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package org.nakedobjects.metamodel.util;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.nakedobjects.applib.ApplicationException;
import org.nakedobjects.metamodel.commons.exceptions.NakedObjectApplicationException;
import org.nakedobjects.metamodel.commons.lang.WrapperUtils;
import org.nakedobjects.metamodel.exceptions.ReflectionException;
import org.nakedobjects.metamodel.specloader.internal.introspector.MethodFinderUtils;


/**
 * TODO: remove duplication with {@link WrapperUtils} and {@link MethodFinderUtils}.
 */
public class InvokeUtils {

	
    // //////////////////////////////////////////////////////////////
    // invoke
    // //////////////////////////////////////////////////////////////

    public static void invoke(final List methods, final Object object) {
    	for(Method method: methods) {
    		invoke(method, object);
    	}
    }

    public static Object invoke(final Method method, final Object object) {
    	final Object[] parameters = nullOrDefaultArgsFor(method);
        return invoke(method, object, parameters);
    }
    
    public static Object invoke(final Method method, final Object object, final Object[] parameters) {
        try {
            return method.invoke(object, parameters);
        } catch (final InvocationTargetException e) {
            invocationException("Exception executing " + method, e);
            return null;
        } catch (final IllegalAccessException e) {
            throw new ReflectionException("illegal access of " + method, e);
        }
    }

    // //////////////////////////////////////////////////////////////
    // invokeStatic
    // //////////////////////////////////////////////////////////////

    public static Object invokeStatic(final Method method, final Object[] parameters) {
        return invoke(method, null, parameters);
    }

    public static Object invokeStatic(final Method method) {
    	return invoke(method, null, nullOrDefaultArgsFor(method));
    }

    
    // //////////////////////////////////////////////////////////////
    // invocationException
    // //////////////////////////////////////////////////////////////

    public static void invocationException(final String error, final InvocationTargetException e) {
        final Throwable targetException = e.getTargetException();
        if (targetException instanceof ApplicationException) {
            // an application exception from the domain code is re-thrown as an NO exception with same
            // semantics
            throw new NakedObjectApplicationException(targetException);
        }
        if (targetException instanceof RuntimeException) {
            throw (RuntimeException) targetException;
        } else {
            throw new ReflectionException(targetException);
        }
    }


    // //////////////////////////////////////////////////////////////
    // Helpers
    // //////////////////////////////////////////////////////////////

    private static Map,Object> defaultByPrimitiveType = new HashMap, Object>();
    static {
        defaultByPrimitiveType.put(byte.class, (byte) 0);
        defaultByPrimitiveType.put(short.class, (short) 0);
        defaultByPrimitiveType.put(int.class, 0);
        defaultByPrimitiveType.put(long.class, 0L);
        defaultByPrimitiveType.put(char.class, 0);
        defaultByPrimitiveType.put(float.class, 0.0F);
        defaultByPrimitiveType.put(double.class, 0.0);
        defaultByPrimitiveType.put(boolean.class, false);
    }


    private static Object[] nullOrDefaultArgsFor(final Method method) {
        final Class[] paramTypes = method.getParameterTypes();
        final Object[] parameters = new Object[paramTypes.length];
        for (int i = 0; i < parameters.length; i++) {
            parameters[i] = nullOrDefaultFor(paramTypes[i]);
        }
        return parameters;
    }

    /**
     * Returns the corresponding 'null' value for the primitives, or just null if the class
     * represents a non-primitive type.
     */
    private static Object nullOrDefaultFor(final Class type) {
        return defaultByPrimitiveType.get(type);
    }


}