plugins/net.mograsim.machine/src/net/mograsim/machine/MachineRegistry.java

   1 package net.mograsim.machine;
   2
   3 import java.util.Collections;
   4 import java.util.HashMap;
   5 import java.util.HashSet;
   6 import java.util.Map;
   7 import java.util.Objects;
   8 import java.util.Set;
   9
  10 import org.eclipse.core.runtime.CoreException;
  11 import org.eclipse.core.runtime.IConfigurationElement;
  12 import org.eclipse.core.runtime.IExtension;
  13 import org.eclipse.core.runtime.IExtensionPoint;
  14 import org.eclipse.core.runtime.IExtensionRegistry;
  15 import org.eclipse.core.runtime.IRegistryEventListener;
  16 import org.eclipse.core.runtime.Platform;
  17
  18 /**
  19  * The MachineRegsitry is a static context registry for all {@link MachineDefinition}s known at any point during runtime.
  20  * <p>
  21  * It is updated automatically as mograsim machine definition extension points ({@link #MACHINE_EXT_ID}) are added or removed.
  22  *
  23  * @author Christian Femers
  24  *
  25  */
  26 public class MachineRegistry
  27 {
  28
  29         public static final String MACHINE_EXT_ID = "net.mograsim.machine.machine_definition";
  30
  31         private static final Map<String, MachineDefinition> installedMachines = Collections.synchronizedMap(new HashMap<>());
  32         private static final Set<MachineRegistryListener> listeners = Collections.synchronizedSet(new HashSet<>());
  33
  34         private static void reload()
  35         {
  36                 installedMachines.clear();
  37                 IExtensionRegistry registry = Platform.getExtensionRegistry();
  38                 IConfigurationElement[] config = registry.getConfigurationElementsFor(MACHINE_EXT_ID);
  39                 try
  40                 {
  41                         for (IConfigurationElement e : config)
  42                         {
  43                                 final Object o = e.createExecutableExtension("class");
  44                                 final String id = e.getAttribute("unique_id");
  45                                 if (o instanceof MachineDefinition)
  46                                 {
  47                                         MachineDefinition md = (MachineDefinition) o;
  48                                         if (Objects.equals(id, md.getId()))
  49                                                 installedMachines.put(id, md);
  50                                         else
  51                                                 System.err.println("Machine definition ids to not match: " + id + " and " + md.getId());
  52                                 } else
  53                                 {
  54                                         System.err.println("Invalid machine definition: " + o + "(id=" + id + "");
  55                                 }
  56                         }
  57                 }
  58                 catch (CoreException ex)
  59                 {
  60                         System.err.println("An error occurred reloading the machines:");
  61                         ex.printStackTrace();
  62                 }
  63                 notifyListeners();
  64         }
  65
  66         public static void initialize()
  67         {
  68                 reload();
  69                 Platform.getExtensionRegistry().addListener(new IRegistryEventListener()
  70                 {
  71
  72                         @Override
  73                         public void removed(IExtensionPoint[] extensionPoints)
  74                         {
  75                                 // nothing?
  76                         }
  77
  78                         @Override
  79                         public void removed(IExtension[] extensions)
  80                         {
  81                                 reload();
  82                         }
  83
  84                         @Override
  85                         public void added(IExtensionPoint[] extensionPoints)
  86                         {
  87                                 // nothing?
  88                         }
  89
  90                         @Override
  91                         public void added(IExtension[] extensions)
  92                         {
  93                                 reload();
  94                         }
  95                 }, MACHINE_EXT_ID);
  96         }
  97
  98         public static Map<String, MachineDefinition> getInstalledMachines()
  99         {
 100                 return Collections.unmodifiableMap(installedMachines);
 101         }
 102
 103         public static MachineDefinition getMachine(String id)
 104         {
 105                 return installedMachines.get(id);
 106         }
 107
 108         private static void notifyListeners()
 109         {
 110                 Map<String, MachineDefinition> unmodMachines = getInstalledMachines();
 111                 listeners.forEach(l -> l.onReload(unmodMachines));
 112         }
 113
 114         public static void addMachineRegistryListener(MachineRegistryListener listener)
 115         {
 116                 listeners.add(listener);
 117         }
 118
 119         public static void removeMachineRegistryListener(MachineRegistryListener listener)
 120         {
 121                 listeners.remove(listener);
 122         }
 123
 124         @FunctionalInterface
 125         public interface MachineRegistryListener
 126         {
 127                 void onReload(Map<String, MachineDefinition> installedMachines);
 128         }
 129 }