jdk.internal.dynalink.support.Guards Java Examples

private MethodHandle getGuard(ValidationType validationType, MethodType methodType) {
    switch(validationType) {
        case EXACT_CLASS: {
            return getClassGuard(methodType);
        }
        case INSTANCE_OF: {
            return getAssignableGuard(methodType);
        }
        case IS_ARRAY: {
            return Guards.isArray(0, methodType);
        }
        case NONE: {
            return null;
        }
        default: {
            throw new AssertionError();
        }
    }
}
 

private MethodHandle getGuard(final ValidationType validationType, final MethodType methodType) {
    switch(validationType) {
        case EXACT_CLASS: {
            return getClassGuard(methodType);
        }
        case INSTANCE_OF: {
            return getAssignableGuard(methodType);
        }
        case IS_ARRAY: {
            return Guards.isArray(0, methodType);
        }
        case NONE: {
            return null;
        }
        default: {
            throw new AssertionError();
        }
    }
}
 

private GuardedInvocationComponent getLengthGetter(final CallSiteDescriptor callSiteDescriptor) {
    assertParameterCount(callSiteDescriptor, 1);
    final MethodType callSiteType = callSiteDescriptor.getMethodType();
    final Class<?> declaredType = callSiteType.parameterType(0);
    // If declared type of receiver at the call site is already an array, collection, or map, bind without guard.
    // Thing is, it'd be quite stupid of a call site creator to go though invokedynamic when it knows in advance
    // they're dealing with an array, collection, or map, but hey...
    if(declaredType.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType));
    } else if(Collection.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType));
    } else if(Map.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType));
    }

    // Otherwise, create a binding based on the actual type of the argument with an appropriate guard.
    if(clazz.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType), Guards.isArray(0,
                callSiteType), ValidationType.IS_ARRAY);
    } if(Collection.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType), Guards.asType(
                COLLECTION_GUARD, callSiteType), Collection.class, ValidationType.INSTANCE_OF);
    } if(Map.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType), Guards.asType(MAP_GUARD,
                callSiteType), Map.class, ValidationType.INSTANCE_OF);
    }
    // Can't retrieve length for objects that are neither arrays, nor collections, nor maps.
    return null;
}
 

boolean isVisibleFrom(final ClassLoader classLoader) {
    for(int i = 0; i < classes.length; ++i) {
        if(!Guards.canReferenceDirectly(classLoader, classes[i].getClassLoader())) {
            return false;
        }
    }
    return true;
}
 

BeanLinker(Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();
    Bootstrap.checkReflectionAccess(receiverClass);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass.getName());

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null);
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

BeanLinker(Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    }
}
 

boolean isVisibleFrom(final ClassLoader classLoader) {
    for(int i = 0; i < classes.length; ++i) {
        if(!Guards.canReferenceDirectly(classLoader, classes[i].getClassLoader())) {
            return false;
        }
    }
    return true;
}
 

BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();

    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        if (! Modifier.isPublic(receiverClass.getModifiers())) {
            throw ECMAErrors.typeError("new.on.nonpublic.javatype", receiverClass.getName());
        }

        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

private GuardedInvocationComponent getLengthGetter(CallSiteDescriptor callSiteDescriptor) {
    assertParameterCount(callSiteDescriptor, 1);
    final MethodType callSiteType = callSiteDescriptor.getMethodType();
    final Class<?> declaredType = callSiteType.parameterType(0);
    // If declared type of receiver at the call site is already an array, collection, or map, bind without guard.
    // Thing is, it'd be quite stupid of a call site creator to go though invokedynamic when it knows in advance
    // they're dealing with an array, collection, or map, but hey...
    if(declaredType.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType));
    } else if(Collection.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType));
    } else if(Map.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType));
    }

    // Otherwise, create a binding based on the actual type of the argument with an appropriate guard.
    if(clazz.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType), Guards.isArray(0,
                callSiteType), ValidationType.IS_ARRAY);
    } if(Collection.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType), Guards.asType(
                COLLECTION_GUARD, callSiteType), Collection.class, ValidationType.INSTANCE_OF);
    } if(Map.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType), Guards.asType(MAP_GUARD,
                callSiteType), Map.class, ValidationType.INSTANCE_OF);
    }
    // Can't retrieve length for objects that are neither arrays, nor collections, nor maps.
    return null;
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();

    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        if (! Modifier.isPublic(receiverClass.getModifiers())) {
            throw ECMAErrors.typeError("new.on.nonpublic.javatype", receiverClass.getName());
        }

