Damage step frames

Author: Yeregorix

src/main/java/org/spongepowered/api/event/cause/entity/damage/DamageModifier.java

@@ -25,12 +25,13 @@
 package org.spongepowered.api.event.cause.entity.damage;
 
 import org.spongepowered.api.Sponge;
-import org.spongepowered.api.event.Cause;
+import org.spongepowered.api.event.CauseStackManager;
 
 import java.util.Optional;
+import java.util.function.Consumer;
 
 /**
- * A damage modifier that is or may become a {@link DamageStep}.
+ * A damage modifier that will create a {@link DamageStep}.
  */
 public interface DamageModifier {
 
@@ -42,20 +43,19 @@ public interface DamageModifier {
     DamageStepType type();
 
     /**
-     * Gets the {@link Cause} of this modifier.
+     * Gets the consumer that will modify the cause frame.
      *
-     * @return The cause
+     * @return The cause frame modifier
      */
-    Cause cause();
+    Optional<Consumer<CauseStackManager.StackFrame>> frame();
 
     /**
-     * Gets the function that modify the damage.
-     * The function may be absent if the sole purpose of this modifier is to apply children steps,
-     * or if the step was made by the platform, usually the root step.
+     * Gets the function that will modify the damage.
+     * The function may be absent if the sole purpose of this modifier is to apply children steps.
      *
-     * @return the modifier function
+     * @return the damage modifier
      */
-    Optional<Function> function();
+    Optional<Function> damage();
 
     @FunctionalInterface
     interface Function {
@@ -78,18 +78,6 @@ static Builder builder() {
         return Sponge.game().builderProvider().provide(Builder.class);
     }
 
-    /**
-     * Creates a new {@link DamageModifier}.
-     *
-     * @param type The damage step type
-     * @param cause The modifier cause
-     * @param function The modifier function
-     * @return The new damage modifier
-     */
-    static DamageModifier of(DamageStepType type, Cause cause, Function function) {
-        return DamageModifier.builder().type(type).cause(cause).function(function).build();
-    }
-
     /**
      * A builder to create {@link DamageModifier}s.
      */
@@ -104,19 +92,19 @@ interface Builder extends org.spongepowered.api.util.Builder<DamageModifier, Bui
         Builder type(DamageStepType type);
 
         /**
-         * Sets the {@link Cause} for this modifier.
+         * Sets the cause frame modifier.
          *
-         * @param cause The modifier cause
+         * @param frameModifier The frame modifier
          * @return this builder for chaining
          */
-        Builder cause(Cause cause);
+        Builder frame(Consumer<CauseStackManager.StackFrame> frameModifier);
 
         /**
          * Sets the {@link Function} for this modifier.
          *
-         * @param function The modifier function
+         * @param function The damage function
          * @return this builder for chaining
          */
-        Builder function(Function function);
+        Builder damage(Function function);
     }
 }

src/main/java/org/spongepowered/api/event/cause/entity/damage/DamageStep.java

@@ -24,6 +24,8 @@
  */
 package org.spongepowered.api.event.cause.entity.damage;
 
+import org.spongepowered.api.event.Cause;
+
 import java.util.List;
 import java.util.Optional;
 import java.util.OptionalDouble;
@@ -33,7 +35,21 @@
  * Steps are structured as trees where children modify the input or output of the parent step.
  * A damage calculation is made of multiple trees of steps.
  */
-public interface DamageStep extends DamageModifier {
+public interface DamageStep {
+
+    /**
+     * Gets the {@link DamageStepType} of this step.
+     *
+     * @return the step type
+     */
+    DamageStepType type();
+
+    /**
+     * Gets the {@link Cause} of this step.
+     *
+     * @return The cause of this step
+     */
+    Cause cause();
 
     /**
      * Gets whether this step is skipped.