ハンドルの閉じ方¶

The handle is closed when it is reaped by the garbage collector. Because libguestfs handles include a lot of state, it is also possible to close (and hence free) them explicitly by calling the "close" method.

例外¶

Errors from libguestfs functions are mapped into the "LibGuestFSException" exception. This has a single parameter which is the error message (a "String").

Calling any method on a closed handle raises the same exception.

If malloc(3) or some other allocation fails inside the bindings, the "LibGuestFSOutOfMemory" exception is thrown.

イベント¶

The libguestfs event API is fully supported from Java. Create a class which implements the "EventCallback" interface, create an instance of this class, and then call the "GuestFS#set_event_callback" method to register this instance. The "event" method of the class is called when libguestfs generates an event.

For example, this will print all trace events:

 GuestFS g = new GuestFS ();
 g.set_trace (true);
 g.set_event_callback (
   new EventCallback () {
     public void event (long event, int eh,
                        String buffer, long[] array) {
       System.out.println (GuestFS.eventToString (event) +
                           ": " + buffer);
     }
   },
   GuestFS.EVENT_TRACE);
 g.add_drive_ro ("disk.img");
 // etc.

The output looks similar to this:

 EVENT_TRACE: add_drive_ro "disk.img"
 EVENT_TRACE: add_drive_ro = 0
 // etc.

オプション引数¶

Some methods take an optional map of optional parameters. An example of this is "g.add_drive" which can be called in one of two ways:

 g.add_drive ("disk.img");

or with optional arguments:

 Map<String, Object> optargs =
   new HashMap<String, Object>() {
   {
     put ("readonly", Boolean.TRUE);
     put ("format", "raw");
   }
 };
 g.add_drive ("disk.img", optargs);

For more information on this topic, see "CALLS WITH OPTIONAL ARGUMENTS" in guestfs(3).

Optional handle parameters

When creating the handle you can also pass a map of optional parameters:

 Map<String, Object> optargs =
   new HashMap<String, Object>() {
   {
     put ("close_on_exit", Boolean.FALSE);
     put ("environment", Boolean.TRUE);
   }
 };
 GuestFS g = new GuestFS (optargs);

For more information, see "guestfs_create_flags" in guestfs(3).