wamblee.org Git - utils/blob - system/general/src/main/java/org/wamblee/system/AbstractSubSystem.java

   1 package org.wamblee.system;
   2
   3 import java.util.ArrayList;
   4 import java.util.Arrays;
   5 import java.util.HashMap;
   6 import java.util.List;
   7 import java.util.Map;
   8
   9 import org.apache.commons.logging.Log;
  10 import org.apache.commons.logging.LogFactory;
  11
  12 /**
  13  * Abstract subsystem class making it easy to implement new
  14  * subsystems.
  15  */
  16 public abstract class AbstractSubSystem implements SubSystem {
  17
  18         private static final Log LOG = LogFactory.getLog(AbstractSubSystem.class);
  19
  20         private String _name;
  21         private List<ServiceDescriptor> _provided;
  22         private List<ServiceDescriptor> _required;
  23         private Map<ServiceDescriptor, Service> _running;
  24
  25         /**
  26          * Constructs the subsystem.
  27          * @param aName Name of the system.
  28          * @param aProvided Provided services.
  29          * @param aRequired Required services.
  30          */
  31         protected AbstractSubSystem(String aName, ServiceDescriptor[] aProvided,
  32                         ServiceDescriptor[] aRequired) {
  33                 _name = aName;
  34                 _provided = new ArrayList<ServiceDescriptor>();
  35                 _provided.addAll(Arrays.asList(aProvided));
  36                 _required = new ArrayList<ServiceDescriptor>();
  37                 _required.addAll(Arrays.asList(aRequired));
  38                 _running = new HashMap<ServiceDescriptor, Service>();
  39         }
  40
  41         @Override
  42         public final String getName() {
  43                 return _name;
  44         }
  45
  46         @Override
  47         public final ServiceDescriptor[] getProvidedServices() {
  48                 return _provided.toArray(new ServiceDescriptor[0]);
  49         }
  50
  51         @Override
  52         public final ServiceDescriptor[] getRequiredServices() {
  53                 return _required.toArray(new ServiceDescriptor[0]);
  54         }
  55
  56         @Override
  57         public final Service[] initialize(String aContext, Service[] aRequiredServices) {
  58                 LOG.info("Initializing '" + aContext + "." + _name + "' with " + Arrays.asList(aRequiredServices));
  59                 doInitialize(aContext + "." + getName(), aRequiredServices);
  60                 return _running.values().toArray(new Service[0]);
  61         }
  62
  63         /**
  64          * Must be implemented for initializing the subsystem.
  65          * The implementation must call {@link #addService(Service)}
  66          * for each service that is started.
  67          * @param aRequiredServices Services that are already running
  68          * from other subsystems that may be used.
  69          */
  70         protected abstract void doInitialize(String aContext, Service[] aRequiredServices);
  71
  72         /**
  73          * Implementations must call this method to indicate that
  74          * a new service has been started.
  75          * @param aService Service.
  76          */
  77         protected final void addService(String aContext, Service aService) {
  78                 LOG.info(aContext + ": service '" + aService + "' started.");
  79                 _running.put(aService.getDescriptor(), aService);
  80         }
  81
  82         @Override
  83         public Service[] getRunningServices() {
  84                 return _running.values().toArray(new Service[0]);
  85         }
  86
  87         @Override
  88         public String toString() {
  89                 return _name;
  90         }
  91
  92 }