--- /dev/null 2015-12-08 13:32:15.000000000 +0530 +++ new/samples/ArrayStreamLinkerExporter.java 2015-12-08 13:32:15.275269000 +0530 @@ -0,0 +1,124 @@ +/* + * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. + * + * 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 Oracle nor the names of its + * 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 THE COPYRIGHT OWNER OR + * CONTRIBUTORS 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. + */ + +import java.lang.invoke.MethodHandle; +import java.lang.invoke.MethodHandles; +import java.lang.invoke.MethodType; +import java.util.ArrayList; +import java.util.List; +import java.util.stream.DoubleStream; +import java.util.stream.IntStream; +import java.util.stream.LongStream; +import java.util.stream.Stream; +import jdk.dynalink.CallSiteDescriptor; +import jdk.dynalink.CompositeOperation; +import jdk.dynalink.NamedOperation; +import jdk.dynalink.Operation; +import jdk.dynalink.StandardOperation; +import jdk.dynalink.linker.GuardingDynamicLinker; +import jdk.dynalink.linker.GuardingDynamicLinkerExporter; +import jdk.dynalink.linker.GuardedInvocation; +import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker; +import jdk.dynalink.linker.LinkRequest; +import jdk.dynalink.linker.LinkerServices; +import jdk.dynalink.linker.support.Guards; +import jdk.dynalink.linker.support.Lookup; + +/** + * This is a dynalink pluggable linker (see http://openjdk.java.net/jeps/276). + * This linker adds "stream" property to Java arrays. The appropriate Stream + * type object is returned for "stream" property on Java arrays. Note that + * the dynalink beans linker just adds "length" property and Java array objects + * don't have any other property. "stream" property does not conflict with anything + * else! + */ +public final class ArrayStreamLinkerExporter extends GuardingDynamicLinkerExporter { + static { + System.out.println("pluggable dynalink array stream linker loaded"); + } + + public static Object arrayToStream(Object array) { + if (array instanceof int[]) { + return IntStream.of((int[])array); + } else if (array instanceof long[]) { + return LongStream.of((long[])array); + } else if (array instanceof double[]) { + return DoubleStream.of((double[])array); + } else if (array instanceof Object[]) { + return Stream.of((Object[])array); + } else { + throw new IllegalArgumentException(); + } + } + + private static final MethodType GUARD_TYPE = MethodType.methodType(Boolean.TYPE, Object.class); + private static final MethodHandle ARRAY_TO_STREAM = Lookup.PUBLIC.findStatic( + ArrayStreamLinkerExporter.class, "arrayToStream", + MethodType.methodType(Object.class, Object.class)); + + @Override + public List get() { + final ArrayList linkers = new ArrayList<>(); + linkers.add(new TypeBasedGuardingDynamicLinker() { + @Override + public boolean canLinkType(final Class type) { + return type == Object[].class || type == int[].class || + type == long[].class || type == double[].class; + } + + @Override + public GuardedInvocation getGuardedInvocation(LinkRequest request, + LinkerServices linkerServices) throws Exception { + final Object self = request.getReceiver(); + if (self == null || !canLinkType(self.getClass())) { + return null; + } + + CallSiteDescriptor desc = request.getCallSiteDescriptor(); + Operation op = desc.getOperation(); + Object name = NamedOperation.getName(op); + boolean getProp = CompositeOperation.contains( + NamedOperation.getBaseOperation(op), + StandardOperation.GET_PROPERTY); + if (getProp && name instanceof String) { + String nameStr = (String)name; + if (nameStr.equals("stream")) { + return new GuardedInvocation(ARRAY_TO_STREAM, + Guards.isOfClass(self.getClass(), GUARD_TYPE)); + } + } + + return null; + } + }); + return linkers; + } +}