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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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 * only the GPL Version 2, indicate your decision by adding "[Contributor]
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 */

package com.sun.faces.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.logging.Logger;
import java.util.logging.Level;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.beans.PropertyDescriptor;
import java.beans.Introspector;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import static java.beans.Introspector.getBeanInfo;
import java.beans.PropertyEditor;
import static java.beans.PropertyEditorManager.findEditor;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;

/**
 * A set of utility methods to make working with
 * Classes and Reflection a little easier.
 */
public final class ReflectionUtils {

    private static final Logger LOGGER = FacesLogger.APPLICATION.getLogger();

    /**
     * Cache
     */
    private static final Map> REFLECTION_CACHE =
          new WeakHashMap<>();


    // ------------------------------------------------------------ Constructors


    private ReflectionUtils() { }


    // ---------------------------------------------------------- Public Methods
    
        
	/**
	 * Sets a collection of properties of a given object to the values associated with those properties.
	 * 
	 * In the map that represents these properties, each key represents the name of the property, with the value
	 * associated with that key being the value that is set for the property.
	 * 

	 * E.g. map entry key = foo, value = "bar", which "bar" an instance of String, will conceptually result in the
	 * following call: object.setFoo("string");
	 *
	 * 

	 * NOTE: This particular method assumes that there's a write method for each property in the map with the right
	 * type. No specific checking is done whether this is indeed the case.
	 *
	 * @param object
	 *            the object on which properties will be set
	 * @param propertiesToSet
	 *            the map containing properties and their values to be set on the object
	 */
	public static void setProperties(Object object, Map propertiesToSet) {

	  try {
			Map availableProperties = new HashMap<>();
			for (PropertyDescriptor propertyDescriptor : getBeanInfo(object.getClass()).getPropertyDescriptors()) {
				availableProperties.put(propertyDescriptor.getName(), propertyDescriptor);
			}

			for (Map.Entry propertyToSet : propertiesToSet.entrySet()) {
				availableProperties.get(propertyToSet.getKey()).getWriteMethod().invoke(object, propertyToSet.getValue());
			}

		} catch (IntrospectionException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
			throw new IllegalStateException(e);
		}
	}

	/**
	 * Sets a collection of properties of a given object to the (optionally coerced) values associated with those properties.
	 * 

	 * In the map that represents these properties, each key represents the name of the property, with the value
	 * associated with that key being the value that is set for the property.
	 * 

	 * E.g. map entry key = foo, value = "bar", which "bar" an instance of String, will conceptually result in the
	 * following call: object.setFoo("string");
	 *
	 * 

	 * NOTE 1: In case the value is a String, and the target type is not String, the standard property editor mechanism
	 * will be used to attempt a conversion.
	 *
	 * 

	 * Note 2: This method operates somewhat as the reverse of {@link Reflection#setProperties(Object, Map)}. Here only
	 * the available writable properties of the object are matched against the map with properties to set. Properties
	 * in the map for which there isn't a corresponding writable property on the object are ignored.
	 *
	 * 

	 * Following the above two notes, use this method when attempting to set properties on an object in a lenient best effort
	 * basis. Use {@link Reflection#setProperties(Object, Map)} when all properties need to be set with the exact type as the value
	 * appears in the map.
	 *
	 *
	 * @param object
	 *            the object on which properties will be set
	 * @param propertiesToSet
	 *            the map containing properties and their values to be set on the object
	 */
	public static void setPropertiesWithCoercion(Object object, Map propertiesToSet) {
		try {
			for (PropertyDescriptor property : getBeanInfo(object.getClass()).getPropertyDescriptors()) {
				Method setter = property.getWriteMethod();

				if (setter == null) {
					continue;
				}

				if (propertiesToSet.containsKey(property.getName())) {

					Object value = propertiesToSet.get(property.getName());
					if (value instanceof String && !property.getPropertyType().equals(String.class)) {

						// Try to convert Strings to the type expected by the converter

						PropertyEditor editor = findEditor(property.getPropertyType());
						editor.setAsText((String) value);
						value = editor.getValue();
					}

					property.getWriteMethod().invoke(object, value);
				}

			}
		} catch (Exception e) { // NOPMD
			throw new IllegalStateException(e);
		}
	}

	/**
	 * Finds a method based on the method name, amount of parameters and limited typing, if necessary prefixed with "get".
	 * 

