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/*
 *  Copyright Technophobia Ltd 2012
 *
 *   This file is part of Substeps.
 *
 *    Substeps is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    Substeps is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with Substeps.  If not, see .
 */
package com.technophobia.substeps.execution;

import com.google.common.base.Functions;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.Maps;
import com.technophobia.substeps.model.exception.SubstepsRuntimeException;

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

/*
 *  Copyright Technophobia Ltd 2012
 *
 *   This file is part of Substeps.
 *
 *    Substeps is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    Substeps is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with Substeps.  If not, see .
 */
public class ImplementationCache implements MethodExecutor {

    protected final Map, Object> instanceMap;

    public ImplementationCache() {
        instanceMap = Maps.newHashMap();
    }

    @Override
    public void addImplementationClasses(final Class... implementationClasses) {

        if (implementationClasses != null) {
            for (final Class implementationClass : implementationClasses) {
                if (!instanceMap.containsKey(implementationClass)) {
                    instanceMap.put(implementationClass, instantiate(implementationClass));
                }
            }
        }
    }


    /**
     * constructs a class with zero args constructor.  If the class is an inner class, traverse up the hierarchy instantiate the enclosing classes
     * @param clazz the class to be constructed
     * @return
     * @throws IllegalAccessException
     * @throws InstantiationException
     * @throws InvocationTargetException
     */
    private static Object instantiateClass(final Class clazz) throws IllegalAccessException, InstantiationException, InvocationTargetException {

        Class enclosingClass = clazz.getEnclosingClass();

        if (clazz.getConstructors()[0].getParameterCount() > 0 && enclosingClass != null){

            Object value = instantiateClass(enclosingClass);
            return clazz.getConstructors()[0].newInstance(value);
        }
        else {
            return clazz.newInstance();
        }
    }

    private Object instantiate(final Class implementationClass) {

        try {
            return instantiateClass(implementationClass);
        } catch (final InstantiationException ex) {
            throw new IllegalStateException("Could not create instance of " + implementationClass, ex);
        } catch (final IllegalAccessException ex) {
            throw new IllegalStateException("Could not create instance of " + implementationClass, ex);
        } catch (InvocationTargetException ex) {
            throw new IllegalStateException("Could not create instance of " + implementationClass, ex);
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * com.technophobia.substeps.execution.MethodExecutor#executeMethods(java
     * .util.List)
     */
    @Override
    public void executeMethods(final List methods) {

        for (final Method method : methods) {

            // TODO - curious about the findSuitableInstancesOf ? won't
            // method.getDeclaringClass be ok??

            for (final Object object : findSuitableInstancesOf(method.getDeclaringClass())) {
                try {
                    method.invoke(object);
                }
                catch (Exception e){
                    throw new SubstepsRuntimeException(e);
                }
            }
        }
    }

    private Collection