8144519: Add a sample for pluggable dynalink linker that demonstrats beans linker delegation

Reviewed-by: mhaupt, jlaskey
This commit is contained in:
Athijegannathan Sundararajan 2015-12-03 19:04:39 +05:30
parent 90a60b04c7
commit 11d29f7c6c
6 changed files with 381 additions and 0 deletions

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DOMLinkerExporter
UnderscoreNameLinkerExporter
MissingMethodLinkerExporter

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/*
* 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.util.ArrayList;
// This is an example class that implements MissingMethodHandler
// to receive "doesNotUnderstand" calls on 'missing methods'
public class MissingMethodExample extends ArrayList
implements MissingMethodHandler {
@Override
public Object doesNotUnderstand(String name, Object... args) {
// This dummy doesNotUnderstand just prints method name and args.
// You can put useful method routing logic here.
System.out.println("you called " + name);
if (args.length != 0) {
System.out.println("arguments are: ");
for (Object arg : args) {
System.out.println(" " + arg);
}
}
return this;
}
}

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/*
* 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.
*/
// interface to be implemented by any Java class that wants
// to trap "missing method" calls.
public interface MissingMethodHandler {
// name is "missing" method name. "args" is the array of arguments passed
public Object doesNotUnderstand(String name, Object... args);
}