	 * Note that this supports overloading, but a limited one. Given an actual parameter of type Long, this will select
	 * a method accepting Number when the choice is between Number and a non-compatible type like String. However,
	 * it will NOT select the best match if the choice is between Number and Long.
	 *
	 * @param base the object in which the method is to be found
	 * @param methodName name of the method to be found
	 * @param params the method parameters
	 * @return a method if one is found, null otherwise
	 */
	public static Method findMethod(Object base, String methodName, Object[] params) {

		List methods = new ArrayList<>();
		for (Method method : base.getClass().getMethods()) {
			if (method.getName().equals(methodName) && method.getParameterTypes().length == params.length) {
				methods.add(method);
			}
		}

		if (methods.size() == 1) {
			return methods.get(0);
		}

		if (methods.size() > 1) {
			// Overloaded methods were found. Try to get a match
			for (Method method : methods) {
				boolean match = true;
				Class[] candidateParams = method.getParameterTypes();
				for (int i = 0; i < params.length; i++) {
					if (!candidateParams[i].isInstance(params[i])) {
						match = false;
						break;
					}
				}

				// If all candidate parameters were expected and for none of them the actual
				// parameter was NOT an instance, we have a match
				if (match) {
					return method;
				}

				// Else, at least one parameter was not an instance
				// Go ahead a test then next methods
			}
		}

		return null;
	}

	/**
	 * Returns the Class instance associated with the class of the given string, using the context class
	 * loader and if that fails the defining class loader of the current class.
	 *
	 * @param className fully qualified class name of the class for which a Class instance needs to be created
	 * @return the Class object for the class with the given name.
	 * @throws IllegalStateException if the class cannot be found.
	 */
	public static Class toClass(String className) {
		try {
			return (Class.forName(className, true, Thread.currentThread().getContextClassLoader()));
		}
		catch (ClassNotFoundException e) {
			try {
				return Class.forName(className);
			}
			catch (Exception ignore) {
				ignore = null; // Just continue to IllegalStateException on original ClassNotFoundException.
			}

			throw new IllegalStateException(e);
		}
	}

	/**
	 * Creates an instance of a class with the given fully qualified class name.
	 *
	 * @param  The generic object type.
	 * @param className fully qualified class name of the class for which an instance needs to be created
	 * @return an instance of the class denoted by className
	 * @throws IllegalStateException if the class cannot be found
	 */
	@SuppressWarnings("unchecked")
	public static  T instance(String className) {
		return (T) instance(toClass(className));
	}

	/**
	 * Creates a new instance of the class represented by the given Class object
	 *
	 * @param  The generic object type.
	 * @param clazz the Class object for which an instance needs to be created
	 * @return an instance of the class as given by the clazz parameter
	 * @throws IllegalStateException if the class cannot be found, or cannot be instantiated or when a security manager prevents this operation
	 */
	public static  T instance(Class clazz) {
		try {
			return clazz.newInstance();
		} catch (InstantiationException | IllegalAccessException e) {
			throw new IllegalStateException(e);
		}
	}

    /**
     * 
Clears the cache for the specified ClassLoader.
     * This method MUST be called when ConfigureListener
     * .contextDestroyed() is called.
     * @param loader the ClassLoader whose associated cache
     *  should be cleared
     */
    public static synchronized void clearCache(ClassLoader loader) {

            REFLECTION_CACHE.remove(loader);

    }


    public static synchronized void initCache(ClassLoader loader) {

        if (REFLECTION_CACHE.get(loader) == null) {
            REFLECTION_CACHE.put(loader,
                                 new ConcurrentHashMap<>());
        }

    }


    /**
     * Returns the Constructor appropriate to the specified
     * Class and parameters.
     * @param clazz the Class of interest
     * @param params the parameters for the constructor of the provided Class
     * @return a Constructor that can be invoked with the specified parameters
     */
    public static Constructor lookupConstructor(
          Class clazz,
          Class... params) {

        ClassLoader loader = Util.getCurrentLoader(clazz);
        if (loader == null) {
            return null;
        }
        
        return getMetaData(loader, clazz).lookupConstructor(params);
        
    }
    
    /**
     * Returns the Method appropriate to the specified
     * Class, method name, and parameters.
     * @param clazz the Class of interest
     * @param methodName the name of the method
     * @param params the parameters for the specified method
     * @return a Method that can be invoked with the specified parameters
     */
    public static Method lookupMethod(
          Class clazz,
          String methodName,
          Class... params) {

