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microBean™ Invoke: Functional and invokedynamic constructs for Java
/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
*
* Copyright © 2022 microBean™.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package org.microbean.invoke;
import java.lang.constant.ClassDesc;
import java.lang.invoke.ConstantCallSite;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandles.Lookup;
import java.lang.invoke.MethodType;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Map;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;
/**
* Useful constant bootstrap methods and methods that make sense to
* invoke from {@link
* java.lang.invoke.ConstantBootstraps#invoke(Lookup, String, Class,
* MethodHandle, Object...)}.
*
* @author Laird Nelson
*
* @see java.lang.invoke
*/
public final class BootstrapMethods {
/*
* Constructors.
*/
private BootstrapMethods() {
super();
}
/*
* public static methods.
*/
public static final ConstantCallSite findStaticSetterCallSite(final Lookup lookup,
final String fieldName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return new ConstantCallSite(findStaticSetterMethodHandle(lookup, fieldName, methodType.parameterType(0), targetClass));
}
public static final ConstantCallSite findStaticCallSiteAsSpreader(final Lookup lookup,
final String methodName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return new ConstantCallSite(findStaticMethodHandle(lookup, methodName, methodType, targetClass)
.asSpreader(Object[].class, methodType.parameterCount()));
}
public static final ConstantCallSite findSetterCallSite(final Lookup lookup,
final String fieldName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return new ConstantCallSite(findSetterMethodHandle(lookup, fieldName, methodType.parameterType(0), targetClass));
}
public static final ConstantCallSite findVirtualCallSite(final Lookup lookup,
final String methodName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return new ConstantCallSite(findVirtualMethodHandle(lookup, methodName, methodType, targetClass));
}
public static final ConstantCallSite findConstructorCallSite(final Lookup lookup,
final String ignoredMethodName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return new ConstantCallSite(findConstructorMethodHandle(lookup, methodType, targetClass));
}
@SuppressWarnings("unchecked")
public static final SortedMap immutableSortedMapOf(final Map map,
final Comparator comparator) {
final SortedMap mutableSortedMap;
if (comparator == null) {
if (map instanceof SortedMap) {
mutableSortedMap = (SortedMap)map;
} else {
mutableSortedMap = new TreeMap<>(map);
}
} else {
mutableSortedMap = new TreeMap<>(comparator);
mutableSortedMap.putAll(map);
}
return Collections.unmodifiableSortedMap(mutableSortedMap);
}
@SuppressWarnings("unchecked")
public static final SortedSet immutableSortedSetOf(final Collection set,
final Comparator comparator) {
final SortedSet mutableSortedSet;
if (comparator == null) {
if (set instanceof SortedSet) {
mutableSortedSet = (SortedSet)set;
} else {
mutableSortedSet = new TreeSet<>(set);
}
} else {
mutableSortedSet = new TreeSet<>(comparator);
mutableSortedSet.addAll(set);
}
return Collections.unmodifiableSortedSet(mutableSortedSet);
}
/*
* private static methods.
*/
private static final MethodHandle findStaticMethodHandle(final Lookup lookup,
final String methodName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return MethodHandles.privateLookupIn(targetClass, lookup).findStatic(targetClass, methodName, methodType);
}
private static final MethodHandle findStaticSetterMethodHandle(final Lookup lookup,
final String fieldName,
final Class fieldType,
final Class targetClass)
throws Throwable {
return
MethodHandles.privateLookupIn(targetClass, lookup).findStaticSetter(targetClass, fieldName, fieldType);
}
private static final MethodHandle findSetterMethodHandle(final Lookup lookup,
final String fieldName,
final Class fieldType,
final Class targetClass)
throws Throwable {
return
MethodHandles.privateLookupIn(targetClass, lookup).findSetter(targetClass, fieldName, fieldType);
}
private static final MethodHandle findVirtualMethodHandle(final Lookup lookup,
final String methodName,
final MethodType methodType,
final Class targetClass)
throws Throwable {
return MethodHandles.privateLookupIn(targetClass, lookup).findVirtual(targetClass, methodName, methodType);
}
private static final MethodHandle findConstructorMethodHandle(final Lookup lookup,
final MethodType methodType,
final Class targetClass)
throws Throwable {
if (void.class != methodType.returnType()) {
throw new IllegalArgumentException("void.class != methodType.returnType(); methodType: " + methodType);
}
return MethodHandles.privateLookupIn(targetClass, lookup).findConstructor(targetClass, methodType);
}
}