LibreOffice: XJavaVM Interface Reference

LibreOffice LibreOffice 7.5 SDK API Reference

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Public Member Functions | List of all members
XJavaVM Interface Referencepublished

must be implemented by the user of the XJavaVM. More...

Inheritance diagram for XJavaVM:

## Public Member Functions
any | getJavaVM ([in] sequence< byte > processID)
| returns the address of the Java Virtual Machine.
boolean | isVMStarted ()
| returns `TRUE` if the VM is started successfully, otherwise `FALSE`.
boolean | isVMEnabled ()
| Returns `TRUE` if the VM is enabled.
Public Member Functions inherited from XInterface
any | queryInterface ([in] type aType)
| queries for a new interface to an existing UNO object.
void | acquire ()
| increases the reference counter by one.
void | release ()
| decreases the reference counter by one.

## Detailed Description

must be implemented by the user of the XJavaVM.

Deprecated:
  A UNO interface seems to be at the wrong abstraction level for this functionality (also, the C++ classes `jvmaccess::VirtualMachine` and `jvmaccess::UnoVirtualMachine` used by com::sun::star::java::XJavaVM::getJavaVM() are not part of the public C++ UNO runtime API). This should probably be replaced by an appropriate C/C++ API.

## Member Function Documentation

## ◆ getJavaVM()

any getJavaVM | ( | [in] sequence< byte > | processID | ) |

returns the address of the Java Virtual Machine.

If the VM is not already instantiated, it will be now.

If the `processID` is a normal 16-byte ID, the returned `any` contains a JNI `JavaVM` pointer as a `long` or `hyper` integer (depending on the platform). If the `processID` does not match the current process, or if the VM cannot be instantiated for whatever reason, a `VOID` `any` is returned.

If the `processID` has an additional 17th byte of value `0`, the returned `any` contains a non–reference-counted pointer to a (reference-counted) instance of the C++ `jvmaccess::VirtualMachine` class, always represented as a `hyper` integer. The pointer is guaranteed to be valid as long as the reference to this com::sun::star::java::XJavaVM is valid (but the pointer should be converted into a reference-counted reference as soon as possible). Again, if the first 16 bytes of the `processID` do not match the current process, or if the VM cannot be instantiated for whatever reason, a `VOID` `any` is returned.

If the `processID` has an additional 17th byte of value `1`, the returned `any` contains a non–reference-counted pointer to a (reference-counted) instance of the C++ `jvmaccess::UnoVirtualMachine` class, always represented as a `hyper` integer. The pointer is guaranteed to be valid as long as the reference to this com::sun::star::java::XJavaVM is valid. Again, if the first 16 bytes of the `processID` do not match the current process, or if the VM cannot be instantiated for whatever reason, a `VOID` `any` is returned.

The first form (returning a JNI `JavaVM` pointer) is mainly for backwards compatibility, new code should use the second form (returning a pointer to a `jvmaccess::VirtualMachine`) if it does not want to use the Java UNO environment, and it should use the third form (returning a pointer to a `jvmaccess::UnoVirtualMachine`) if it wants to use the Java UNO environment. For example, one advantage of using `jvmaccess::VirtualMachine` instead of the raw `JavaVM` pointer is that whenever you attach a native thread to the Java virtual machine, that thread's context `ClassLoader` (see `java.lang.Thread.getContextClassLoader`) will automatically be set to a meaningful value.

Parameters

  processID | The process ID of the caller's process, possibly extended by a 17th byte of value `0` or `1`.

Returns
  On success, the `any` contains a pointer represented as `long` or `hyper`, otherwise the `any` is `VOID`.

## ◆ isVMEnabled()

boolean isVMEnabled | ( |  | ) |

Returns `TRUE` if the VM is enabled.

It is only possible to get the VM, if this method return 0.

## ◆ isVMStarted()

boolean isVMStarted | ( |  | ) |

returns `TRUE` if the VM is started successfully, otherwise `FALSE`.

The documentation for this interface was generated from the following file:

- com/sun/star/java/XJavaVM.idl