77 lines
2.9 KiB
Plaintext
77 lines
2.9 KiB
Plaintext
#ifndef OSG_OBJECT
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#define OSG_OBJECT 1
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#include <osg/Referenced>
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namespace osg {
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class Input;
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class Output;
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/** Base class/standard interface for objects which require IO support,
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cloning and reference counting.
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Based on GOF Composite, Prototype and Template Method patterns.
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*/
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class SG_EXPORT Object : public Referenced
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{
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public:
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/** Construct an object. Note Object is a pure virtual base class
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and therefore cannot be constructed on its own, only derived
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classes which overide the clone and className methods are
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concrete classes and can be constructed.*/
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Object() {}
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/** return a shallow copy of a node, with Object* return type.
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Must be defined by derived classes.*/
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virtual Object* clone() const = 0;
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virtual bool isSameKindAs(Object*) { return true; }
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/** return the name of the object's class type. Must be defined
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by derived classes.*/
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virtual const char* className() const = 0;
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/** Template Method/Prototype Pattern : create a clone and read
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Object data from Input. Reads Input and if it matches this
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objects className() then create a clone and match '{' brackets
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and repeating calling Object::readLocalData() until the
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matching ']' is read.*/
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virtual Object* readClone(Input& fr);
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/** Template Method Pattern : write out Object data to Output.
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Sequence of output is className() followed by Open '{'
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and then call Object::writeLocalData() and complete with '}'.*/
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virtual bool write(Output& fw);
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protected:
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/** Object destructor. Note, is protected so that Objects cannot
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be deleted other than by being derefernced and the reference
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count being zero (see osg::Referenced), preventing the deletion
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of nodes which are still in use. This also means that
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Node's cannot be created on stack i.e Node node will not compile,
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forcing all nodes to be created on the heap i.e Node* node
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= new Node().*/
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virtual ~Object() {}
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/** Template Method Pattern : read local data from .osg file.
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Note should be implemented in derivied classes, which
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call their parent class's readLocalData. Returns
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true if the input iterator has been advanced, otherwise false.*/
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virtual bool readLocalData(Input&) { return false; }
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/** Template Method Pattern : write local data to .osg file.
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Note should be implemented in derivied classes, which
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call their parent class's writeLocalData. Returns
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true if data has been written out, otherwise false.*/
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virtual bool writeLocalData(Output&) { return false; }
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private:
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/** disallow any form of deep copy.*/
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Object(Object&): Referenced() {}
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Object& operator = (const Object&) { return *this; }
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};
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};
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#endif
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