        ClassLoader loader = Util.getCurrentLoader(clazz);
        if (loader == null) {
            return null;
        }        
        
        return getMetaData(loader, clazz).lookupMethod(methodName, params);
        
    }


    /**
     * Constructs a new object instance based off the
     * provided class name.
     * @param className the class of the object to instantiate
     * @return a new instances of said class
     * @throws InstantiationException if the class cannot be instantiated
     * @throws IllegalAccessException if there is a security violation
     */
    public static Object newInstance(String className)
    throws InstantiationException, IllegalAccessException {

        ClassLoader loader = Util.getCurrentLoader(null);
        if (loader == null) {
            return null;
        }

        return getMetaData(loader, className).lookupClass().newInstance();
        
    }


    /**
     * Obtain a Class instance based on the provided
     * String name.
     * @param className the class to look up
     * @return the Class corresponding to className
     */
    public static Class lookupClass(String className) {

        ClassLoader loader = Util.getCurrentLoader(null);
        if (loader == null) {
            return null;
        }

        return getMetaData(loader, className).lookupClass();
        
    }


    /**
     * @param className the fully qualified class name
     * @param propertyName a JavaBeans property name
     * @return a method suitable for setting a JavaBeans property, or
     *  null if the property doesn't exist or is readonly.
     */
    public static Method lookupWriteMethod(String className, String propertyName) {

        ClassLoader loader = Util.getCurrentLoader(null);
        if (loader == null) {
            return null;
        }

        return getMetaData(loader, className).lookupWriteMethod(propertyName);

    }


    /**
     * @param className the fully qualified class name
     * @param propertyName a JavaBeans property name
     * @return a method suitable for obtaining the value of a JavaBeans property,
     *  or null if the property doesn't exist or can't be read.
     */
    public static Method lookupReadMethod(String className, String propertyName) {


        ClassLoader loader = Util.getCurrentLoader(null);
        if (loader == null) {
            return null;
        }

        return getMetaData(loader, className).lookupReadMethod(propertyName);

    }


    // --------------------------------------------------------- Private Methods


    /**
     * Return the MetaData for the specified Class.
     * 
     * This will check the cache associated with the specified
     * ClassLoader.  If there is no cache hit, then a new
     * MetaData instance will be created and stored.
     * 
     * @param loader ClassLoader
     * @param clazz the Class of interest
     * @return a MetaData object for the specified Class
     */
    private static MetaData getMetaData(ClassLoader loader, Class clazz) {

        ConcurrentMap cache = REFLECTION_CACHE.get(loader);

        if (cache == null) {
            initCache(loader);
            cache = REFLECTION_CACHE.get(loader);
        }

        MetaData meta = cache.get(clazz.getName());
        if (meta == null) {
            meta = new MetaData(clazz);
            cache.put(clazz.getName(), meta);
        }
       
        return meta;

    }


    /**
     * 
Return the MetaData for the specified className.
     *
     * This will check the cache associated with the specified
     * ClassLoader.  If there is no cache hit, then a new
     * MetaData instance will be created and stored.
     *
     * @param loader ClassLoader
     * @param className the class of interest
     * @return a MetaData object for the specified Class
     */
    private static MetaData getMetaData(ClassLoader loader, String className) {

        ConcurrentMap cache = REFLECTION_CACHE.get(loader);

        if (cache == null) {
            initCache(loader);
            cache = REFLECTION_CACHE.get(loader);
        }

        MetaData meta = cache.get(className);
        if (meta == null) {
            try {
                Class clazz = Util.loadClass(className, cache);
                meta = new MetaData(clazz);
                cache.put(className, meta);
            } catch (ClassNotFoundException cnfe) {
                return null;
            }
        }

        return meta;
    }


    /**
     * 
MetaData contains lookup methods for Constructors and
     * Methods of a particular Class.
     */
    private static final class MetaData {


        Map constructors;
        Map> methods;
        Map> declaredMethods;
        Map propertyDescriptors;
        Class clazz;


    // ------------------------------------------------------------ Constructors


        /**
         * 
Constructs a new MetaData instance for the specified
         * class.
         * @param clazz class to construct a new MetaData instance from.
         */
        public MetaData(Class clazz) {

