Re: JRuby Cookbook example 1.10

>
> One last thing I should mention is that I created this as a netbeans Java
> Application. I assume that this is the correct project type. I actually
> created two of these Java Application projects - one simply defaulted to
> JavaApplication1 and one named PrintJavaClass.
>
> There are other project types including Java Desktop Application  and Java
> Class Library and Java Free-Forn Project.
>
> Perhaps I should have named the project
> org\jrubycookbook\ch01\PrintJavaClass

>
>
> cag wrote:
>>
>> Thank you Yoko for the careful evaluation and reply to my questions.
>> I think the one thing that I might be missing in all this is where you got
>> the JARs or sample code for the solution. I am reading this book though my
>> Safari books subscription and can not find the chapter based sample code
>> nor the code implementing "PrintJavaClass".
>>
>> Did you have sample code or create your own "PrintJavaClass"? Did you
>> obtain any sample code for each chapter?
>> If it is case that I simple need to create  a package called
>> org\jrubycookbook\ch01\PrintJavaClass.java I guess I have a lot to learn
>> about creating "empty/new" package paths. Perhaps you would be kind enough
>> to show me the correct way to create the package org\jrubycookbook\ch01.
>>
>>
>>
>>
>>
>> Yoko Harada wrote:
>>>
>>> Hi,
>>>
>>> On Mon, Jun 29, 2009 at 10:41 PM, cag<cagraff@...> wrote:
>>>>
>>>> I can not seem to get Example 1.10 to work using Netbeans 6.51 or 6.7. I
>>>> create a Java Application project in Netbeans and pasted the code from
>>>> the
>>>> book in verbatim.
>>>
>>> This sample worked as far as I tried although the output was bit
>>> different shown in the book.
>>>
>>>>
>>>> I was finally able to resolve org.jruby.Ruby by specifically adding
>>>>  C:\Program Files\NetBeans 6.7\ruby2\jruby-1.2.0\lib\jruby.jar
>>>> to the library options for the project - not ideal I think but it works
>>>
>>> You did in a very common way as described at
>>> http://www.netbeans.org/kb/docs/java/project-setup.html#projects-classpath.
>>>
>>>>
>>>> But that still left me with these errors:
>>>>
>>>> package org.jrubycookbook.ch01;  // incorrect package name - also, is
>>>> this
>>>> perhaps where PrintJavaClass should reside?
>>>
>>> Package hierarchies are mapped to directory(folder) hierarchies. The
>>> example has org.jrubyvookbook.ch01 for its package name, so
>>> PrintJavaClass.java file must reside under the org\jrubycookbook\ch01
>>> directory. Probably,
>>> http://java.sun.com/docs/books/tutorial/java/package/managingfiles.html
>>> would help you to figure out what the package is.
>>> Since you are using NetBeans, you don't need to create folders by
>>> hand. http://www.netbeans.org/kb/docs/java/javase-intro.html might be
>>> good for you.
>>>
>>>>
>>>> public class PrintJavaClass // PrintJavaClass is public, it should be
>>>> declared in a file named PrintJavaClass.java
>>>
>>> Yes. Public classes should be in the same filenames, so your program
>>> should be written in org\jrubycookbook\ch01\PrintJavaClass.java. You
>>> can found a lot of information by googling since this is a basic part
>>> of Java.
>>>
>>>>
>>>> List<Class> interfaces = Arrays.asList(o.getClass().getInterfaces()); //
>>>> Incompatible types required java.util.List<java.lang.Class> found
>>>> java.util.List<java.lang.Class<?>>
>>>
>>> I'm not sure why you got this error. The error might be resolved if
>>> you could set up your Java project correctly on NetBeans.
>>>
>>> -Yoko
>>>
>>>>
>>>>
>>>> What environment where you using where you didn't get these errors?
>>>>
>>>>
>>>> Carl Graff wrote:
>>>>>
>>>>> Actually I did find instances of the jruby.jar but I think for some
>>>>> reason
>>>>> these are not considered path of the default classpath
>>>>>
>>>>> C:\Program Files\NetBeans
>>>>> 6.7\ruby2\jruby-1.2.0\lib\jruby.jar\org\jruby\Ruby.class
>>>>> C:\Program Files\NetBeans
>>>>> 6.5\ruby2\jruby-1.1.6\lib\jruby.jar\org\jruby\
>>>>> Ruby.class
>>>>>
>>>>> Carl Graff wrote:
>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Unfortunately I only got to example 1.10 before getting stuck. I have
>>>>>> used both Ruby and Java for several years but it is a little
>>>>>> disheartening to get bogged down this early in the book.