        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

@Override
public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest, LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();
    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

boolean isVisibleFrom(final ClassLoader classLoader) {
    for(int i = 0; i < classes.length; ++i) {
        if(!Guards.canReferenceDirectly(classLoader, classes[i].getClassLoader())) {
            return false;
        }
    }
    return true;
}
 

BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();

    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        if (! Modifier.isPublic(receiverClass.getModifiers())) {
            throw ECMAErrors.typeError("new.on.nonpublic.javatype", receiverClass.getName());
        }

        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

private GuardedInvocationComponent getLengthGetter(final CallSiteDescriptor callSiteDescriptor) {
    assertParameterCount(callSiteDescriptor, 1);
    final MethodType callSiteType = callSiteDescriptor.getMethodType();
    final Class<?> declaredType = callSiteType.parameterType(0);
    // If declared type of receiver at the call site is already an array, collection, or map, bind without guard.
    // Thing is, it'd be quite stupid of a call site creator to go though invokedynamic when it knows in advance
    // they're dealing with an array, collection, or map, but hey...
    if(declaredType.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType));
    } else if(Collection.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType));
    } else if(Map.class.isAssignableFrom(declaredType)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType));
    }

    // Otherwise, create a binding based on the actual type of the argument with an appropriate guard.
    if(clazz.isArray()) {
        return new GuardedInvocationComponent(GET_ARRAY_LENGTH.asType(callSiteType), Guards.isArray(0,
                callSiteType), ValidationType.IS_ARRAY);
    } if(Collection.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_COLLECTION_LENGTH.asType(callSiteType), Guards.asType(
                COLLECTION_GUARD, callSiteType), Collection.class, ValidationType.INSTANCE_OF);
    } if(Map.class.isAssignableFrom(clazz)) {
        return new GuardedInvocationComponent(GET_MAP_LENGTH.asType(callSiteType), Guards.asType(MAP_GUARD,
                callSiteType), Map.class, ValidationType.INSTANCE_OF);
    }
    // Can't retrieve length for objects that are neither arrays, nor collections, nor maps.
    return null;
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

boolean isVisibleFrom(final ClassLoader classLoader) {
    for(int i = 0; i < classes.length; ++i) {
        if(!Guards.canReferenceDirectly(classLoader, classes[i].getClassLoader())) {
            return false;
        }
    }
    return true;
}
 

BeanLinker(final Class<?> clazz) {
    super(clazz, Guards.getClassGuard(clazz), Guards.getInstanceOfGuard(clazz));
    if(clazz.isArray()) {
        // Some languages won't have a notion of manipulating collections. Exposing "length" on arrays as an
        // explicit property is beneficial for them.
        // REVISIT: is it maybe a code smell that "dyn:getLength" is not needed?
        setPropertyGetter("length", GET_ARRAY_LENGTH, ValidationType.IS_ARRAY);
    } else if(List.class.isAssignableFrom(clazz)) {
        setPropertyGetter("length", GET_COLLECTION_LENGTH, ValidationType.INSTANCE_OF);
    }
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) {
    final Object receiver = linkRequest.getReceiver();
    if(!(receiver instanceof DynamicMethod)) {
        return null;
    }
    final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
    if(desc.getNameTokenCount() != 2 && desc.getNameToken(CallSiteDescriptor.SCHEME) != "dyn") {
        return null;
    }
    final String operator = desc.getNameToken(CallSiteDescriptor.OPERATOR);
    final DynamicMethod dynMethod = (DynamicMethod)receiver;
    final boolean constructor = dynMethod.isConstructor();
    final MethodHandle invocation;

    if (operator == "call" && !constructor) {
        invocation = dynMethod.getInvocation(
                CallSiteDescriptorFactory.dropParameterTypes(desc, 0, 1), linkerServices);
    } else if (operator == "new" && constructor) {
        final MethodHandle ctorInvocation = dynMethod.getInvocation(desc, linkerServices);
        if(ctorInvocation == null) {
            return null;
        }

        // Insert null for StaticClass parameter
        invocation = MethodHandles.insertArguments(ctorInvocation, 0, (Object)null);
    } else {
        return null;
    }

    if (invocation != null) {
        return new GuardedInvocation(MethodHandles.dropArguments(invocation, 0,
            desc.getMethodType().parameterType(0)), Guards.getIdentityGuard(receiver));
    }

    return null;
}
 

@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final LinkRequest request = linkRequest.withoutRuntimeContext(); // Nashorn has no runtime context
    final Object self = request.getReceiver();
    if (self.getClass() != StaticClass.class) {
        return null;
    }
    final Class<?> receiverClass = ((StaticClass) self).getRepresentedClass();

