ArrayStreamLinkerExporter.java revision 1565:c779bd47d648 
1/*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 *   - Redistributions of source code must retain the above copyright
9 *     notice, this list of conditions and the following disclaimer.
10 *
11 *   - Redistributions in binary form must reproduce the above copyright
12 *     notice, this list of conditions and the following disclaimer in the
13 *     documentation and/or other materials provided with the distribution.
14 *
15 *   - Neither the name of Oracle nor the names of its
16 *     contributors may be used to endorse or promote products derived
17 *     from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32import java.lang.invoke.MethodHandle;
33import java.lang.invoke.MethodHandles;
34import java.lang.invoke.MethodType;
35import java.util.ArrayList;
36import java.util.List;
37import java.util.stream.DoubleStream;
38import java.util.stream.IntStream;
39import java.util.stream.LongStream;
40import java.util.stream.Stream;
41import jdk.dynalink.CallSiteDescriptor;
42import jdk.dynalink.CompositeOperation;
43import jdk.dynalink.NamedOperation;
44import jdk.dynalink.Operation;
45import jdk.dynalink.StandardOperation;
46import jdk.dynalink.linker.GuardingDynamicLinker;
47import jdk.dynalink.linker.GuardingDynamicLinkerExporter;
48import jdk.dynalink.linker.GuardedInvocation;
49import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
50import jdk.dynalink.linker.LinkRequest;
51import jdk.dynalink.linker.LinkerServices;
52import jdk.dynalink.linker.support.Guards;
53import jdk.dynalink.linker.support.Lookup;
54
55/**
56 * This is a dynalink pluggable linker (see http://openjdk.java.net/jeps/276).
57 * This linker adds "stream" property to Java arrays. The appropriate Stream
58 * type object is returned for "stream" property on Java arrays. Note that
59 * the dynalink beans linker just adds "length" property and Java array objects
60 * don't have any other property. "stream" property does not conflict with anything
61 * else!
62 */
63public final class ArrayStreamLinkerExporter extends GuardingDynamicLinkerExporter {
64    static {
65        System.out.println("pluggable dynalink array stream linker loaded");
66    }
67
68    public static Object arrayToStream(Object array) {
69        if (array instanceof int[]) {
70            return IntStream.of((int[])array);
71        } else if (array instanceof long[]) {
72            return LongStream.of((long[])array);
73        } else if (array instanceof double[]) {
74            return DoubleStream.of((double[])array);
75        } else if (array instanceof Object[]) {
76            return Stream.of((Object[])array);
77        } else {
78            throw new IllegalArgumentException();
79        }
80    }
81
82    private static final MethodType GUARD_TYPE = MethodType.methodType(Boolean.TYPE, Object.class);
83    private static final MethodHandle ARRAY_TO_STREAM = Lookup.PUBLIC.findStatic(
84            ArrayStreamLinkerExporter.class, "arrayToStream",
85            MethodType.methodType(Object.class, Object.class));
86
87    @Override
88    public List<GuardingDynamicLinker> get() {
89        final ArrayList<GuardingDynamicLinker> linkers = new ArrayList<>();
90        linkers.add(new TypeBasedGuardingDynamicLinker() {
91            @Override
92            public boolean canLinkType(final Class<?> type) {
93                return type == Object[].class || type == int[].class ||
94                       type == long[].class || type == double[].class;
95            }
96
97            @Override
98            public GuardedInvocation getGuardedInvocation(LinkRequest request,
99                LinkerServices linkerServices) throws Exception {
100                final Object self = request.getReceiver();
101                if (self == null || !canLinkType(self.getClass())) {
102                    return null;
103                }
104
105                CallSiteDescriptor desc = request.getCallSiteDescriptor();
106                Operation op = desc.getOperation();
107                Object name = NamedOperation.getName(op);
108                boolean getProp = CompositeOperation.contains(
109                        NamedOperation.getBaseOperation(op),
110                        StandardOperation.GET_PROPERTY);
111                if (getProp && "stream".equals(name)) {
112                    return new GuardedInvocation(ARRAY_TO_STREAM,
113                        Guards.isOfClass(self.getClass(), GUARD_TYPE));
114                }
115
116                return null;
117            }
118        });
119        return linkers;
120    }
121}
122