io Programmo 39/IOPROG_39.ISO/SOFT/sdkjava40.exe/data1.cab/fg_Samples/Samples/COM/IPersist/JCOMSave.cpp

C/C++ Source or Header | 2000-05-04 | 5.6 KB | 170 lines

// ===========================================================================
// File: Client.cpp
//
// This simple COM Client will create an instance of a Java COM object that
// implements the java.io.Serializable interface, and will therefore by
// default have the COM interfaces IPersist, IPersistStreamInit and
// IPersistStorage.  This application will save the state of the COM object
// using these COM interfaces.
//
// The IPersistStreamInit interface will be used to save the state of the COM
// object to an IStream in memory.  The contents of the memory will then be
// printed to standard out as characters.
//
// The IPersistStorage interface will save the contects of the COM object
// into a newly created structured storage file called "jcomsave.doc" that
// can be viewed using the dfview.exe tool that comes with Microsoft Visual
// C++.  Examining the contents of the doc file, you will find one entry which
// has exactly the same bytes as those printed to the screen.
//
// (C) Copyright 1995 - 1999 Microsoft Corporation.  All rights reserved.
// ===========================================================================

// %%Includes: ---------------------------------------------------------------
#include <windows.h>
#include <initguid.h>
#include <stdio.h>
#include <ocidl.h>
#include <objbase.h>
// %%Guids: ------------------------------------------------------------------
DEFINE_GUID(CLSID_JavaObject, 0xFE59F510, 0x2D5D, 0x11d2, 0xB9, 0x0F, 0x00, 0xC0, 0x4F, 0x8C, 0x94, 0x91);

// ---------------------------------------------------------------------------
// %%Function: main
//
// This creates the COM object, and saves it to an IStream and IStorage.
// ---------------------------------------------------------------------------
int main( int argc, char **argv )
 {
     HRESULT hr =0; //Holds the result of each function call.

     IPersistStreamInit* pPersist = NULL;
     IStream* ppstm = NULL;

     // initialize COM
    hr = CoInitialize(NULL);

    if (SUCCEEDED(hr))
    {
    // create an instance of our Java implemented COM object.
        IUnknown* punk = NULL;

        hr = CoCreateInstance(CLSID_JavaObject,
                        NULL,
                        CLSCTX_INPROC_SERVER,
                        IID_IUnknown,
                        (void**)&punk);
        if (SUCCEEDED(hr))
        {
    // Get the IPersistStreamInit interface from our COM object.
           hr = punk->QueryInterface(IID_IPersistStreamInit,
                            (void**)&pPersist);

           punk->Release();
        }
    }
    if (SUCCEEDED(hr))
    {

    // Create an in memory Stream that will be used to store the COM object.

        hr = CreateStreamOnHGlobal(NULL,
                                false,
                                &ppstm);
        if (SUCCEEDED(hr))
        {

    // Saves the contents of the COM object to the IStream in memory.

            hr = pPersist->Save(ppstm,
                    TRUE);
        }
    }
    if (SUCCEEDED(hr))
    {
    // Get the number of bytes that were written to the IStream.
    //
    // NOTE: do not use IPersistStreamInit::GetSizeMax(ULARGE_INTEGER) as this will
    //              always return E_NOTIMPL.

        STATSTG stat;
        hr = ppstm->Stat(&stat,1);
        if (SUCCEEDED(hr))
        {
            ULARGE_INTEGER streamSize = stat.cbSize;

    // To lock the IStream data when we are reading its contents we will need an HGlobal.

            HGLOBAL hGlobal;
            hr= GetHGlobalFromStream(ppstm,&hGlobal);
            if (SUCCEEDED(hr))
            {

    // Lock the IStream data , and get a pointer to the first byte.

                byte* pState = (byte*)GlobalLock(hGlobal);

                if (pState==NULL)
                {
                    hr = E_FAIL;
                }
                if (SUCCEEDED(hr))
                {
    //Write the bytes stored in the IStream to standard out..

                    for (DWORD i=0;i<streamSize.LowPart;i++)
                    {
                        printf("%c ",*pState);
                        pState++;
                    }
    // Unlock the IStream

                    GlobalUnlock(hGlobal);

                    ppstm->Release();
                    ppstm=NULL;
                }
            }
        }
    }
//
// This section illustrates the use of the IPersistStorage interface.
//
    if (SUCCEEDED(hr))
    {
    // Get the IPersistStreamInit interface from our COM object.

        IPersistStorage* pPersistStorage = NULL;

        hr = pPersist->QueryInterface(IID_IPersistStorage,
                            (void**)&pPersistStorage);
        pPersist->Release();
        pPersist=NULL;
        if (SUCCEEDED(hr))
        {
    // Create a new file that will be our IStorage object.

            IStorage* pIStorage = NULL;
            WCHAR* foo =L"jcomsave.doc";

            hr = StgCreateDocfile(foo,
                            STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE,
                            0,
                            &pIStorage);
            if (SUCCEEDED(hr))
            {
    //Store the COM object in the IStorage file.

                hr = pPersistStorage->Save(pIStorage,FALSE);
                pIStorage->Release();
            }

            pPersistStorage->Release();
        }
    }

    // Free the memory associated with the IStream
    if (pPersist!=NULL) pPersist->Release();
    if (ppstm!=NULL) ppstm->Release();
 return hr;
}  // main