Merge commit '42b2e5ca519766e37ce6941ba4faecc9691cc403' into upstream

[debian/openrocket] / core / src / net / sf / openrocket / plugin / framework / AbstractService.java

diff --git a/core/src/net/sf/openrocket/plugin/framework/AbstractService.java b/core/src/net/sf/openrocket/plugin/framework/AbstractService.java
new file mode 100644 (file)
index 0000000..eca8a2a
--- /dev/null
+++ b/core/src/net/sf/openrocket/plugin/framework/AbstractService.java
@@ -0,0 +1,45 @@
+package net.sf.openrocket.plugin.framework;
+
+import java.util.Collections;
+import java.util.List;
+
+import net.sf.openrocket.util.BugException;
+
+/**
+ * An abstract service implementation that returns plugins of type P.
+ * 
+ * @param <P>  the plugin type that this service returns.
+ * @author Sampo Niskanen <sampo.niskanen@iki.fi>
+ */
+public abstract class AbstractService<P> implements Service {
+       
+       private final Class<P> type;
+       
+       protected AbstractService(Class<P> type) {
+               this.type = type;
+       }
+       
+       @SuppressWarnings("unchecked")
+       @Override
+       public <E> List<E> getPlugins(Class<E> e, Object... args) {
+               
+               if (e != type) {
+                       return Collections.emptyList();
+               }
+               
+               List<P> plugins = getPlugins(args);
+               
+               // Check list content types to avoid mysterious bugs later on
+               for (P p : plugins) {
+                       if (!type.isInstance(p)) {
+                               throw new BugException("Requesting plugins of type " + type + " but received " +
+                                               ((p != null) ? p.getClass() : "null"));
+                       }
+               }
+               
+               return (List<E>) plugins;
+       }
+       
+       protected abstract List<P> getPlugins(Object... args);
+       
+}