/*
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 * and open the template in the editor.
 */

package dynaclasstest;

import java.io.IOException;
import java.security.SecureClassLoader;
import javax.tools.Diagnostic.Kind;
import javax.tools.FileObject;
import javax.tools.ForwardingJavaFileManager;
import javax.tools.JavaFileManager.Location;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;

/**
 *
 * @author dhaval
 */
public class ClassFileManager extends ForwardingJavaFileManager{

    /**
    * Instance of JavaClassObject that will store the
    * compiled bytecode of our class
    */
    private JavaClassObject jclassObject;

    /**
    * Will initialize the manager with the specified
    * standard java file manager
    *
    * @param standardManger
    */
    public ClassFileManager(StandardJavaFileManager
        standardManager) {
        super(standardManager);
    }

    /**
    * Will be used by us to get the class loader for our
    * compiled class. It creates an anonymous class
    * extending the SecureClassLoader which uses the
    * byte code created by the compiler and stored in
    * the JavaClassObject, and returns the Class for it
    */
    @Override
    public ClassLoader getClassLoader(Location location) {
        return new SecureClassLoader() {
            @Override
            protected Class<?> findClass(String name)
                throws ClassNotFoundException {
                byte[] b = jclassObject.getBytes();
                return super.defineClass(name, jclassObject
                    .getBytes(), 0, b.length);
            }
        };
    }

    /**
    * Gives the compiler an instance of the JavaClassObject
    * so that the compiler can write the byte code into it.
    */
    @Override
    public JavaFileObject getJavaFileForOutput(Location location,
        String className, JavaFileObject.Kind kind, FileObject sibling)
            throws IOException {
            jclassObject = new JavaClassObject(className, kind);
        return jclassObject;
    }
}