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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 io.microsphere.convert;
import io.microsphere.lang.Prioritized;
import java.util.ServiceLoader;
import static io.microsphere.reflect.TypeUtils.resolveActualTypeArgumentClass;
import static io.microsphere.util.ClassLoaderUtils.getClassLoader;
import static io.microsphere.util.ClassUtils.isAssignableFrom;
import static io.microsphere.util.ServiceLoaderUtils.loadServicesList;
/**
* A class to convert the source-typed value to the target-typed value
*
* @param The source type
* @param The target type
* @since 1.0.0
*/
@FunctionalInterface
public interface Converter extends Prioritized {
/**
* Accept the source type and target type or not
*
* @param sourceType the source type
* @param targetType the target type
* @return if accepted, return true, or false
*/
default boolean accept(Class sourceType, Class targetType) {
return isAssignableFrom(sourceType, getSourceType()) && isAssignableFrom(targetType, getTargetType());
}
/**
* Convert the source-typed value to the target-typed value
*
* @param source the source-typed value
* @return the target-typed value
*/
T convert(S source);
/**
* Get the source type
*
* @return non-null
*/
default Class getSourceType() {
return resolveActualTypeArgumentClass(getClass(), Converter.class, 0);
}
/**
* Get the target type
*
* @return non-null
*/
default Class getTargetType() {
return resolveActualTypeArgumentClass(getClass(), Converter.class, 1);
}
/**
* Get the Converter instance from {@link ServiceLoader} with the specified source and target type
*
* @param sourceType the source type
* @param targetType the target type
* @return
*/
static Converter getConverter(Class sourceType, Class targetType) {
ClassLoader classLoader = getClassLoader(Converter.class);
return loadServicesList(Converter.class, classLoader).stream()
.sorted()
.filter(converter -> converter.accept(sourceType, targetType)).findFirst().orElse(null);
}
/**
* Convert the value of source to target-type value if possible
*
* @param source the value of source
* @param targetType the target type
* @param the target type
* @return null if can't be converted
*/
static T convertIfPossible(Object source, Class targetType) {
Converter converter = getConverter(source.getClass(), targetType);
if (converter != null) {
return (T) converter.convert(source);
}
return null;
}
}