8144519: Add a sample for pluggable dynalink linker that demonstrats beans linker delegation
Reviewed-by: mhaupt, jlaskey
This commit is contained in:
parent
90a60b04c7
commit
11d29f7c6c
@ -1,2 +1,3 @@
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DOMLinkerExporter
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UnderscoreNameLinkerExporter
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MissingMethodLinkerExporter
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53
nashorn/samples/MissingMethodExample.java
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53
nashorn/samples/MissingMethodExample.java
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/*
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of Oracle nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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import java.util.ArrayList;
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// This is an example class that implements MissingMethodHandler
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// to receive "doesNotUnderstand" calls on 'missing methods'
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public class MissingMethodExample extends ArrayList
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implements MissingMethodHandler {
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@Override
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public Object doesNotUnderstand(String name, Object... args) {
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// This dummy doesNotUnderstand just prints method name and args.
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// You can put useful method routing logic here.
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System.out.println("you called " + name);
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if (args.length != 0) {
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System.out.println("arguments are: ");
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for (Object arg : args) {
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System.out.println(" " + arg);
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}
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}
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return this;
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}
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}
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37
nashorn/samples/MissingMethodHandler.java
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37
nashorn/samples/MissingMethodHandler.java
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/*
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of Oracle nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// interface to be implemented by any Java class that wants
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// to trap "missing method" calls.
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public interface MissingMethodHandler {
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// name is "missing" method name. "args" is the array of arguments passed
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public Object doesNotUnderstand(String name, Object... args);
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}
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190
nashorn/samples/MissingMethodLinkerExporter.java
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190
nashorn/samples/MissingMethodLinkerExporter.java
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/*
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of Oracle nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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import java.lang.invoke.MethodHandle;
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import java.lang.invoke.MethodHandles;
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import java.lang.invoke.MethodType;
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import java.util.ArrayList;
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import java.util.List;
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import jdk.dynalink.CallSiteDescriptor;
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import jdk.dynalink.CompositeOperation;
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import jdk.dynalink.NamedOperation;
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import jdk.dynalink.Operation;
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import jdk.dynalink.StandardOperation;
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import jdk.dynalink.beans.BeansLinker;
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import jdk.dynalink.linker.GuardingDynamicLinker;
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import jdk.dynalink.linker.GuardingDynamicLinkerExporter;
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import jdk.dynalink.linker.GuardedInvocation;
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import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
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import jdk.dynalink.linker.LinkRequest;
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import jdk.dynalink.linker.LinkerServices;
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import jdk.dynalink.linker.support.Guards;
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import jdk.dynalink.linker.support.Lookup;
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/**
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* This is a dynalink pluggable linker (see http://openjdk.java.net/jeps/276).
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* This linker routes missing methods to Smalltalk-style doesNotUnderstand method.
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* Object of any Java class that implements MissingMethodHandler is handled by this linker.
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* For any method call, if a matching Java method is found, it is called. If there is no
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* method by that name, then MissingMethodHandler.doesNotUnderstand is called.
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*/
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public final class MissingMethodLinkerExporter extends GuardingDynamicLinkerExporter {
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static {
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System.out.println("pluggable dynalink missing method linker loaded");
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}
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// represents a MissingMethod - just stores as name and also serves a guard type
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public static class MissingMethod {
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private final String name;
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public MissingMethod(String name) {
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this.name = name;
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}
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public String getName() {
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return name;
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}
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}
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// MissingMethodHandler.doesNotUnderstand method
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private static final MethodHandle DOES_NOT_UNDERSTAND;
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// type of MissingMethodHandler - but "this" and String args are flipped
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private static final MethodType FLIPPED_DOES_NOT_UNDERSTAND_TYPE;
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// "is this a MissingMethod?" guard
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private static final MethodHandle IS_MISSING_METHOD;
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// MissingMethod object->it's name filter
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private static final MethodHandle MISSING_METHOD_TO_NAME;
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static {
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DOES_NOT_UNDERSTAND = Lookup.PUBLIC.findVirtual(
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MissingMethodHandler.class,
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"doesNotUnderstand",
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MethodType.methodType(Object.class, String.class, Object[].class));
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FLIPPED_DOES_NOT_UNDERSTAND_TYPE =
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MethodType.methodType(Object.class, String.class, MissingMethodHandler.class, Object[].class);
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IS_MISSING_METHOD = Guards.isOfClass(MissingMethod.class,
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MethodType.methodType(Boolean.TYPE, Object.class));
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MISSING_METHOD_TO_NAME = Lookup.PUBLIC.findVirtual(MissingMethod.class,
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"getName", MethodType.methodType(String.class));
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}
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// locate the first standard operation from the call descriptor
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private static StandardOperation getFirstStandardOperation(final CallSiteDescriptor desc) {
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final Operation base = NamedOperation.getBaseOperation(desc.getOperation());
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if (base instanceof StandardOperation) {
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return (StandardOperation)base;
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} else if (base instanceof CompositeOperation) {
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final CompositeOperation cop = (CompositeOperation)base;
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for(int i = 0; i < cop.getOperationCount(); ++i) {
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final Operation op = cop.getOperation(i);
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if (op instanceof StandardOperation) {
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return (StandardOperation)op;
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}
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}
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}
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return null;
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}
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@Override
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public List<GuardingDynamicLinker> get() {
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final ArrayList<GuardingDynamicLinker> linkers = new ArrayList<>();
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final BeansLinker beansLinker = new BeansLinker();
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linkers.add(new TypeBasedGuardingDynamicLinker() {
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// only handles MissingMethodHandler and MissingMethod objects
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@Override
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public boolean canLinkType(final Class<?> type) {
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return
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MissingMethodHandler.class.isAssignableFrom(type) ||
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type == MissingMethod.class;
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}
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@Override
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public GuardedInvocation getGuardedInvocation(LinkRequest request,
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LinkerServices linkerServices) throws Exception {
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final Object self = request.getReceiver();
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CallSiteDescriptor desc = request.getCallSiteDescriptor();
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// any method call is done by two steps. Step (1) GET_METHOD and (2) is CALL
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// For step (1), we check if GET_METHOD can succeed by Java linker, if so
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// we return that method object. If not, we return a MissingMethod object.