            String name;
            this.clazz = clazz;
            Constructor[] ctors = clazz.getConstructors();
            constructors = new HashMap<>(ctors.length, 1.0f);
            for (int i = 0, len = ctors.length; i < len; i++) {
                constructors.put(getKey(ctors[i].getParameterTypes()),
                                 ctors[i]);
            }
            Method[] meths = clazz.getMethods();
            methods = new HashMap<>(meths.length, 1.0f);
            for (int i = 0, len = meths.length; i < len; i++) {
                name = meths[i].getName();
                HashMap methodsMap = methods.get(name);
                if (methodsMap == null) {
                    methodsMap = new HashMap<>(4, 1.0f);
                    methods.put(name, methodsMap);
                }
                methodsMap.put(getKey(meths[i].getParameterTypes()), meths[i]);
            }
            
            meths = clazz.getDeclaredMethods();
            declaredMethods = new HashMap<>(meths.length, 1.0f);
            for (int i = 0, len = meths.length; i < len; i++) {
                name = meths[i].getName();
                HashMap declaredMethodsMap = declaredMethods.get(name);
                if (declaredMethodsMap == null) {
                    declaredMethodsMap = new HashMap<>(4, 1.0f);
                    declaredMethods.put(name, declaredMethodsMap);
                }
                declaredMethodsMap.put(getKey(meths[i].getParameterTypes()), meths[i]);
            }

            try {
                BeanInfo info = Introspector.getBeanInfo(clazz);
                PropertyDescriptor[] pds = info.getPropertyDescriptors();
                if (pds != null) {
                    if (propertyDescriptors == null) {
                        propertyDescriptors = new HashMap<>(pds.length, 1.0f);
                    }
                    for (PropertyDescriptor pd : pds) {
                        propertyDescriptors.put(pd.getName(), pd);
                    }
                }
            } catch (IntrospectionException ie) {
                if (LOGGER.isLoggable(Level.SEVERE)) {
                    LOGGER.log(Level.SEVERE,
                               ie.toString(),
                               ie);
                }
            }

        }


    // ---------------------------------------------------------- Public Methods


        /**
         * Looks up a Constructor based off the specified
         * params.
         * @param params constructor parameters
         * @return the Constructor appropriate to the specified 
         *  parameters or null
         */
        public Constructor lookupConstructor(Class... params) {

            return constructors.get(getKey(params));

        }


        /**
         * Looks up a Method based off the specified method
         * name and params.
         * @param name the name of the Method
         * @param params the Method parameters
         * @return the Method appropriate to the specified 
         *  name and parameters or null
         */
        public Method lookupMethod(String name, Class... params) {

            Map map = methods.get(name);
            Integer key = getKey(params);
            Method result = null;
            if ((null == map) || null == (result = map.get(key))) {
                map = declaredMethods.get(name);
                if (null != map) {
                    result = map.get(key);
                }
            }
            return result;

        }


        /**
         * Looks up the class for this MetaData instance.
         * @return the Class for this MetaData instance
         */
        public Class lookupClass() {

            return clazz;

        }


        /**
         * @param propName a JavaBeans property name
         * @return a method suitable for setting a JavaBeans property, or
         *  null if the property doesn't exist or is readonly.
         */
        public Method lookupWriteMethod(String propName) {

            if (propertyDescriptors == null) {
                return null;
            }

            PropertyDescriptor pd = propertyDescriptors.get(propName);
            if (pd != null) {
                return pd.getWriteMethod();
            }
            return null;

        }


        /**
         * @param propName a JavaBeans property name
         * @return a method suitable for obtaining the value of a JavaBeans property,
         *  or null if the property doesn't exist or can't be read.
         */
        public Method lookupReadMethod(String propName) {

            if (propertyDescriptors == null) {
                return null;
            }

            PropertyDescriptor pd = propertyDescriptors.get(propName);
            if (pd != null) {
                return pd.getReadMethod();
            }
            return null;

        }
        
    // --------------------------------------------------------- Private Methods


        /**
         * Return a hashcode of all the class parameters.
         * @param params the parameters to a Constructor or
         *  a Method instance
         * @return the result of Arrays.deepHashCode
         */
        private static Integer getKey(Class... params) {

            return Arrays.deepHashCode(params);

        }

    }

    
} // END ReflectionUtils