Add a 'fallback' to InheritanceMap

setFallback() allows an IInheritanceProvider to be specified which
will be consulted when inheritance for a requested class is unavailable.
If it returns a value, the inheritance will be cached in the InheritanceMap.

src/main/java/net/md_5/specialsource/InheritanceMap.java

@@ -40,6 +40,7 @@ import java.util.*;
 public class InheritanceMap implements IInheritanceProvider {
 
     private final Map<String, ArrayList<String>> inheritanceMap = new HashMap<String, ArrayList<String>>();
+    private IInheritanceProvider fallback = null;
 
     public static final InheritanceMap EMPTY = new InheritanceMap();
 
@@ -70,6 +71,9 @@ public class InheritanceMap implements IInheritanceProvider {
         }
     }
 
+    /**
+     * Save inheritance map to disk
+     */
     public void save(PrintWriter writer) {
         List<String> classes = new ArrayList<String>(inheritanceMap.keySet());
         Collections.sort(classes);
@@ -83,6 +87,9 @@ public class InheritanceMap implements IInheritanceProvider {
         }
     }
 
+    /**
+     * Load from disk, optionally remapped and unremapped through a class map
+     */
     public void load(BufferedReader reader, BiMap<String, String> classMap) throws IOException {
         String line;
 
@@ -119,10 +126,26 @@ public class InheritanceMap implements IInheritanceProvider {
         }
     }
 
+    /**
+     * Get the superclass and interfaces implemented by a class
+     */
     public List<String> getParents(String className) {
-        return inheritanceMap.get(className);
+        List<String> parents = inheritanceMap.get(className);
+
+        if (parents == null && fallback != null) {
+            parents = fallback.getParents(className);
+            if (parents != null) {
+                // cache
+                setParents(className, (ArrayList<String>) parents);
+            }
         }
 
+        return parents;
+    }
+
+    /**
+     * Set the superclass and interfaces implemented by a class
+     */
     public void setParents(String className, ArrayList<String> parents) {
         inheritanceMap.put(className, parents);
     }
@@ -130,4 +153,12 @@ public class InheritanceMap implements IInheritanceProvider {
     public int size() {
         return inheritanceMap.size();
     }
+
+    /**
+     * Set an optional fallback inheritance provider to be consulted when the class is not available
+     * in the inheritance map. Results from the fallback will be cached.
+     */
+    public void setFallback(IInheritanceProvider fallback) {
+        this.fallback = fallback;
+    }
 }