jp.furplag.util.JSONifier.java Source code

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Here is the source code for jp.furplag.util.JSONifier.java

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/**
 * Copyright (C) 2015+ furplag (https://github.com/furplag/)
 *
 * 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 jp.furplag.util;

import java.io.IOException;

import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import jp.furplag.util.commons.ObjectUtils;

/**
 * utilities for convert between Object and JSON.
 *
 * @author furplag
 */
public final class JSONifier {

    /**
     * JSONifier instances should NOT be constructed in standard programming.
     */
    private JSONifier() {
    }

    /** ignore unknown field mapping error. */
    private static final ObjectMapper MAPPER = new ObjectMapper()
            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

    /**
     * create the instance of specified class represented by the JSON String. Throw exceptions if convert has failed.
     *
     * @param str JSON String.
     * @param type destination Class.
     * @return the instance of specified Class.
     * @throws JsonParseException
     * @throws JsonMappingException
     * @throws IOException
     */
    public static <T> T parse(final String str, final Class<T> type)
            throws JsonParseException, JsonMappingException, IOException {
        if (str == null)
            return type == null ? null : type.isPrimitive() ? MAPPER.readValue("", type) : null;

        return MAPPER.readValue(str, type);
    }

    /**
     * create the instance of specified class represented by the JSON String. Throw exceptions if convert has failed.
     *
     * @param str JSON String.
     * @param typeRef {@link com.fasterxml.jackson.core.type.TypeReference}.
     * @return the instance of specified Class.
     * @throws JsonParseException
     * @throws JsonMappingException
     * @throws IOException
     */
    public static <T> T parse(final String str, final TypeReference<T> typeRef)
            throws JsonParseException, JsonMappingException, IOException {
        if (str != null && typeRef != null)
            return MAPPER.readValue(str, typeRef);

        return null;
    }

    /**
     * create the instance of specified class represented by the JSON String. Return empty instance if convert has failed.
     *
     * @param str JSON String.
     * @param type destination Class.
     * @return the instance of specified Class.
     */
    public static <T> T parseLazy(final String str, final Class<T> type) {
        try {
            return parse(str, type);
        } catch (Exception e) {
            try {
                return ObjectUtils.newInstance(type);
            } catch (Exception ex) {
            }
        }

        return null;
    }

    /**
     * create the instance of specified class represented by the JSON String. Return empty instance if convert has failed.
     *
     * @param str JSON String.
     * @param typeRef {@link com.fasterxml.jackson.core.type.TypeReference}.
     * @return the instance of specified class.
     */
    public static <T> T parseLazy(final String str, final TypeReference<T> typeRef) {
        try {
            return parse(str, typeRef);
        } catch (Exception e) {
            try {
                return ObjectUtils.newInstance(typeRef);
            } catch (Exception ex) {
            }
        }

        return null;
    }

    /**
     * stringify specified object. Throw exceptions if stringify has failed.
     *
     * @param o an Object, may be null.
     * @return JSON String.
     * @throws JsonGenerationException
     * @throws JsonMappingException
     * @throws IOException
     */
    public static String stringify(final Object o)
            throws JsonGenerationException, JsonMappingException, IOException {
        return MAPPER.writeValueAsString(o);
    }

    /**
     * stringify specified object. Return empty String if stringify has failed.
     *
     * @param obj an Object, may be null.
     * @return JSON String.
     */
    public static String stringifyLazy(final Object o) {
        try {
            return stringify(o);
        } catch (Exception e) {
        }

        return "null";
    }
}