webbeta / Serializer

import com.google.common.collect.Lists;

import es.webbeta.serializer.base.Logger;

import es.webbeta.serializer.type.FieldAccessType;

import java.lang.reflect.Field;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.List;

    private Boolean initialized = false;

    private Class<?> klass;

    private List<Class<?>> klassTree;

    private Object ob;

    private String fieldName;

    private FieldAccessType accessType;

    private Logger logger;

    private Boolean exists = false;

    private Object value = null;

    private Boolean ensureFieldExists = true;

    private String customGetterName;

    public FieldAccessor(

            Object ob,

            String fieldName,

            FieldAccessType accessType

    ) {

        this.ob = ob;

        this.fieldName = fieldName;

        this.accessType = accessType;

        klass = ob.getClass();

        klassTree = new ArrayList<>();

        klassTree.add(klass);

    }

    public void setLogger(Logger logger) {

        this.logger = logger;

    }

    private String[] buildGetterNames(String fieldName) {

        List<String> names = new ArrayList<>();

        String firstLetter = fieldName.substring(0, 1);

        names.add("get" + firstLetter.toUpperCase() + fieldName.substring(1));

        names.add("is" + firstLetter.toUpperCase() + fieldName.substring(1));

        return names.toArray(new String[0]);

    }

    private void init() {

        if (initialized) return;

        Class<?> superKlass = klass;

        while (superKlass != null) {

            superKlass = superKlass.getSuperclass();

            if (superKlass.getCanonicalName().equals(Object.class.getCanonicalName()))

                break;

            klassTree.add(superKlass);

        }

        klassTree = Lists.reverse(klassTree);

        if (accessType == FieldAccessType.PROPERTY)

            buildAsProperty();

        else if (accessType == FieldAccessType.PUBLIC_METHOD)

            buildAsMethod();

        initialized = true;

    }

    }

    private void buildAsMethod() {

        if (!Modifier.isPublic(klass.getModifiers()))

            throw new IllegalAccessError("Serializer cannot access \"" + klass.getCanonicalName() + "\" class. It can be caused because it has non public access.");

        String[] names;

        if (customGetterName == null)

            names = buildGetterNames(fieldName);

        else

            names = new String[]{customGetterName};

        for (String name : names) {

            try {

                Method method = klass.getMethod(name);

                value = method.invoke(ob);

                exists = true;

                break;

            } catch (NoSuchMethodException ignored) {

                exists = false;

            } catch (IllegalAccessException | InvocationTargetException e) {

                if (logger != null) {

                    logger.error(String.format("Serializer cannot serialize method '%s.%s', because it %s",

                            klass.getCanonicalName(), name,

                                    "throw an exception when was called."

                    ));

                }

            }

        }

        if (ensureFieldExists) {

            FieldAccessor accessorAsField =

                    new FieldAccessor(ob, fieldName, FieldAccessType.PROPERTY);

            exists = exists && accessorAsField.exists();

            if (!exists)

                value = null;

        }

    }

    public void setEnsureFieldExists(Boolean ensureFieldExists) {

        this.ensureFieldExists = ensureFieldExists;

    }

    public void setCustomGetterName(String customGetterName) {

        this.customGetterName = customGetterName;

    }

    @Override

    public Boolean exists() {

        init();

        return exists;

    }

    @SuppressWarnings("unchecked")

    @Override

    public <T> T get() {

        init();

        return (T) value;

    }

}