluginClassLoad (I downloaded
       your v.118), there should be 2 parameters instead of just one in the
              loadClass(Sting name, boolean resolve)
       method, and you don't have any override method for this one. One
       parameter is missing, how does it work?
   2). Plugin is defined as an interface, it  has one abstract method run().
       Many classes implements this Plugin interface, such as class DICOM.
       As a class, DICOM extends from ImagePlus and implements Plugin,
       (loader.loadClass(className)) will return a class c, if the className
       is "ij.plugin.DICOM", the returned c should be DICOM.class, when it is
       new by newInstance() we will have an instance of class DICOM,then how
       does the JVM knows that it should be a subclass of ImagePlus or an
       implementor of Plugin (maybe both) when your call
                 if(thePlugin instance of Plugin)?

   3). Another question related with 2) is (sorry I am new for Java also):
       when you call loadit(calssname) in PluginClassLoader, the very last
       statement is :
          return defineClass(classname, buf, buf.length);
       here the classname is something like "ij.plugin.DICOM", how does the
       compiler match it with "DICOM"? In other words, statement
          loader.loadClass(className)
       will return ij.plugin.DICOM or DICOM?

    Thanks in advance for your help!

Ping Tan, Ph.D.
Medical Engineering Department
Radiology Department
Wake Forest University, School of Medicine
Medical Center BLVD
Winston-Salem, NC 27157, USA
(phone) 336-716-2704
(fax)   336-716-2870
e_mail  [log in to unmask]

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