org.brunocvcunha.digesteroids.cast.DigesteroidsDefaultCaster.java Source code

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Here is the source code for org.brunocvcunha.digesteroids.cast.DigesteroidsDefaultCaster.java

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/**
 * Copyright (C) 2015 Bruno Candido Volpato da Cunha (brunocvcunha@gmail.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.brunocvcunha.digesteroids.cast;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;

/**
 * Reflection Difference Handling
 * 
 * @author Bruno Candido Volpato da Cunha
 */
public class DigesteroidsDefaultCaster implements DigesteroidsCaster {

    private static Logger log = Logger.getLogger(DigesteroidsDefaultCaster.class);

    /**
     * Constant for Map of String to Object
     */
    public static final Type _obj_map_token = new TypeToken<HashMap<String, Object>>() {
        //no impl
    }.getType();

    /**
     * Constant for List of Map from String to Object
     */
    public static final Type _obj_map_list_token = new TypeToken<ArrayList<HashMap<String, Object>>>() {
        //no impl
    }.getType();

    /**
     * The default format for date and time
     */
    public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";

    /**
     * The default format for date
     */
    public static final String DEFAULT_DATE_ONLY_FORMAT = "yyyy-MM-dd";

    /**
     * The default date/time formatter
     */
    public static final DateTimeFormatter DATE_FORMAT_PARSER = DateTimeFormat.forPattern(DEFAULT_DATE_FORMAT)
            .withZoneUTC();

    private static DigesteroidsDefaultCaster instance;

    private DigesteroidsDefaultCaster() {
    }

    /**
     * @return singleton instance
     */
    public static DigesteroidsDefaultCaster getInstance() {
        if (instance == null) {
            instance = new DigesteroidsDefaultCaster();
        }

        return instance;
    }

    private static Gson gson = new GsonBuilder().create();
    private static Gson gsonPretty = new GsonBuilder().setPrettyPrinting().create();

    @Override
    public String json(Object value) {
        if (value == null) {
            return null;
        }

        return gson.toJson(value);
    }

    @Override
    public String jsonPretty(Object value) {
        if (value == null) {
            return null;
        }

        return gsonPretty.toJson(value);
    }

    @Override
    public String string(Object value) {
        if (value == null) {
            return null;
        }

        if (value instanceof String) {
            return (String) value;
        }

        return String.valueOf(value);
    }

    @Override
    public Map<String, Object> map(Object value) {
        if (value instanceof Map) {
            return (Map<String, Object>) value;
        }

        String json;
        if (value instanceof String) {
            json = (String) value;
        } else {
            json = gson.toJson(value);
        }

        return gson.fromJson(json, _obj_map_token);
    }

    @Override
    public List<Map<String, Object>> mapList(Object value) {
        String json;
        if (value instanceof String) {
            json = (String) value;
        } else {
            json = gson.toJson(value);
        }

        return gson.fromJson(json, _obj_map_list_token);
    }

    @Override
    public Date date(Object value) {
        if (value instanceof GregorianCalendar) {
            return ((GregorianCalendar) value).getTime();
        }

        return DATE_FORMAT_PARSER.parseDateTime(String.valueOf(value)).toDate();
    }

    @Override
    public <T> T cast(Object value, Type targetType) {
        return cast(value, targetType, null);
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T cast(Object value, Type targetType, String source) {

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

        TypeToken<T> typeToken = (TypeToken<T>) TypeToken.get(targetType);
        Class<T> toClazz = (Class<T>) typeToken.getRawType();

        log.debug("Handling value conversion (" + value.getClass() + " / " + value.toString() + ") to " + toClazz);

        if (toClazz.isAssignableFrom(String.class)) {
            return (T) string(value);
        }

        if (toClazz.isAssignableFrom(Byte.class)) {
            return (T) Byte.valueOf(value.toString());
        }

        if (toClazz.isAssignableFrom(Short.class)) {
            return (T) Short.valueOf(value.toString());
        }

        if (toClazz.isAssignableFrom(Integer.class)) {
            return (T) Integer.valueOf(Double.valueOf(value.toString()).intValue());
        }

        if (toClazz.isAssignableFrom(Long.class)) {
            return (T) Long.valueOf(Double.valueOf(value.toString()).longValue());
        }

        if (toClazz.isAssignableFrom(Double.class)) {
            return (T) Double.valueOf(value.toString());
        }

        if (toClazz.isAssignableFrom(Date.class)) {
            return (T) date(value);
        }

        //    throw new IllegalArgumentException("Need to convert value (" + value.getClass() + " / " + value.toString() + ") to " + toClazz);

        if (value instanceof String) {
            try {
                return gson.fromJson((String) value, targetType);
            } catch (Exception e) {
                //it's ok
                log.debug("Exception trying to convert string to type", e);
            }
        }

        return gson.fromJson(gson.toJson(value), targetType);
    }

    @Override
    public Element htmlElement(Object value) {
        if (value instanceof Element) {
            return (Element) value;
        }

        Document document = Jsoup.parse(string(value));
        return document;
    }

}