Class Resource

  extended by edu.wpi.first.wpilibj.Resource

public class Resource
extends java.lang.Object

Track resources in the program. The Resource class is a convenient way of keeping track of allocated arbitrary resources in the program. Resources are just indicies that have an lower and upper bound that are tracked by this class. In the library they are used for tracking allocation of hardware channels but this is purely arbitrary. The resource class does not do any actual allocation, but simply tracks if a given index is currently in use. WARNING: this should only be statically allocated. When the program loads into memory all the static constructors are called. At that time a linked list of all the "Resources" is created. Then when the program actually starts - in the Robot constructor, all resources are initialized. This ensures that the program is restartable in memory without having to unload/reload.

Constructor Summary
Resource(int size)
          Allocate storage for a new instance of Resource.
Method Summary
 int allocate()
          Allocate a resource.
 int allocate(int index)
          Allocate a specific resource value.
 void free(int index)
          Free an allocated resource.
static void restartProgram()
          Clears all allocated resources
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail


public Resource(int size)
Allocate storage for a new instance of Resource. Allocate a bool array of values that will get initialized to indicate that no resources have been allocated yet. The indicies of the resources are 0..size-1.

size - The number of blocks to allocate
Method Detail


public static void restartProgram()
Clears all allocated resources


public int allocate()
             throws CheckedAllocationException
Allocate a resource. When a resource is requested, mark it allocated. In this case, a free resource value within the range is located and returned after it is marked allocated.

The index of the allocated block.
CheckedAllocationException - If there are no resources available to be allocated.


public int allocate(int index)
             throws CheckedAllocationException
Allocate a specific resource value. The user requests a specific resource value, i.e. channel number and it is verified unallocated, then returned.

index - The resource to allocate
The index of the allocated block
CheckedAllocationException - If there are no resources available to be allocated.


public void free(int index)
Free an allocated resource. After a resource is no longer needed, for example a destructor is called for a channel assignment class, Free will release the resource value so it can be reused somewhere else in the program.

index - The index of the resource to free.