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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2018-2020 Payara Foundation and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://github.com/payara/Payara/blob/master/LICENSE.txt
* See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* The Payara Foundation designates this particular file as subject to the "Classpath"
* exception as provided by the Payara Foundation in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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package fish.payara.nucleus.microprofile.config.converters;
import org.eclipse.microprofile.config.inject.ConfigProperty;
import org.eclipse.microprofile.config.spi.Converter;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Stream;
/**
* Automatic {@link Converter}s are created "on the fly" in case no {@link Converter} as found but the target type has a
* suitable factory {@link Method} or {@link Constructor}.
*
* @author steve
*/
public class AutomaticConverter {
/**
* Return implicit converter for a class following section "Automatic Converters" of the spec, if class has
* matching construct
*
* @param generalType target type of property
* @param target type of property
* @return Optional of converter using a method found in the class, empty if none were found
*/
public static Optional> forType(Class type) {
return Stream.>>of(
() -> forMethod(type, "of", String.class),
() -> forMethod(type, "valueOf", String.class),
() -> forMethod(type, "parse", CharSequence.class),
() -> forConstructor(type, String.class))
.map(Supplier::get)
.filter(converter -> converter != null)
.findFirst();
}
private static final class MethodConverter implements Converter {
private final Method conversionMethod;
MethodConverter(Method conversionMethod) {
this.conversionMethod = conversionMethod;
}
@SuppressWarnings("unchecked")
@Override
public T convert(String value) {
if (value == null || value.equals(ConfigProperty.UNCONFIGURED_VALUE)) return null;
try {
return (T) conversionMethod.invoke(null, value);
} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
throw new IllegalArgumentException("Unable to convert value to type "
+ conversionMethod.getReturnType().getName() + " for value `" + value + "`", ex);
}
}
}
private static final class ConstructorConverter implements Converter {
private final Constructor constructor;
ConstructorConverter(Constructor constructor) {
this.constructor = constructor;
}
@Override
public T convert(String value) {
if (value == null || value.equals(ConfigProperty.UNCONFIGURED_VALUE)) return null;
try {
return constructor.newInstance(value);
} catch (InstantiationException | IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
throw new IllegalArgumentException("Unable to convert value to type "
+ constructor.getDeclaringClass().getName() + " for value `" + value + "`", ex);
}
}
}
private static Converter forMethod(Class type, String method, Class... argumentTypes) {
try {
Method factoryMethod = type.getMethod(method, argumentTypes);
if (Modifier.isStatic(factoryMethod.getModifiers())
&& Modifier.isPublic(factoryMethod.getModifiers())
&& factoryMethod.getReturnType() == type) {
return new MethodConverter<>(factoryMethod);
}
return null;
} catch (NoSuchMethodException | SecurityException e) {
return null;
}
}
private static Converter forConstructor(Class type, Class... argumentTypes) {
try {
Constructor constructor = type.getConstructor(argumentTypes);
if (Modifier.isPublic(constructor.getModifiers())) {
return new ConstructorConverter<>(constructor);
}
return null;
} catch (NoSuchMethodException | SecurityException e) {
return null;
}
}
}