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/*
* 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 jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.CompositeOperation;
import jdk.dynalink.NamedOperation;
import jdk.dynalink.Operation;
import jdk.dynalink.StandardOperation;
import jdk.dynalink.beans.BeansLinker;
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 routes missing methods to Smalltalk-style doesNotUnderstand method.
* Object of any Java class that implements MissingMethodHandler is handled by this linker.
* For any method call, if a matching Java method is found, it is called. If there is no
* method by that name, then MissingMethodHandler.doesNotUnderstand is called.
*/
public final class MissingMethodLinkerExporter extends GuardingDynamicLinkerExporter {
static {
System.out.println("pluggable dynalink missing method linker loaded");
}
// represents a MissingMethod - just stores as name and also serves a guard type
public static class MissingMethod {
private final String name;
public MissingMethod(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
// MissingMethodHandler.doesNotUnderstand method
private static final MethodHandle DOES_NOT_UNDERSTAND;
// type of MissingMethodHandler - but "this" and String args are flipped
private static final MethodType FLIPPED_DOES_NOT_UNDERSTAND_TYPE;
// "is this a MissingMethod?" guard
private static final MethodHandle IS_MISSING_METHOD;
// MissingMethod object->it's name filter
private static final MethodHandle MISSING_METHOD_TO_NAME;
static {
DOES_NOT_UNDERSTAND = Lookup.PUBLIC.findVirtual(
MissingMethodHandler.class,
"doesNotUnderstand",
MethodType.methodType(Object.class, String.class, Object[].class));
FLIPPED_DOES_NOT_UNDERSTAND_TYPE =
MethodType.methodType(Object.class, String.class, MissingMethodHandler.class, Object[].class);
IS_MISSING_METHOD = Guards.isOfClass(MissingMethod.class,
MethodType.methodType(Boolean.TYPE, Object.class));
MISSING_METHOD_TO_NAME = Lookup.PUBLIC.findVirtual(MissingMethod.class,
"getName", MethodType.methodType(String.class));
}
// locate the first standard operation from the call descriptor
private static StandardOperation getFirstStandardOperation(final CallSiteDescriptor desc) {
final Operation base = NamedOperation.getBaseOperation(desc.getOperation());
if (base instanceof StandardOperation) {
return (StandardOperation)base;
} else if (base instanceof CompositeOperation) {
final CompositeOperation cop = (CompositeOperation)base;
for(int i = 0; i < cop.getOperationCount(); ++i) {
final Operation op = cop.getOperation(i);
if (op instanceof StandardOperation) {
return (StandardOperation)op;
}
}
}
return null;
}
@Override
public List<GuardingDynamicLinker> get() {
final ArrayList<GuardingDynamicLinker> linkers = new ArrayList<>();
final BeansLinker beansLinker = new BeansLinker();
linkers.add(new TypeBasedGuardingDynamicLinker() {
// only handles MissingMethodHandler and MissingMethod objects
@Override
public boolean canLinkType(final Class<?> type) {
return
MissingMethodHandler.class.isAssignableFrom(type) ||
type == MissingMethod.class;
}
@Override
public GuardedInvocation getGuardedInvocation(LinkRequest request,
LinkerServices linkerServices) throws Exception {
final Object self = request.getReceiver();
CallSiteDescriptor desc = request.getCallSiteDescriptor();
// any method call is done by two steps. Step (1) GET_METHOD and (2) is CALL
// For step (1), we check if GET_METHOD can succeed by Java linker, if so
// we return that method object. If not, we return a MissingMethod object.
if (self instanceof MissingMethodHandler) {
// Check if this is a named GET_METHOD first.
boolean isGetMethod = getFirstStandardOperation(desc) == StandardOperation.GET_METHOD;
Object name = NamedOperation.getName(desc.getOperation());
if (isGetMethod && name instanceof String) {
GuardingDynamicLinker javaLinker = beansLinker.getLinkerForClass(self.getClass());
GuardedInvocation inv;
try {
inv = javaLinker.getGuardedInvocation(request, linkerServices);
} catch (final Throwable th) {
inv = null;
}
String nameStr = name.toString();
if (inv == null) {
// use "this" for just guard and drop it -- return a constant Method handle
// that returns a newly created MissingMethod object
MethodHandle mh = MethodHandles.constant(Object.class, new MissingMethod(nameStr));
inv = new GuardedInvocation(
MethodHandles.dropArguments(mh, 0, Object.class),
Guards.isOfClass(self.getClass(), MethodType.methodType(Boolean.TYPE, Object.class)));
}
return inv;
}
} else if (self instanceof MissingMethod) {
// This is step (2). We call MissingMethodHandler.doesNotUnderstand here
// Check if this is this a CALL first.
boolean isCall = getFirstStandardOperation(desc) == StandardOperation.CALL;
if (isCall) {
MethodHandle mh = DOES_NOT_UNDERSTAND;
// flip "this" and method name (String)
mh = MethodHandles.permuteArguments(mh, FLIPPED_DOES_NOT_UNDERSTAND_TYPE, 1, 0, 2);
// collect rest of the arguments as vararg
mh = mh.asCollector(Object[].class, desc.getMethodType().parameterCount() - 2);
// convert MissingMethod object to it's name
mh = MethodHandles.filterArguments(mh, 0, MISSING_METHOD_TO_NAME);
return new GuardedInvocation(mh, IS_MISSING_METHOD);
}
}
return null;
}
});
return linkers;
}
}

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# Usage: jjs -cp missing_method_linker.js missing_method.js
/*
* 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.
*/
// MissingMethodExample class extends ArrayList and
// implements MissingMethodHandler interface
var MME = Java.type("MissingMethodExample")
var obj = new MME()
// can call any ArrayList method
obj.add("hello")
obj.add("world")
print(obj.size())
print(obj)
// "foo", "bar" are 'missing' methods
// these will result in doesNotUnderstand calls
obj.foo(1, "www", true)
obj.bar("http", "dynalink")
// another valid ArrayList method call
obj.forEach(print)

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#! missing method linker example
/*
* 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.
*/
// This script assumes you've built jdk9 or using latest
// jdk9 image and put the 'bin' directory in the PATH
$EXEC.throwOnError=true
// compile MissingMethodLinkerExporter
`javac -cp ../dist/nashorn.jar MissingMethodLinkerExporter.java MissingMethodHandler.java MissingMethodExample.java`
// make a jar file out of pluggable linker
`jar cvf missing_method_linker.jar MissingMethod*.class META-INF/`
// run a sample script that uses pluggable linker
// but make sure classpath points to the pluggable linker jar!
`jjs -cp missing_method_linker.jar missing_method.js`
print($OUT)