1 files changed, 28 insertions, 7 deletions

diff --git a/compatibility/Context.java b/compatibility/Context.java
index 1ec0f54..afd0b15 100644
--- a/compatibility/Context.java
+++ b/compatibility/Context.java
@@ -1,22 +1,43 @@
 package cbt;
 import java.io.*;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.*;
+import java.util.concurrent.*;
 
 // TODO: try to reduce the number of members
-public abstract class Context{
+public interface Context{
+  // recently added methods that needs default values for old versions to work
+  public default long cbtLastModified(){
+    throw new IncompatibleCbtVersionException("You need to define method cbtLastModified.");
+  };
+  public default Map<Object,Object> persistentCache(){
+    throw new IncompatibleCbtVersionException("You need to define method persistentCache.");
+  };
+  public default Map<Object,Object> transientCache(){
+    throw new IncompatibleCbtVersionException("You need to define method transientCache.");
+  };
+  public default long start(){
+    throw new IncompatibleCbtVersionException("You need to define method start.");
+  };
+
+  // methods that exist for longer which every CBT version in use should have by now, no default values needed
   public abstract File projectDirectory();
   public abstract File cwd(); // REPLACE by something that allows to run cbt on some other directly
   public abstract String[] argsArray(); // replace this by https://github.com/cvogt/cbt/issues/172 ?
   public abstract String[] enabledLoggersArray();
-  public abstract Long startCompat();
-  public abstract Boolean cbtHasChangedCompat();
   public abstract String scalaVersionOrNull(); // needed to propagate scalaVersion to dependendee builds
-  public abstract ConcurrentHashMap<String,Object> permanentKeys();
-  public abstract ConcurrentHashMap<Object,ClassLoader> permanentClassLoaders();
-  public abstract ConcurrentHashMap<Object,Object> taskCache();
   public abstract File cache();
   public abstract File cbtHome();
   public abstract File cbtRootHome(); // REMOVE
   public abstract File compatibilityTarget(); // maybe replace this with search in the classloader for it?
   public abstract BuildInterface parentBuildOrNull();
+
+  // deprecated methods
+  @java.lang.Deprecated
+  public abstract Long startCompat();
+  @java.lang.Deprecated
+  public abstract Boolean cbtHasChangedCompat();
+  @java.lang.Deprecated
+  public abstract ConcurrentHashMap<String,Object> permanentKeys();
+  @java.lang.Deprecated
+  public abstract ConcurrentHashMap<Object,ClassLoader> permanentClassLoaders();
 }