DefaultBootstrapper.java

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/*
   Copyright 2009-2013 Attila Szegedi

   Licensed under both the Apache License, Version 2.0 (the "Apache License")
   and the BSD License (the "BSD License"), with licensee being free to
   choose either of the two at their discretion.

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   License or the BSD License.

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           http://www.apache.org/licenses/LICENSE-2.0

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       distributed under the License is distributed on an "AS IS" BASIS,
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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package jdk.internal.dynalink;

import java.lang.invoke.CallSite;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import jdk.internal.dynalink.support.CallSiteDescriptorFactory;

/**
 * A convenience default bootstrapper that exposes static bootstrap methods which language runtimes that need the very
 * default behavior can use with minimal setup. When first referenced, it will create a dynamic linker with default
 * settings for the {@link DynamicLinkerFactory}, and its bootstrap methods will create {@link MonomorphicCallSite} for
 * all call sites. It has two bootstrap methods: one creates call sites that use the
 * {@link MethodHandles#publicLookup()} as the lookup for all call sites and disregard the one passed in as the caller,
 * and one that just uses the passed caller as the lookup scope. Using the public lookup one is advised if your language
 * runtime has no concept of interacting with Java visibility scopes, as it results in a more lightweight runtime
 * information.
 *
 * @author Attila Szegedi
 */
public class DefaultBootstrapper {
    private static final DynamicLinker dynamicLinker = new DynamicLinkerFactory().createLinker();

    private DefaultBootstrapper() {
    }

    /**
     * Use this method as your bootstrap method (see the documentation of the java.lang.invoke package for how to do
     * this). In case your language runtime doesn't have a concept of interaction with Java access scopes, you might
     * want to consider using
     * {@link #publicBootstrap(java.lang.invoke.MethodHandles.Lookup, String, MethodType)} instead.
     *
     * @param caller the caller's lookup
     * @param name the name of the method at the call site
     * @param type the method signature at the call site
     * @return a new {@link MonomorphicCallSite} linked with the default dynamic linker.
     */
    public static CallSite bootstrap(final MethodHandles.Lookup caller, final String name, final MethodType type) {
        return bootstrapInternal(caller, name, type);
    }

    /**
     * Use this method as your bootstrap method (see the documentation of the java.lang.invoke package for how to do
     * this) when your language runtime doesn't have a concept of interaction with Java access scopes. If you need to
     * preserve the different caller Lookup objects in the call sites, use
     * {@link #bootstrap(java.lang.invoke.MethodHandles.Lookup, String, MethodType)} instead
     *
     * @param caller the caller's lookup. It is ignored as the call sites will be created with
     * {@link MethodHandles#publicLookup()} instead.
     * @param name the name of the method at the call site
     * @param type the method signature at the call site
     * @return a new {@link MonomorphicCallSite} linked with the default dynamic linker.
     */
    public static CallSite publicBootstrap(final MethodHandles.Lookup caller, final String name, final MethodType type) {
        return bootstrapInternal(MethodHandles.publicLookup(), name, type);
    }

    private static CallSite bootstrapInternal(final MethodHandles.Lookup caller, final String name, final MethodType type) {
        return dynamicLinker.link(new MonomorphicCallSite(CallSiteDescriptorFactory.create(caller, name, type)));
    }
}