/*
    *  Copyright 2010, 2011 Chris Pheby
    *
    *  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.jadira.bindings.core.general.unmarshaller;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Modifier;
  
  import org.jadira.bindings.core.api.BindingException;
  import org.jadira.bindings.core.api.FromUnmarshaller;
  
  /**
   * Unmarshaller supports constructor parameterised by a target object
   * @param <S> Source type for the conversion
   * @param <T> Target type
   */
  public final class ConstructorFromUnmarshaller<S, T> implements FromUnmarshaller<S, T> {
  
      private final Constructor<S> unmarshal;
  
      private final Class<S> boundClass;
      
      private final Class<T> targetClass;
      
      /**
       * Create a new instance
       * @param unmarshal Constructor to be used
       */
      public ConstructorFromUnmarshaller(Constructor<S> unmarshal) {
          
          this.boundClass = unmarshal.getDeclaringClass();
          
          if (getBoundClass().isInterface() 
                  || Modifier.isAbstract(getBoundClass().getModifiers()) 
                  || getBoundClass().isLocalClass() 
                  || getBoundClass().isMemberClass()) {
              throw new IllegalStateException("unmarshal constructor must have an instantiable target class");
          }
          
          if (unmarshal.getParameterTypes().length != 1) {
          	throw new IllegalStateException("unmarshal constructor must have a single parameter");
          }
          
          this.unmarshal = unmarshal;
          
          @SuppressWarnings("unchecked")
          Class<T> myTarget = (Class<T>)unmarshal.getParameterTypes()[0];
          this.targetClass = myTarget;
      }
  
  	/**
  	 * {@inheritDoc}
  	 */
  	/* @Override */
      public S unmarshal(T object) {
      	
      	if (object != null && !targetClass.isAssignableFrom(object.getClass())) {
      		throw new IllegalArgumentException("Supplied object was not instance of target class");
      	}
      	
          try {
              return unmarshal.newInstance(object);
          } catch (IllegalAccessException ex) {
              throw new IllegalStateException("Constructor is not accessible");
          } catch (InstantiationException ex) {
              throw new IllegalStateException("Constructor is not valid");
          } catch (InvocationTargetException ex) {
              if (ex.getCause() instanceof RuntimeException) {
                  throw (RuntimeException) ex.getCause();
              }
              throw new BindingException(ex.getMessage(), ex.getCause());
          }
      }
      
  	/**
  	 * {@inheritDoc}
  	 */
  	/* @Override */
      public Class<S> getBoundClass() {
          return boundClass;
      }
      
  	/**
  	 * {@inheritDoc}
  	 */
  	/* @Override */
     public Class<T> getTargetClass() {
         return targetClass;
     }
 }