jna CoCreateInstance - jna

Question

am trying to create a link in windows 7 that has an icon. I am using the JNA library for this. I am having trouble with the call to CoCreateInstance. It returns error. First I am not sure if the GUID for IShellLink is the correct ( I am not a windows programer). Below is my code so far. Once I get the pointer to an IShellLink I would need to fill the paramaters for the link (target,icon, description, etc). I am modeling this call from the C code below found at this link (http://www.codeproject.com/Articles/11467/How-to-create-short-cuts-link-files). I know I could use mklink command for this but it does have an option to add an icon and description.
private void createLink(){
Pointer reserved = null; //Must be null
int dwCoInit = 0;
HRESULT oleInitResult = Ole32.INSTANCE.CoInitializeEx(reserved,dwCoInit);
if(oleInitResult.equals(W32Errors.S_OK)){
GUID rclsid = Ole32Util.getGUIDFromString("{e82a2d71-5b2f-43a0-97b8-81be15854de8}"); //Shell object
GUID riid = Ole32Util.getGUIDFromString("{000214EE-0000-0000-C000-000000000046}"); //CLSID of the IShellLink object
PointerByReference ppv = new PointerByReference();
HRESULT oleCreateResult = Ole32.INSTANCE.CoCreateInstance(rclsid,null,ObjBase.CLSCTX_INPROC,riid,ppv);
if(oleCreateResult.equals(W32Errors.S_OK)){
}else{
System.out.println("Failed to create link error "+oleCreateResult.intValue());
}
}
Ole32.INSTANCE.CoUninitialize();
}
###################### C++ Sample code
/*
--------------------------------------------------------------------------------
Description: Creates the actual 'lnk' file (assumes COM has been initialized).
Parameters: pszTargetfile - File name of the link's target, must be a non-empty string.
pszTargetargs - Command line arguments passed to link's target, may be an empty string.
pszLinkfile - File name of the actual link file, must be a non-empty string.
pszDescription - Description of the linked item. If this is an empty string the description is not set.
iShowmode - ShowWindow() constant for the link's target. Use one of:
1 (SW_SHOWNORMAL) = Normal window.
3 (SW_SHOWMAXIMIZED) = Maximized.
7 (SW_SHOWMINNOACTIVE) = Minimized.
If this is zero the showmode is not set.
pszCurdir - Working directory of the active link. If this is an empty string the directory is not set.
pszIconfile - File name of the icon file used for the link. If this is an empty string the icon is not set.
iIconindex - Index of the icon in the icon file. If this is < 0 the icon is not set.
Returns: HRESULT value >= 0 for success, < 0 for failure.
--------------------------------------------------------------------------------
*/
static HRESULT CreateShortCut(LPSTR pszTargetfile, LPSTR pszTargetargs, LPSTR pszLinkfile, LPSTR pszDescription,
int iShowmode, LPSTR pszCurdir, LPSTR pszIconfile, int iIconindex) {
HRESULT hRes; /* Returned COM result code */
IShellLink* pShellLink; /* IShellLink object pointer */
IPersistFile* pPersistFile; /* IPersistFile object pointer */
WORD wszLinkfile[MAX_PATH]; /* pszLinkfile as Unicode string */
int iWideCharsWritten; /* Number of wide characters written */
hRes = E_INVALIDARG;
if (
(pszTargetfile != NULL) && (strlen(pszTargetfile) > 0) &&
(pszTargetargs != NULL) &&
(pszLinkfile != NULL) && (strlen(pszLinkfile) > 0) &&
(pszDescription != NULL) &&
(iShowmode >= 0) &&
(pszCurdir != NULL) &&
(pszIconfile != NULL) &&
(iIconindex >= 0)
) {
hRes = CoCreateInstance(&CLSID_ShellLink, /* pre-defined CLSID of the IShellLink object */
NULL, /* pointer to parent interface if part of aggregate */
CLSCTX_INPROC_SERVER, /* caller and called code are in same process */
&IID_IShellLink, /* pre-defined interface of the IShellLink object */
&pShellLink); /* Returns a pointer to the IShellLink object */
if (SUCCEEDED(hRes))
{
/* Set the fields in the IShellLink object */
hRes = pShellLink->lpVtbl->SetPath(pShellLink, pszTargetfile);
hRes = pShellLink->lpVtbl->SetArguments(pShellLink, pszTargetargs);
if (strlen(pszDescription) > 0)
{
hRes = pShellLink->lpVtbl->SetDescription(pShellLink, pszDescription);
}
if (iShowmode > 0)
{
hRes = pShellLink->lpVtbl->SetShowCmd(pShellLink, iShowmode);
}
if (strlen(pszCurdir) > 0)
{
hRes = pShellLink->lpVtbl->SetWorkingDirectory(pShellLink, pszCurdir);
}
if (strlen(pszIconfile) > 0 && iIconindex >= 0)
{
hRes = pShellLink->lpVtbl->SetIconLocation(pShellLink, pszIconfile, iIconindex);
}
/* Use the IPersistFile object to save the shell link */
hRes = pShellLink->lpVtbl->QueryInterface(pShellLink, /* existing IShellLink object */
&IID_IPersistFile, /* pre-defined interface of the IPersistFile object */
&pPersistFile); /* returns a pointer to the IPersistFile object */
if (SUCCEEDED(hRes))
{
iWideCharsWritten = MultiByteToWideChar(CP_ACP, 0, pszLinkfile, -1, wszLinkfile, MAX_PATH);
hRes = pPersistFile->lpVtbl->Save(pPersistFile, wszLinkfile, TRUE);
pPersistFile->lpVtbl->Release(pPersistFile);
}
pShellLink->lpVtbl->Release(pShellLink);
}
}
return (hRes);
}

Answer 1

It turn out to be very simple. So If you hit this page you probably will save couple days by following this instructions:
Generate the mappings for the shell32.dll per instructions in the com4j site:
http://com4j.java.net/tutorial.html
Then just call the following to create the icons. It is very simple once you know.
IWshShell3 shellLink = ClassFactory.createWshShell();
Com4jObject obj = shellLink.createShortcut(linkPath.getAbsolutePath());
IWshShortcut link = obj.queryInterface(IWshShortcut.class);
link.workingDirectory(desktopPath.getAbsolutePath());
link.description("My Link");
link.arguments(" Hello ");
link.iconLocation(iconPath.getAbsolutePath());
link.targetPath(javawsPath.getAbsolutePath());
link.setName("Test Link");
link.save();

Answer 2

I have fixed the called to CoCreateInstance by changing the GUID. Below is the code and it returns OK. But now that I got the pointer I am not sure how to set the parameters I need (link name, target name, desc, icon). Anybody has any suggestions?
GUID rclsid = Ole32Util.getGUIDFromString("{00021401-0000-0000-C000-000000000046}"); //CLSID_ShellLink
if (W32Errors.FAILED(hr.intValue())) {
Ole32.INSTANCE.CoUninitialize();
throw new Exception("Shell Object GUID failed.");
}
GUID riid = Ole32Util.getGUIDFromString("{000214EE-0000-0000-C000-000000000046}"); //CLSID of the IShellLink object
PointerByReference ppv = new PointerByReference();
hr = Ole32.INSTANCE.CoCreateInstance(rclsid,null,WTypes.CLSCTX_LOCAL_SERVER,riid,ppv);
if(hr.equals(W32Errors.S_OK)){
Pointer type = ppv.getValue();
}else{
System.out.println("Failed to create link error "+hr.intValue());
}