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visitor derivation

introduction

This is an example where we define MyMemReleaser by deriving MemReleaser, an existing X3DProcessor which deletes the default X3DNodes and X3DGLNodes. We want here to print the name of the nodes deleted.

deriving MemReleaserAbstractVisitor

The name of the node is an attribute of X3DAbstractNode, so we only need to define the function enterX3DAbstractNode of a AbstractVisitor called MyMemReleaserAbstractVisitor. We also add the definition of an enterCylinder function to show the validation of functions. Cylinder doesn't belong to the Abstract component, so there will be an error message.

deriving MemReleaser

We derive the X3DProcessor MemReleaser in MyMemReleaser. We have then to plug MyMemReleaserAbstractVisitor to MyMemReleaser in the constructor.

code

MyMemReleaserAbstractVisitor.h

//                            MyMemReleaserAbstractVisitor.h                  //

#ifndef MYMEMRELEASERABSTRACTVISITOR_H
#define MYMEMRELEASERABSTRACTVISITOR_H

#include <X3DTK/kernel.h>

namespace X3DTK {

// Visitor for the Abstract component of the MemReleaser module.

class MyMemReleaserAbstractVisitor : public MemReleaserAbstractVisitor
{
public:
  // Constructor.
  MyMemReleaserAbstractVisitor();

  // Enters an X3DAbstractNode.
  virtual void enterX3DAbstractNode(X3DAbstractNode *N) const;
  // Enters a Cylinder.
  virtual void enterCylinder(X3D::Cylinder *C) const;
};

}

#endif

MyMemReleaserAbstractVisitor.cpp

#include "MyMemReleaserAbstractVisitor.h"

#include <iostream>

using namespace X3DTK;
using namespace std;

MyMemReleaserAbstractVisitor::MyMemReleaserAbstractVisitor()
: MemReleaserAbstractVisitor()
{
  // Defines the new enter function for the X3DAbstractNode.
  defineNewEnterFunction<MyMemReleaserAbstractVisitor, X3DAbstractNode>(&MyMemReleaserAbstractVisitor::enterX3DAbstractNode);
  // Defines the new enter function for the Cylinder. This method will not be recorded 
  // because Cylinder doesn't belong to the Abstract component.
  defineNewEnterFunction<MyMemReleaserAbstractVisitor, X3D::Cylinder>(&MyMemReleaserAbstractVisitor::enterCylinder);
}

void MyMemReleaserAbstractVisitor::enterX3DAbstractNode(X3DAbstractNode *N) const
{
  // Prints the name of the node.
  cout << N->getTypeName() << " released " << endl;
  MemReleaserAbstractVisitor::enterX3DAbstractNode(N);
}

void MyMemReleaserAbstractVisitor::enterCylinder(X3D::Cylinder *C) const
{
  // empty because it will never be called.
}

MyMemReleaser.h

//                            MyMemReleaser.h                                 //

#ifndef MYMEMRELEASER_H
#define MYMEMRELEASER_H

#include <X3DTK/kernel.h>

namespace X3DTK {

// Class deriving MemReleaser.

class MyMemReleaser : public MemReleaser
{
public:
  // Constructor.
  MyMemReleaser();
};

}

#endif

MyMemReleaser.cpp

#include "MyMemReleaser.h"
#include "MyMemReleaserAbstractVisitor.h"

#include <iostream>

using namespace std;
using namespace X3DTK;

MyMemReleaser::MyMemReleaser()
: MemReleaser()
{
  // Sets the Root visitor for MyMemReleaser processor.
  setComponentVisitor(new MyMemReleaserAbstractVisitor());
}

main.cpp

#include "MyMemReleaser.h"
#include <X3DTK/kernel.h>
#include <iostream>

using namespace X3DTK;
using namespace std;

int main(int argc, char *argv[])
{
  if (argc <= 1)
  {
    cerr << "usage: mymemreleaser input" << endl;
    exit(0);
  }
  
  // DefaultLoader to load the default X3D Nodes.
  X3DLoader *loader = new DefaultLoader();
  // Instanciation of the new MemReleaser.
  MemReleaser *releaser = new MyMemReleaser();
  
  // Loads the scene.
  X3D::Scene *s = loader->load(argv[1]);
  // Releases the memory.
  releaser->release(s);
      
  return 1;
}

Generated on Tue Jul 15 16:46:54 2003 for X3DToolKit by doxygen1.3