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

   1 package org.wamblee.system;
   2
   3 import java.util.ArrayList;
   4 import java.util.Arrays;
   5 import java.util.List;
   6
   7 import org.apache.commons.logging.Log;
   8 import org.apache.commons.logging.LogFactory;
   9
  10 import sun.util.LocaleServiceProviderPool.LocalizedObjectGetter;
  11
  12 /**
  13  * Composite system consisting of multiple subsystems.
  14  *
  15  * @author Erik Brakkee
  16  */
  17 public class Container extends AbstractComponent {
  18
  19         private static final Log LOG = LogFactory.getLog(Container.class);
  20
  21         private Component[] _systems;
  22
  23         /**
  24          * Construcst the composite system.
  25          * @param aName Name of the system.
  26          * @param aRegistry Service registry.
  27          * @param aSystems Subsystems.
  28          * @param aProvided Provided services of the system.
  29          * @param aRequired Required services by the system.
  30          */
  31         public Container(String aName, Component[] aSystems,
  32                         ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
  33                 super(aName, aProvided, aRequired);
  34                 _systems = aSystems;
  35                 validate(aRequired);
  36         }
  37
  38         /**
  39          * Validates the subsystems together to check that there are
  40          * no required services not in the required list and
  41          * no services in the provided list that cannot be provided.
  42          * Also logs a warning in case of superfluous requirements.
  43          */
  44         private void validate(RequiredInterface[] aRequired) {
  45                 List<ProvidedInterface> provided = new ArrayList<ProvidedInterface>();
  46                 for (Component system : _systems) {
  47                         provided.addAll(Arrays.asList(system.getProvidedServices()));
  48                 }
  49
  50                 List<RequiredInterface> required = new ArrayList<RequiredInterface>();
  51                 for (Component system : _systems) {
  52                         required.addAll(Arrays.asList(system.getRequiredServices()));
  53                 }
  54
  55                 for (ProvidedInterface service : getProvidedServices()) {
  56                         if (!(provided.contains(service))) {
  57                                 throw new SystemAssemblyException(getName() + ": Service '" + service
  58                                                 + "' is not provided by any of the subsystems");
  59                         }
  60                 }
  61
  62                 for (RequiredInterface service : getRequiredServices()) {
  63                         if (!(required.contains(service))) {
  64                                 info("Service '"
  65                                                 + service
  66                                                 + "' indicated as required is not actually required by any of the subsystems");
  67                         }
  68                 }
  69
  70                 List<RequiredInterface> reallyRequired = new ArrayList<RequiredInterface>(
  71                                 required);
  72                 // Compute all required interfaces that are not provided
  73                 for (ProvidedInterface service : provided) {
  74                         List<RequiredInterface> fulfilled =
  75                                 Arrays.asList(SystemAssembler.filterRequiredServices(service,
  76                                         reallyRequired));
  77                         reallyRequired.removeAll(fulfilled);
  78                 }
  79                 // Now the remaining interfaces should be covered by the required
  80                 // list.
  81                 reallyRequired.removeAll(Arrays.asList(aRequired));
  82
  83                 String missingRequired = "";
  84                 for (RequiredInterface service: reallyRequired) {
  85                         missingRequired += service + "\n";
  86                 }
  87                 if ( missingRequired.length() > 0 ) {
  88                         throw new SystemAssemblyException(getName() + ": missing required services\n" + missingRequired);
  89                 }
  90         }
  91
  92         @Override
  93         protected void doStart(String aContext) {
  94                 List<ProvidedInterface> provided = new ArrayList<ProvidedInterface>();
  95
  96                 // all interfaces from the required list of this container are
  97                 // provided to the components inside it.
  98                 RequiredInterface[] required = getRequiredServices();
  99                 for (RequiredInterface intf: required) {
 100                     ProvidedInterface provider = intf.getProvider();
 101                     if ( provider == null ) {
 102                         throw new SystemAssemblyException(aContext + ": required interface '" + intf +"' is not provided");
 103                     }
 104                         provided.add(intf.getProvider());
 105                 }
 106
 107                 SystemAssembler assembler = new SystemAssembler( _systems,
 108                                 provided.toArray(new ProvidedInterface[0]));
 109                 assembler.start();
 110         }
 111
 112         @Override
 113         protected void doStop() {
 114                 for (int i = _systems.length-1; i >= 0; i--) {
 115                         _systems[i].stop();
 116                 }
 117         }
 118
 119         private void info(String aMsg) {
 120                 LOG.info(getName() + ": " + aMsg);
 121         }
 122
 123 }