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ProxyFactory.java
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ProxyFactory.java
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/*
* MIT License
*
* Copyright (c) 2020 Uladzislau Seuruk
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.github.vladislavsevruk.generator.proxy;
import com.github.vladislavsevruk.generator.proxy.source.compiler.JavaSourceCompiler;
import com.github.vladislavsevruk.generator.proxy.source.generator.ProxySourceCodeGenerator;
import com.github.vladislavsevruk.generator.proxy.source.loader.JavaByteClassLoader;
import com.github.vladislavsevruk.generator.proxy.source.schema.ProxyClassSchema;
import com.github.vladislavsevruk.resolver.resolver.executable.ExecutableTypeMetaResolver;
import com.github.vladislavsevruk.resolver.resolver.executable.ExecutableTypeResolver;
import com.github.vladislavsevruk.resolver.type.TypeMeta;
import lombok.extern.log4j.Log4j2;
import java.lang.reflect.AnnotatedType;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.BiPredicate;
import java.util.stream.Collectors;
/**
* Factory for dynamic generation of proxies with custom behavior.
*
* @param <T> type of target class.
*/
@Log4j2
public final class ProxyFactory<T> {
private static final Map<String, Class<?>> RESOLVED_CLASSES = new ConcurrentHashMap<>();
private final Class<T> clazz;
private final ExecutableTypeResolver<TypeMeta<?>> executableTypeResolver = new ExecutableTypeMetaResolver();
private final ProxyClassSchema proxyClassSchema;
private final ProxySourceCodeGenerator proxyContentGenerator;
public ProxyFactory(Class<T> clazz, ProxySourceCodeGenerator proxyContentGenerator) {
this(clazz, proxyContentGenerator, "");
}
public ProxyFactory(Class<T> clazz, ProxySourceCodeGenerator proxyContentGenerator, String proxyClassPrefix) {
this.clazz = clazz;
this.proxyContentGenerator = proxyContentGenerator;
this.proxyClassSchema = new ProxyClassSchema(clazz, proxyClassPrefix);
}
/**
* Returns constructor of proxy or initial class if proxy generation failed that matches received parameter types.
*
* @param args argument types to pick matching constructor for.
* @return constructor of generated proxy or initial class if proxy generation failed.
* @throws IllegalArgumentException if received argument types doesn't match any public constructor of initial
* class.
*/
@SuppressWarnings("java:S1452")
public Constructor<? extends T> getConstructor(Class<?>... args) {
return getConstructor(getProxyClass(), args);
}
/**
* Creates new instance of proxy or initial class if proxy generation failed.
*
* @param args arguments to be passed as arguments to the constructor call.
* @return instance of generated proxy or initial class if proxy generation failed.
* @throws IllegalArgumentException if received arguments doesn't match any public constructor of initial class.
