| /* |
| * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.lang.invoke; |
| |
| import java.util.Arrays; |
| import static java.lang.invoke.LambdaForm.*; |
| import static java.lang.invoke.MethodHandleStatics.*; |
| |
| /** |
| * A method handle whose invocation behavior is determined by a target. |
| * The delegating MH itself can hold extra "intentions" beyond the simple behavior. |
| * @author jrose |
| */ |
| /*non-public*/ |
| abstract class DelegatingMethodHandle extends MethodHandle { |
| protected DelegatingMethodHandle(MethodHandle target) { |
| this(target.type(), target); |
| } |
| |
| protected DelegatingMethodHandle(MethodType type, MethodHandle target) { |
| super(type, chooseDelegatingForm(target)); |
| } |
| |
| protected DelegatingMethodHandle(MethodType type, LambdaForm form) { |
| super(type, form); |
| } |
| |
| /** Define this to extract the delegated target which supplies the invocation behavior. */ |
| protected abstract MethodHandle getTarget(); |
| |
| @Override |
| abstract MethodHandle asTypeUncached(MethodType newType); |
| |
| @Override |
| MemberName internalMemberName() { |
| return getTarget().internalMemberName(); |
| } |
| |
| @Override |
| boolean isInvokeSpecial() { |
| return getTarget().isInvokeSpecial(); |
| } |
| |
| @Override |
| Class<?> internalCallerClass() { |
| return getTarget().internalCallerClass(); |
| } |
| |
| @Override |
| MethodHandle copyWith(MethodType mt, LambdaForm lf) { |
| // FIXME: rethink 'copyWith' protocol; it is too low-level for use on all MHs |
| throw newIllegalArgumentException("do not use this"); |
| } |
| |
| @Override |
| String internalProperties() { |
| return "\n& Class="+getClass().getSimpleName()+ |
| "\n& Target="+getTarget().debugString(); |
| } |
| |
| @Override |
| BoundMethodHandle rebind() { |
| return getTarget().rebind(); |
| } |
| |
| private static LambdaForm chooseDelegatingForm(MethodHandle target) { |
| if (target instanceof SimpleMethodHandle) |
| return target.internalForm(); // no need for an indirection |
| return makeReinvokerForm(target, MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, NF_getTarget); |
| } |
| |
| static LambdaForm makeReinvokerForm(MethodHandle target, |
| int whichCache, |
| Object constraint, |
| NamedFunction getTargetFn) { |
| String debugString; |
| switch(whichCache) { |
| case MethodTypeForm.LF_REBIND: debugString = "BMH.reinvoke"; break; |
| case MethodTypeForm.LF_DELEGATE: debugString = "MH.delegate"; break; |
| default: debugString = "MH.reinvoke"; break; |
| } |
| // No pre-action needed. |
| return makeReinvokerForm(target, whichCache, constraint, debugString, true, getTargetFn, null); |
| } |
| /** Create a LF which simply reinvokes a target of the given basic type. */ |
| static LambdaForm makeReinvokerForm(MethodHandle target, |
| int whichCache, |
| Object constraint, |
| String debugString, |
| boolean forceInline, |
| NamedFunction getTargetFn, |
| NamedFunction preActionFn) { |
| MethodType mtype = target.type().basicType(); |
| boolean customized = (whichCache < 0 || |
| mtype.parameterSlotCount() > MethodType.MAX_MH_INVOKER_ARITY); |
| boolean hasPreAction = (preActionFn != null); |
| LambdaForm form; |
| if (!customized) { |
| form = mtype.form().cachedLambdaForm(whichCache); |
| if (form != null) return form; |
| } |
| final int THIS_DMH = 0; |
| final int ARG_BASE = 1; |
| final int ARG_LIMIT = ARG_BASE + mtype.parameterCount(); |
| int nameCursor = ARG_LIMIT; |
| final int PRE_ACTION = hasPreAction ? nameCursor++ : -1; |
| final int NEXT_MH = customized ? -1 : nameCursor++; |
| final int REINVOKE = nameCursor++; |
| LambdaForm.Name[] names = LambdaForm.arguments(nameCursor - ARG_LIMIT, mtype.invokerType()); |
| assert(names.length == nameCursor); |
| names[THIS_DMH] = names[THIS_DMH].withConstraint(constraint); |
| Object[] targetArgs; |
| if (hasPreAction) { |
| names[PRE_ACTION] = new LambdaForm.Name(preActionFn, names[THIS_DMH]); |
| } |
| if (customized) { |
| targetArgs = Arrays.copyOfRange(names, ARG_BASE, ARG_LIMIT, Object[].class); |
| names[REINVOKE] = new LambdaForm.Name(target, targetArgs); // the invoker is the target itself |
| } else { |
| names[NEXT_MH] = new LambdaForm.Name(getTargetFn, names[THIS_DMH]); |
| targetArgs = Arrays.copyOfRange(names, THIS_DMH, ARG_LIMIT, Object[].class); |
| targetArgs[0] = names[NEXT_MH]; // overwrite this MH with next MH |
| names[REINVOKE] = new LambdaForm.Name(mtype, targetArgs); |
| } |
| form = new LambdaForm(debugString, ARG_LIMIT, names, forceInline); |
| if (!customized) { |
| form = mtype.form().setCachedLambdaForm(whichCache, form); |
| } |
| return form; |
| } |
| |
| static final NamedFunction NF_getTarget; |
| static { |
| try { |
| NF_getTarget = new NamedFunction(DelegatingMethodHandle.class |
| .getDeclaredMethod("getTarget")); |
| } catch (ReflectiveOperationException ex) { |
| throw newInternalError(ex); |
| } |
| } |
| } |