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Jenetics - Java Genetic Algorithm Library
There is a newer version: 3.6.0
/*
 * Java Genetic Algorithm Library (jenetics-3.1.0).
 * Copyright (c) 2007-2015 Franz Wilhelmstötter
 *
 * 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.
 *
 * Author:
 *    Franz Wilhelmstötter ([email protected])
 */
package org.jenetics.internal.util;

import static org.jenetics.internal.util.reflect.classOf;
import static org.jenetics.internal.util.reflect.innerClasses;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.function.Function;

import javax.xml.bind.DataBindingException;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.annotation.adapters.XmlAdapter;

import org.jenetics.internal.util.model.CharacterModel;

/**
 * JAXB helper methods.
 *
 * @author Franz Wilhelmstötter
 * @version 1.6
 * @since 2.0
 */
public class jaxb {
	private jaxb() {require.noInstance();}

	private static final class JAXBContextHolder {
		private static final JAXBContext CONTEXT; static {
			try {
				CONTEXT = JAXBContext.newInstance(
					"org.jenetics:org.jenetics.internal.util"
				);
			} catch (JAXBException e) {
				throw new DataBindingException(
					"Something went wrong while creating JAXBContext.", e
				);
			}
		}
	}

	public static JAXBContext context() {
		return JAXBContextHolder.CONTEXT;
	}

	private static final XmlAdapter IDENTITY_ADAPTER =
		new XmlAdapter() {
			@Override public Object unmarshal(final Object value) {
				return value;
			}
			@Override public Object marshal(final Object value) {
				return value;
			}
		};

	private static final ConcurrentMap, XmlAdapter> ADAPTERS =
		new ConcurrentHashMap<>();

	static {
		ADAPTERS.put(Character.class, CharacterModel.ADAPTER);
		ADAPTERS.put(CharacterModel.class, CharacterModel.ADAPTER);
	}

	/**
	 * Return the an {@code XmlAdapter} for the given {@code vale}. If no
	 * adapter could be found, and identity adapter is returned.
	 *
	 * @param value the object for which to find an {@code XmlAdapter}
	 * @return the {@code XmlAdapter} for the given object, or an identity
	 *         adapter if no one can be found.
	 */
	@SuppressWarnings("unchecked")
	public static XmlAdapter adapterFor(final Object value) {
		return (XmlAdapter)ADAPTERS
			.computeIfAbsent(classOf(value), jaxb::newXmlAdapter);
	}

	private static XmlAdapter newXmlAdapter(final Class cls) {
		return innerClasses(cls)
			.filter(XmlAdapter.class::isAssignableFrom)
			.findFirst()
			.flatMap(reflect::>newInstance)
			.orElse(IDENTITY_ADAPTER);
	}

	/**
	 * Shorthand for {@code adapterFor(value).marshal(value)}
	 */
	public static Object marshal(final Object value) throws Exception {
		return adapterFor(value).marshal(value);
	}

	/**
	 * Shorthand for {@code adapterFor(value).unmarshal(value)}
	 */
	public static Object unmarshal(final Object value) throws Exception {
		return adapterFor(value).unmarshal(value);
	}

	/**
	 * Return a marshaller function from the given
	 * {@link javax.xml.bind.annotation.adapters.XmlAdapter}.
	 *
	 * @param a the adapter used by the marshaller function.
	 * @return the marshaller function
	 */
	public static  Function Marshaller(final XmlAdapter a) {
		return value -> {
			try {
				return a.marshal(value);
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		};
	}

	/**
	 * Return a unmarshaller function from the given
	 * {@link javax.xml.bind.annotation.adapters.XmlAdapter}.
	 *
	 * @param a the adapter used by the unmarshaller function.
	 * @return the unmarshaller function
	 */
	public static  Function Unmarshaller(final XmlAdapter a) {
		return value -> {
			try {
				return a.unmarshal(value);
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		};
	}

	/**
	 * Return a marshaller function for the given object.
	 *
	 * @param value the value to marshal
	 * @return the marshaller function
	 */
	public static Function Marshaller(final Object value) {
		return Marshaller(adapterFor(value));
	}

	/**
	 * Return a unmarshaller function for the given object.
	 *
	 * @param value the value to unmarshal
	 * @return the unmarshaller function
	 */
	public static Function Unmarshaller(final Object value)  {
		return Unmarshaller(jaxb.adapterFor(value));
	}

}