*/
public T newInstance(Object... args) {
Class<?>[] receivedParameterTypes = Arrays.stream(args).map(arg -> arg == null ? null : arg.getClass())
.toArray(Class<?>[]::new);
return createInstance(getProxyClass(), receivedParameterTypes, args);
}
private static boolean isAlreadyCompiled(String name) {
return RESOLVED_CLASSES.containsKey(name);
}
@SuppressWarnings("unchecked")
private Class<? extends T> compileClass(String proxyClassName, String proxyClassContent) {
return (Class<? extends T>) Optional.ofNullable(JavaSourceCompiler.compile(proxyClassName, proxyClassContent))
.map(compiledByteFileObject -> JavaByteClassLoader.instance()
.defineClass(proxyClassName, compiledByteFileObject)).orElse(null);
}
private T createInstance(Class<? extends T> clazzToCreate, Class<?>[] receivedParameterTypes, Object[] args) {
try {
return getConstructor(clazzToCreate, receivedParameterTypes).newInstance(args);
} catch (InstantiationException | IllegalAccessException | InvocationTargetException ex) {
log.warn(String.format("Failed to create '%s' instance by constructor with %s args.",
clazzToCreate.getName(), Arrays.asList(receivedParameterTypes)), ex);
return null;
}
}
@SuppressWarnings("unchecked")
private Constructor<? extends T> getConstructor(Class<? extends T> clazzToCreate,
Class<?>[] receivedParameterTypes) {
log.debug("Picking '{}' constructor for {} parameters.", clazzToCreate.getName(),
Arrays.asList(receivedParameterTypes));
Constructor<?> firstFoundCandidate = null;
for (Constructor<?> constructor : clazzToCreate.getConstructors()) {
List<TypeMeta<?>> typeMetas = executableTypeResolver.getParameterTypes(clazzToCreate, constructor);
if (isExactMatchingParameters(typeMetas, receivedParameterTypes)) {
logExactMatchingConstructor(typeMetas);
return (Constructor<? extends T>) constructor;
}
if (firstFoundCandidate == null && isMatchingParameters(typeMetas, receivedParameterTypes)) {
firstFoundCandidate = constructor;
}
}
if (firstFoundCandidate != null) {
logPickedMatchingConstructor(firstFoundCandidate);
return (Constructor<? extends T>) firstFoundCandidate;
}
throw new IllegalArgumentException(String.format("There is no public constructor for args %s at %s class.",
Arrays.asList(receivedParameterTypes), clazz.getName()));
}
@SuppressWarnings("unchecked")
private Class<? extends T> getProxyClass() {
if (Modifier.isFinal(clazz.getModifiers())) {
log.warn("'{}' class is final.", clazz.getName());
return clazz;
}
String proxyClassName = String.format("%s.%s", proxyClassSchema.getPackage(), proxyClassSchema.getName());
if (!isAlreadyCompiled(proxyClassName)) {
String proxyClassContent = proxyContentGenerator.generate(proxyClassSchema);
Class<? extends T> compiledClass = compileClass(proxyClassName, proxyClassContent);
Class<? extends T> resultedClass = compiledClass != null ? compiledClass : clazz;
RESOLVED_CLASSES.put(proxyClassName, resultedClass);
}
return (Class<? extends T>) RESOLVED_CLASSES.get(proxyClassName);
}
private boolean isAllMatchCondition(List<TypeMeta<?>> typeMetas, Class<?>[] receivedParameterTypes,
BiPredicate<TypeMeta<?>, Class<?>> condition) {
if (typeMetas.size() != receivedParameterTypes.length) {
return false;
}
for (int i = 0; i < typeMetas.size(); ++i) {
if (condition.test(typeMetas.get(i), receivedParameterTypes[i])) {
return false;
}
}
return true;
}
private boolean isExactMatchingParameters(List<TypeMeta<?>> typeMetas, Class<?>[] receivedParameterTypes) {
return isAllMatchCondition(typeMetas, receivedParameterTypes,
(typeMeta, parameterType) -> !typeMeta.getType().equals(parameterType));
}
private boolean isMatchingParameters(List<TypeMeta<?>> typeMetas, Class<?>[] receivedParameterTypes) {
return isAllMatchCondition(typeMetas, receivedParameterTypes,
(typeMeta, parameterType) -> parameterType != null && !typeMeta.getType()
.isAssignableFrom(parameterType));
}
private void logExactMatchingConstructor(List<TypeMeta<?>> typeMetas) {
log.debug(() -> {
String parameterTypes = typeMetas.stream().map(TypeMeta::getType).map(Class::getName)
.collect(Collectors.joining(", "));
return String.format("Found constructor with [%s] parameters.", parameterTypes);
});
}
private void logPickedMatchingConstructor(Constructor<?> firstFoundCandidate) {
log.debug(() -> {
String parameterTypes = Arrays.stream(firstFoundCandidate.getAnnotatedParameterTypes())
.map(AnnotatedType::getType).map(Type::getTypeName).collect(Collectors.joining(", "));
return String.format("Picked constructor with [%s] parameters.", parameterTypes);
});
}
}