    Bootstrap.checkReflectionAccess(receiverClass, true);
    final CallSiteDescriptor desc = request.getCallSiteDescriptor();
    // We intercept "new" on StaticClass instances to provide additional capabilities
    if ("new".equals(desc.getNameToken(CallSiteDescriptor.OPERATOR))) {
        if (! Modifier.isPublic(receiverClass.getModifiers())) {
            throw ECMAErrors.typeError("new.on.nonpublic.javatype", receiverClass.getName());
        }

        // make sure new is on accessible Class
        Context.checkPackageAccess(receiverClass);

        // Is the class abstract? (This includes interfaces.)
        if (NashornLinker.isAbstractClass(receiverClass)) {
            // Change this link request into a link request on the adapter class.
            final Object[] args = request.getArguments();
            args[0] = JavaAdapterFactory.getAdapterClassFor(new Class<?>[] { receiverClass }, null,
                    linkRequest.getCallSiteDescriptor().getLookup());
            final LinkRequest adapterRequest = request.replaceArguments(request.getCallSiteDescriptor(), args);
            final GuardedInvocation gi = checkNullConstructor(delegate(linkerServices, adapterRequest), receiverClass);
            // Finally, modify the guard to test for the original abstract class.
            return gi.replaceMethods(gi.getInvocation(), Guards.getIdentityGuard(self));
        }
        // If the class was not abstract, just delegate linking to the standard StaticClass linker. Make an
        // additional check to ensure we have a constructor. We could just fall through to the next "return"
        // statement, except we also insert a call to checkNullConstructor() which throws an ECMAScript TypeError
        // with a more intuitive message when no suitable constructor is found.
        return checkNullConstructor(delegate(linkerServices, request), receiverClass);
    }
    // In case this was not a "new" operation, just delegate to the the standard StaticClass linker.
    return delegate(linkerServices, request);
}
 

private MethodHandle getAssignableGuard(final MethodType type) {
    return Guards.asType(assignableGuard, type);
}
 

private GuardedInvocationComponent getElementGetter(final CallSiteDescriptor callSiteDescriptor,
        final LinkerServices linkerServices, final List<String> operations) throws Exception {
    final MethodType callSiteType = callSiteDescriptor.getMethodType();
    final Class<?> declaredType = callSiteType.parameterType(0);
    final GuardedInvocationComponent nextComponent = getGuardedInvocationComponent(callSiteDescriptor,
            linkerServices, operations);

    // If declared type of receiver at the call site is already an array, a list or map, bind without guard. Thing
    // is, it'd be quite stupid of a call site creator to go though invokedynamic when it knows in advance they're
    // dealing with an array, or a list or map, but hey...
    // Note that for arrays and lists, using LinkerServices.asType() will ensure that any language specific linkers
    // in use will get a chance to perform any (if there's any) implicit conversion to integer for the indices.
    final GuardedInvocationComponent gic;
    final CollectionType collectionType;
    if(declaredType.isArray()) {
        gic = createInternalFilteredGuardedInvocationComponent(MethodHandles.arrayElementGetter(declaredType), linkerServices);
        collectionType = CollectionType.ARRAY;
    } else if(List.class.isAssignableFrom(declaredType)) {
        gic = createInternalFilteredGuardedInvocationComponent(GET_LIST_ELEMENT, linkerServices);
        collectionType = CollectionType.LIST;
    } else if(Map.class.isAssignableFrom(declaredType)) {
        gic = createInternalFilteredGuardedInvocationComponent(GET_MAP_ELEMENT, linkerServices);
        collectionType = CollectionType.MAP;
    } else if(clazz.isArray()) {
        gic = getClassGuardedInvocationComponent(linkerServices.filterInternalObjects(MethodHandles.arrayElementGetter(clazz)), callSiteType);
        collectionType = CollectionType.ARRAY;
    } else if(List.class.isAssignableFrom(clazz)) {
        gic = createInternalFilteredGuardedInvocationComponent(GET_LIST_ELEMENT, Guards.asType(LIST_GUARD, callSiteType), List.class, ValidationType.INSTANCE_OF,
                linkerServices);
        collectionType = CollectionType.LIST;
    } else if(Map.class.isAssignableFrom(clazz)) {
        gic = createInternalFilteredGuardedInvocationComponent(GET_MAP_ELEMENT, Guards.asType(MAP_GUARD, callSiteType), Map.class, ValidationType.INSTANCE_OF,
                linkerServices);
        collectionType = CollectionType.MAP;
    } else {
        // Can't retrieve elements for objects that are neither arrays, nor list, nor maps.
        return nextComponent;
    }

