@Override
	protected boolean shouldRemoveFromCache(ProgramLocator locator, Program program) {
		// Only remove the program from the cache if it is not being used by anyone else. The idea
		// is that if it is still being used, it is more likely to be needed again by some other
		// client.
		//
		// Note: when a program is purged due to the cache size limit, this method will not be called 
		return program.getConsumerList().size() <= 1;
	}
Constructs new ProgramCache with a duration for keeping programs open and a maximum
number of programs to cache.
@param duration the time that a program will remain in the cache without being
accessed (accessing a cached program resets its time)
@param capacity the maximum number of programs in the cache before least recently used
programs are removed.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/progmgr/ProgramCache.java