How to get active perspective in Eclipse

Active workbench page will have getPerspective() this will return the IPerspectiveDescriptor

IWorkbench workbench = PlatformUI.getWorkbench();
if (workbench != null) {
IWorkbenchWindow activeWorkbenchWindow = workbench.getActiveWorkbenchWindow();
if (activeWorkbenchWindow != null) {
IWorkbenchPage activePage = activeWorkbenchWindow.getActivePage();
if (activePage != null) {
IPerspectiveDescriptor perspective = activePage.getPerspective();
if (perspective != null) {
String id = perspective.getId();
//This is your active perspective
}
}
}