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package com.epam.commons;
/*
 * Copyright 2004-2016 EPAM Systems
 *
 * This file is part of JDI project.
 *
 * JDI 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.
 *
 * JDI 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 JDI. If not, see .
 */

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Function;

import static com.epam.commons.LinqUtils.any;
import static java.lang.String.format;
import static java.lang.reflect.Modifier.isStatic;
import static java.util.Arrays.asList;

/**
 * Created by roman.i on 25.09.2014.
 */
public final class ReflectionUtils {
    private ReflectionUtils() { }
    public static boolean isClass(Field field, Class expected) {
        return isClass(field.getType(), expected);
    }

    public static boolean isClass(Class t, Class expected) {
        if (expected == Object.class)
            return true;
        Class type = t;
        while (type != null && type != Object.class)
            if (type == expected) return true;
            else type = type.getSuperclass();
        return false;
    }

    public static boolean isClass(Class type, Class... expected) {
        for (Class expectedType : expected) {
            Class actualType = type;
            if (expectedType == Object.class) return true;
            while (actualType != null && actualType != Object.class)
                if (actualType == expectedType) return true;
                else actualType = actualType.getSuperclass();
        }
        return false;
    }

    public static boolean isInterface(Field field, Class expected) {
        return isInterface(field.getType(), expected);
    }

    public static boolean isInterface(Class type, Class expected) {
        if (type == null || expected == null || type == Object.class)
            return false;
        if (type == expected)
            return true;
        List interfaces = asList(type.getInterfaces());
        return any(interfaces, i -> isInterface(i, expected)) || isInterface(type.getSuperclass(), expected);
    }

    public static List getFields(Object obj, Class... types) {
        return getFields(obj, types, Object.class);
    }
    public static List getFields(Object obj, Class[] types, Class... stopTypes) {
        return getFields(getFieldsDeep(obj.getClass(), stopTypes), types, f -> !isStatic(f.getModifiers()));
    }
    public static List getFields(List fields, Class[] types, Function filter) {
        return LinqUtils.where(fields,
                field -> filter.apply(field) && isExpectedClass(field, types));
    }

    private static List getFieldsDeep(Class type, Class... types) {
        if (asList(types).contains(type))
            return new ArrayList<>();
        List result = new ArrayList<>(asList(type.getDeclaredFields()));
        result.addAll(getFieldsDeep(type.getSuperclass(), types));
        return result;
    }

    public static  T getFirstField(Object obj, Class... types) {
        return (T) getValueField(LinqUtils.first(obj.getClass().getDeclaredFields(), field -> isExpectedClass(field, types)), obj);
    }
    private static boolean isExpectedClass(Field field, Class... types) {
        for (Class type : types)
            if (isClass(field, type) || isInterface(field, type))
                return true;
        return false;
    }

    public static Object getValueField(Field field, Object obj) {
        field.setAccessible(true);
        try {
            return field.get(obj);
        } catch (Exception ex) {
            throw new RuntimeException(format("Can't get field '%s' value", field.getName()));
        }
    }

    public static Object convertStringToType(String value, Field field)
    {
        Class clazz = field.getType();
        if (clazz.isAssignableFrom(String.class)|| value == null)
            return value;
        if (clazz.isAssignableFrom(Byte.class))
            return Byte.parseByte(value);
        if (clazz.isAssignableFrom(Short.class))
            return Short.parseShort(value);
        if (clazz.isAssignableFrom(Integer.class))
            return Integer.parseInt(value);
        if (clazz.isAssignableFrom(Long.class))
            return Long.parseLong(value);
        if (clazz.isAssignableFrom(Float.class))
            return Float.parseFloat(value);
        if (clazz.isAssignableFrom(Double.class))
            return Float.parseFloat(value);
        if (clazz.isAssignableFrom(Boolean.class))
            return Boolean.parseBoolean(value);

        throw new IllegalArgumentException("Can't parse field " + field.getName() + ". Type [" + clazz + "] is unsupported");
    }

    public static  Class checkEntityIsNotNull(Class entityClass) {
        if (entityClass == null)
            throw new IllegalArgumentException("Entity type was not specified");
        return entityClass;
    }

    public static  T newEntity(Class entityClass) {
        try {
            return entityClass.newInstance();
        } catch (InstantiationException | IllegalAccessException e) {
            throw new RuntimeException("Can't instantiate " + entityClass.getSimpleName() +
                    ". You must have empty constructor to do this");
        }
    }
}




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