--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dynalink/share/classes/jdk/dynalink/linker/GuardingTypeConverterFactory.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2010, 2013, 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file, and Oracle licenses the original version of this file under the BSD
+ * license:
+ */
+/*
+ Copyright 2009-2013 Attila Szegedi
+
+ Licensed under both the Apache License, Version 2.0 (the "Apache License")
+ and the BSD License (the "BSD License"), with licensee being free to
+ choose either of the two at their discretion.
+
+ You may not use this file except in compliance with either the Apache
+ License or the BSD License.
+
+ If you choose to use this file in compliance with the Apache License, the
+ following notice applies to you:
+
+ You may obtain a copy of the Apache License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied. See the License for the specific language governing
+ permissions and limitations under the License.
+
+ If you choose to use this file in compliance with the BSD License, the
+ following notice applies to you:
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are
+ met:
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ * Neither the name of the copyright holder nor the names of
+ contributors may be used to endorse or promote products derived from
+ this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
+ BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package jdk.dynalink.linker;
+
+import java.lang.invoke.MethodHandles;
+import java.util.function.Supplier;
+import jdk.dynalink.SecureLookupSupplier;
+import jdk.dynalink.beans.BeansLinker;
+import jdk.dynalink.linker.support.TypeUtilities;
+
+/**
+ * Optional interface that can be implemented by {@link GuardingDynamicLinker}
+ * implementations to provide language-specific type conversion capabilities.
+ * Note that if you implement this interface, you will very likely want to
+ * implement {@link ConversionComparator} interface too, as your additional
+ * language-specific conversions, in absence of a strategy for prioritizing
+ * these conversions, will cause more ambiguity for {@link BeansLinker} in
+ * selecting the correct overload when trying to link to an overloaded Java
+ * method.
+ */
+public interface GuardingTypeConverterFactory {
+ /**
+ * Returns a guarded type conversion that receives a value of the specified
+ * source type and returns a value converted to the specified target type.
+ * Value types can be either primitives or reference types, including
+ * interfaces, so you can even provide converters for converting your
+ * language's objects to Java interfaces and classes by generating adapters
+ * for them.
+ * <p>
+ * The type of the invocation is <code>(sourceType)→targetType</code>, while the
+ * type of the guard is <code>(sourceType)→boolean</code>. You are allowed to
+ * return unconditional invocations (with no guard) if the source type is
+ * specific to your runtime and your runtime only.
+ * <p>Note that this method will never be invoked for
+ * {@link TypeUtilities#isMethodInvocationConvertible(Class, Class) method
+ * invocation conversions} as those can be automatically applied by
+ * {@link java.lang.invoke.MethodHandle#asType(MethodType)}.
+ * An implementation can assume it is never requested to produce a
+ * converter for those conversions. If a language runtime needs to customize
+ * method invocation conversions, it should
+ * {@link jdk.dynalink.DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)
+ * set an autoconversion strategy in the dynamic linker factory} instead.
+ * <p>Dynalink is at liberty to either cache some of the returned converters
+ * or to repeatedly request the converter factory to create the same
+ * conversion.
+ *
+ * @param sourceType source type
+ * @param targetType the target type.
+ * @param lookupSupplier a supplier for retrieving the lookup of the class
+ * on whose behalf a type converter is requested. When a converter is
+ * requested as part of linking an {@code invokedynamic} instruction the
+ * supplier will return the lookup passed to the bootstrap method, otherwise
+ * if the method is invoked from within a
+ * {@link LinkerServices#getWithLookup(Supplier, jdk.dynalink.SecureLookupSupplier)}
+ * it will delegate to the secure lookup supplier. In any other case,
+ * it will return the public lookup. A typical case where the lookup might
+ * be needed is when the converter creates a Java adapter class on the fly
+ * (e.g. to convert some object from the dynamic language into a Java
+ * interface for interoperability). Invoking the {@link Supplier#get()}
+ * method on the passed supplier will be subject to the same security checks
+ * as {@link SecureLookupSupplier#getLookup()}. An implementation should avoid
+ * retrieving the lookup if it is not needed so as to avoid the expense of
+ * {@code AccessController.doPrivileged} call.
+ * @return a guarded invocation that can take an object (if it passes guard)
+ * and return another object that is its representation coerced into the
+ * target type. In case the factory is certain it is unable to handle a
+ * conversion, it can return null. In case the factory is certain that it
+ * can always handle the conversion, it can return an unconditional
+ * invocation (one whose guard is null).
+ * @throws Exception if there was an error during creation of the converter
+ * @see LinkerServices#getWithLookup(Supplier, SecureLookupSupplier)
+ */
+ public GuardedInvocation convertToType(Class<?> sourceType, Class<?> targetType, Supplier<MethodHandles.Lookup> lookupSupplier) throws Exception;
+}