    // We can have "dyn:getElem:foo", especially in composites, i.e. "dyn:getElem|getProp|getMethod:foo"
    final String fixedKey = getFixedKey(callSiteDescriptor);
    // Convert the key to a number if we're working with a list or array
    final Object typedFixedKey;
    if(collectionType != CollectionType.MAP && fixedKey != null) {
        typedFixedKey = convertKeyToInteger(fixedKey, linkerServices);
        if(typedFixedKey == null) {
            // key is not numeric, it can never succeed
            return nextComponent;
        }
    } else {
        typedFixedKey = fixedKey;
    }

    final GuardedInvocation gi = gic.getGuardedInvocation();
    final Binder binder = new Binder(linkerServices, callSiteType, typedFixedKey);
    final MethodHandle invocation = gi.getInvocation();

    if(nextComponent == null) {
        return gic.replaceInvocation(binder.bind(invocation));
    }

    final MethodHandle checkGuard;
    switch(collectionType) {
    case LIST:
        checkGuard = convertArgToInt(RANGE_CHECK_LIST, linkerServices, callSiteDescriptor);
        break;
    case MAP:
        // TODO: A more complex solution could be devised for maps, one where we do a get() first, and fold it
        // into a GWT that tests if it returned null, and if it did, do another GWT with containsKey()
        // that returns constant null (on true), or falls back to next component (on false)
        checkGuard = linkerServices.filterInternalObjects(CONTAINS_MAP);
        break;
    case ARRAY:
        checkGuard = convertArgToInt(RANGE_CHECK_ARRAY, linkerServices, callSiteDescriptor);
        break;
    default:
        throw new AssertionError();
    }
    final MethodPair matchedInvocations = matchReturnTypes(binder.bind(invocation),
            nextComponent.getGuardedInvocation().getInvocation());
    return nextComponent.compose(matchedInvocations.guardWithTest(binder.bindTest(checkGuard)), gi.getGuard(),
            gic.getValidatorClass(), gic.getValidationType());
}
 

private static GuardedInvocation linkBean(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
    final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
    final Object self = linkRequest.getReceiver();
    final String operator = desc.getFirstOperator();
    switch (operator) {
    case "new":
        if(BeansLinker.isDynamicMethod(self)) {
            throw typeError("method.not.constructor", ScriptRuntime.safeToString(self));
        }
        throw typeError("not.a.function", ScriptRuntime.safeToString(self));
    case "call":
        // Support dyn:call on any object that supports some @FunctionalInterface
        // annotated interface. This way Java method, constructor references or
        // implementations of java.util.function.* interfaces can be called as though
        // those are script functions.
        final Method m = getFunctionalInterfaceMethod(self.getClass());
        if (m != null) {
            final MethodType callType = desc.getMethodType();
            // 'callee' and 'thiz' passed from script + actual arguments
            if (callType.parameterCount() != m.getParameterCount() + 2) {
                throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
            }
            return new GuardedInvocation(
                    // drop 'thiz' passed from the script.
                    MH.dropArguments(desc.getLookup().unreflect(m), 1, callType.parameterType(1)),
                    Guards.getInstanceOfGuard(m.getDeclaringClass())).asType(callType);
        }
        if(BeansLinker.isDynamicMethod(self)) {
            throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
        }
        throw typeError("not.a.function", ScriptRuntime.safeToString(self));
    case "callMethod":
    case "getMethod":
        throw typeError("no.such.function", getArgument(linkRequest), ScriptRuntime.safeToString(self));
    case "getProp":
    case "getElem":
        if (desc.getOperand() != null) {
            return getInvocation(EMPTY_PROP_GETTER, self, linkerServices, desc);
        }
        return getInvocation(EMPTY_ELEM_GETTER, self, linkerServices, desc);
    case "setProp":
    case "setElem":
        if (desc.getOperand() != null) {
            return getInvocation(EMPTY_PROP_SETTER, self, linkerServices, desc);
        }
        return getInvocation(EMPTY_ELEM_SETTER, self, linkerServices, desc);
    default:
        break;
    }
    throw new AssertionError("unknown call type " + desc);
}