>>>>>>
>>>>>> The sample code is below and here are some of my questions about it:
>>>>>> 1. Most importantly is is choking on
>>>>>> import org.jruby.Ruby;
>>>>>> I found a jruby.Jar on the JRuby site but I am using a complete
>>>>>> Netbeans
>>>>>> 6.7 download (Java and Ruby) and also tried adding Ruby and JRuby
>>>>>> plugins
>>>>>> to a 6.5 build. Nether of these builds know what to do with
>>>>>> import org.jruby.Ruby;
>>>>>> Do I need to download JRuby code - in addition - to the JRuby code and
>>>>>> libraries provided by NetBeans? If so do I need to put this code in a
>>>>>> special directory or add an environment setting or a netbeans option
>>>>>> so
>>>>>> it get recognized?
>>>>>>
>>>>>>
>>>>>> 2. The statement
>>>>>> package org.jrubycookbook.ch01;  Leads me to believe that either I
>>>>>> need
>>>>>> to download some associated sample programs or libraries or the I need
>>>>>> to
>>>>>> put this code in a specific directory relative to netbeans or perhaps
>>>>>> relative to a separate installation of JRuby if that is needed - is
>>>>>> either of these statements correct? If I need to download sample code
>>>>>> or
>>>>>> libraries the book does not seem to have a link to a download area.
>>>>>>
>>>>>> 3. The text preceding the sample indicates
>>>>>> Ruby Array objects can also be coerced into Java Array objects by
>>>>>> calling
>>>>>> the to_java method. Example 1-10
>>>>>> <javascript:moveTo('ruby_to_java_type_conversion');> includes a
>>>>>> combination of Java and Ruby code, which demonstrates this
>>>>>> functionality.
>>>>>> But I see no call to "to_java" in the sample code.
>>>>>>
>>>>>> package org.jrubycookbook.ch01;
>>>>>>
>>>>>> import java.io.PrintWriter;
>>>>>> import java.io.StringWriter;
>>>>>> import java.util.Arrays;
>>>>>> import java.util.Collections;
>>>>>> import java.util.List;
>>>>>>
>>>>>> import org.jruby.Ruby;
>>>>>> import org.jruby.javasupport.JavaEmbedUtils;
>>>>>>
>>>>>> public class PrintJavaClass {
>>>>>>
>>>>>>    // Output the class and interface list for a single object
>>>>>>    public String output(Object o) {
>>>>>>        String className = o.getClass().getName();
>>>>>>        List<Class> interfaces =
>>>>>> Arrays.asList(o.getClass().getInterfaces());
>>>>>>
>>>>>>        return String.format("%s, implements %s\n", className,
>>>>>> interfaces);
>>>>>>    }
>>>>>>
>>>>>>    // Output the class and interface list for each object in an array
>>>>>>    public String output(Object[] objects) {
>>>>>>        PrintWriter writer = new PrintWriter(new StringWriter());
>>>>>>        for (Object o : objects) {
>>>>>>            String className = o.getClass().getName();
>>>>>>            List<Class> interfaces = Arrays
>>>>>>                    .asList(o.getClass().getInterfaces());
>>>>>>
>>>>>>            writer.printf("%s (inside array), implements %s\n",
>>>>>> className,
>>>>>>                    interfaces);
>>>>>>        }
>>>>>>        return writer.toString();
>>>>>>    }
>>>>>>
>>>>>>    public static void main(String[] args) {
>>>>>>        Ruby runtime =
>>>>>> JavaEmbedUtils.initialize(Collections.EMPTY_LIST);
>>>>>>        String script = "@printer =
>>>>>> org.jrubycookbook.ch01.PrintJavaClass.new\n"
>>>>>>                + "def output(o)\n"
>>>>>>                + "puts \"#{o.to_s} - #{@printer.output(o)}\"\n"
>>>>>>                + "end\n"
>>>>>>                + "output(1)\n"
>>>>>>                + "output(0.5)\n"
>>>>>>                + "output('string')\n"
>>>>>>                + "output(true)\n"
>>>>>>                + "output([4, 8, 15, 16, 23, 42])\n"
>>>>>>                + "output([4, 8, 15, 16, 23, 42].to_java)\n"
>>>>>>                + "output({ 'NY' => 'New York', 'MA' =>
>>>>>> 'Massachusetts'})\n";
>>>>>>
>>>>>>        runtime.evalScriptlet(script);
>>>>>>        JavaEmbedUtils.terminate(runtime);
>>>>>>    }
>>>>>> }
>>>>
>>>>
>>>>
>>>> --
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>>>> Sent from the JRuby - User mailing list archive at Nabble.com.
>>>>
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