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Grabbing an existing class's constructors?
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<span style="margin-bottom: 10px;">
created by <a href="https://community.jboss.org/people/mdale">Melissa Dale</a> in <i>Javassist</i> - <a href="https://community.jboss.org/message/818521#818521">View the full discussion</a>
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<div class="jive-rendered-content"><p><span style="color: #000000; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 17.14285659790039px; background-color: #ffffff;">I am a graduate student studying software engineering and technical debt. For my research I am using Javassist to create coupling between classes. However there is obviously a problem when I try to create an instance of a class that takes in parameters. I would really like to be able to grab a CtClass's initializers (if they're not an empty constructor), and then pass in the variables it is expecting. for example, consider I am trying to make an instance of class B in class A:</span><pre class="jive-pre"><code class="jive-code">
Public class B{public int foo;public char spam;public B(int bar, char eggs){    foo = bar;    spam = eggs;}
}
</code></pre><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p></p><pre class="jive-pre"><code class="jive-code">
Public class A{    B injected = new B(X,X);}
</code></pre><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="margin: 0 0 1em; font-size: 17.14285659790039px; background-color: #ffffff; color: #000000; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif;">currently I attempt to use a "isEmpty" check if the class initializer if it is not empty, in which case I have attempted the following two approaches. Both give me a 'no such constructor' error:</p><pre class="jive-pre"><code class="jive-code">
              if(from.getClassInitializer().isEmpty()){                       
                        String toBeAdded = from_class +" injected = new " + from_class+"();";
                        CtField f = CtField.make(toBeAdded, to);
                        to.addField(f);
                }
                //Hopefully this will catch cases where constructors are not empty and insert a dummy instructor
                else{
               }
</code></pre><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p><span style="color: #000000; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif; font-size: 17.14285659790039px; background-color: #ffffff;">I think the method "getClassInitializers" should return a CtClass's constructors as an array, but I'm unsure what to do with this array, which eclipse won't even let me declare. I'd like to loop through an array of expected parameters and make dummy variables of that type so I can do something like: </span><code style="padding: 1px 5px; background-color: #eeeeee; font-family: Consolas, Menlo, Monaco, 'Lucida Console', 'Liberation Mono', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', 'Courier New', monospace, serif;">B injected = new B (13, w);</code></p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="margin: 0 0 1em; font-size: 17.14285659790039px; background-color: #ffffff; color: #000000; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif;">Worse case scenario, I could create a blank class initializer in B so I could do <code style="padding: 1px 5px; background-color: #eeeeee; font-family: Consolas, Menlo, Monaco, 'Lucida Console', 'Liberation Mono', 'DejaVu Sans Mono', 'Bitstream Vera Sans Mono', 'Courier New', monospace, serif;">injected B = new B();</code> I think I should be able to use the makeClassInitializer() method, but that does not work for me, as I still get a no such constructor error. Something like:</p><pre class="jive-pre"><code class="jive-code">
               else{     
                        from.makeClassInitializer();
                        String toBeAdded = from_class + "injected = new " + from_class+"();";
                        CtField f = CtField.make(toBeAdded, to);
                        to.addField(f);
                }
</code></pre><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="margin: 0 0 1em; font-size: 17.14285659790039px; background-color: #ffffff; color: #000000; font-family: Arial, 'Liberation Sans', 'DejaVu Sans', sans-serif;">I would really appreciate any help or input you may have to offer. Thanks!</p></div>
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<p style="margin: 0;">Reply to this message by <a href="https://community.jboss.org/message/818521#818521">going to Community</a></p>
<p style="margin: 0;">Start a new discussion in Javassist at <a href="https://community.jboss.org/choose-container!input.jspa?contentType=1&containerType=14&container=2062">Community</a></p>
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