src/java.base/share/classes/java/lang/invoke/MethodType.java

rev 13059 : 8130227: Extend MethodHandle APIs

@@ -470,13 +470,13 @@
     /** Replace the last arrayLength parameter types with the component type of arrayType.
      * @param arrayType any array type
      * @param arrayLength the number of parameter types to change
      * @return the resulting type
      */
-    /*non-public*/ MethodType asSpreaderType(Class<?> arrayType, int arrayLength) {
+    /*non-public*/ MethodType asSpreaderType(Class<?> arrayType, int pos, int arrayLength) {
         assert(parameterCount() >= arrayLength);
-        int spreadPos = ptypes.length - arrayLength;
+        int spreadPos = pos;
         if (arrayLength == 0)  return this;  // nothing to change
         if (arrayType == Object[].class) {
             if (isGeneric())  return this;  // nothing to change
             if (spreadPos == 0) {
                 // no leading arguments to preserve; go generic

@@ -487,14 +487,14 @@
                 return res;
             }
         }
         Class<?> elemType = arrayType.getComponentType();
         assert(elemType != null);
-        for (int i = spreadPos; i < ptypes.length; i++) {
+        for (int i = spreadPos; i < spreadPos + arrayLength; i++) {
             if (ptypes[i] != elemType) {
                 Class<?>[] fixedPtypes = ptypes.clone();
-                Arrays.fill(fixedPtypes, i, ptypes.length, elemType);
+                Arrays.fill(fixedPtypes, i, spreadPos + arrayLength, elemType);
                 return methodType(rtype, fixedPtypes);
             }
         }
         return this;  // arguments check out; no change
     }

@@ -510,16 +510,18 @@
         return ptype;
     }
 
     /** Delete the last parameter type and replace it with arrayLength copies of the component type of arrayType.
      * @param arrayType any array type
+     * @param pos position at which to insert parameters
      * @param arrayLength the number of parameter types to insert
      * @return the resulting type
      */
-    /*non-public*/ MethodType asCollectorType(Class<?> arrayType, int arrayLength) {
+    /*non-public*/ MethodType asCollectorType(Class<?> arrayType, int pos, int arrayLength) {
         assert(parameterCount() >= 1);
-        assert(lastParameterType().isAssignableFrom(arrayType));
+        assert(pos < ptypes.length);
+        assert(ptypes[pos].isAssignableFrom(arrayType));
         MethodType res;
         if (arrayType == Object[].class) {
             res = genericMethodType(arrayLength);
             if (rtype != Object.class) {
                 res = res.changeReturnType(rtype);

@@ -530,11 +532,15 @@
             res = methodType(rtype, Collections.nCopies(arrayLength, elemType));
         }
         if (ptypes.length == 1) {
             return res;
         } else {
-            return res.insertParameterTypes(0, parameterList().subList(0, ptypes.length-1));
+            // insert after (if need be), then before
+            if (pos < parameterList().size() - 1) {
+                res = res.insertParameterTypes(arrayLength, parameterList().subList(pos + 1, parameterList().size()));
+            }
+            return res.insertParameterTypes(0, parameterList().subList(0, pos));
         }
     }
 
     /**
      * Finds or creates a method type with some parameter types omitted.