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if (self instanceof MissingMethodHandler) {
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// Check if this is a named GET_METHOD first.
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boolean isGetMethod = getFirstStandardOperation(desc) == StandardOperation.GET_METHOD;
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Object name = NamedOperation.getName(desc.getOperation());
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if (isGetMethod && name instanceof String) {
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GuardingDynamicLinker javaLinker = beansLinker.getLinkerForClass(self.getClass());
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GuardedInvocation inv;
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try {
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inv = javaLinker.getGuardedInvocation(request, linkerServices);
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} catch (final Throwable th) {
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inv = null;
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}
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String nameStr = name.toString();
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if (inv == null) {
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// use "this" for just guard and drop it -- return a constant Method handle
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// that returns a newly created MissingMethod object
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MethodHandle mh = MethodHandles.constant(Object.class, new MissingMethod(nameStr));
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inv = new GuardedInvocation(
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MethodHandles.dropArguments(mh, 0, Object.class),
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Guards.isOfClass(self.getClass(), MethodType.methodType(Boolean.TYPE, Object.class)));
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}
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return inv;
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}
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} else if (self instanceof MissingMethod) {
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// This is step (2). We call MissingMethodHandler.doesNotUnderstand here
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// Check if this is this a CALL first.
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boolean isCall = getFirstStandardOperation(desc) == StandardOperation.CALL;
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if (isCall) {
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MethodHandle mh = DOES_NOT_UNDERSTAND;
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// flip "this" and method name (String)
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mh = MethodHandles.permuteArguments(mh, FLIPPED_DOES_NOT_UNDERSTAND_TYPE, 1, 0, 2);
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// collect rest of the arguments as vararg
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mh = mh.asCollector(Object[].class, desc.getMethodType().parameterCount() - 2);
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// convert MissingMethod object to it's name
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mh = MethodHandles.filterArguments(mh, 0, MISSING_METHOD_TO_NAME);
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return new GuardedInvocation(mh, IS_MISSING_METHOD);
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}
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}
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return null;
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}
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});
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return linkers;
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}
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}
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51
nashorn/samples/missing_method.js
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51
nashorn/samples/missing_method.js
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# Usage: jjs -cp missing_method_linker.js missing_method.js
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/*
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of Oracle nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// MissingMethodExample class extends ArrayList and
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// implements MissingMethodHandler interface
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var MME = Java.type("MissingMethodExample")
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var obj = new MME()
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// can call any ArrayList method
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obj.add("hello")
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obj.add("world")
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print(obj.size())
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print(obj)
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// "foo", "bar" are 'missing' methods
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// these will result in doesNotUnderstand calls
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obj.foo(1, "www", true)
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obj.bar("http", "dynalink")
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// another valid ArrayList method call
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obj.forEach(print)
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49
nashorn/samples/missing_method_linker.js
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49
nashorn/samples/missing_method_linker.js
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@ -0,0 +1,49 @@
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#! missing method linker example
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/*
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* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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||||
* 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.
|
||||
*
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||||
* - Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
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||||
* documentation and/or other materials provided with the distribution.
|
||||
*
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* - 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,
|
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
|
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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// This script assumes you've built jdk9 or using latest
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// jdk9 image and put the 'bin' directory in the PATH
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$EXEC.throwOnError=true
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// compile MissingMethodLinkerExporter
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`javac -cp ../dist/nashorn.jar MissingMethodLinkerExporter.java MissingMethodHandler.java MissingMethodExample.java`
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// make a jar file out of pluggable linker
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`jar cvf missing_method_linker.jar MissingMethod*.class META-INF/`
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// run a sample script that uses pluggable linker
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// but make sure classpath points to the pluggable linker jar!
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`jjs -cp missing_method_linker.jar missing_method.js`
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print($OUT)
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