org.springframework.tuple.TupleToJsonStringConverter.java Source code

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Here is the source code for org.springframework.tuple.TupleToJsonStringConverter.java

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/*
 * Copyright 2002-2015 the original author or authors.
 *
 * 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.springframework.tuple;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.BaseJsonNode;
import org.springframework.core.convert.converter.Converter;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

import java.util.List;

/**
 * Converts a Tuple to JSON representation
 *
 * @author David Turanski
 * @author Gunnar Hillert
 */
public class TupleToJsonStringConverter implements Converter<Tuple, String> {

    private final ObjectMapper mapper = new ObjectMapper();

    @Override
    public String convert(Tuple source) {
        ObjectNode root = toObjectNode(source);
        String json = null;
        try {
            json = mapper.writeValueAsString(root);
        } catch (Exception e) {
            throw new IllegalArgumentException("Tuple to string conversion failed", e);
        }
        return json;
    }

    private ObjectNode toObjectNode(Tuple source) {
        ObjectNode root = mapper.createObjectNode();
        for (int i = 0; i < source.size(); i++) {
            Object value = source.getValues().get(i);
            String name = source.getFieldNames().get(i);
            if (value == null) {
                root.putNull(name);
            } else {
                root.putPOJO(name, toNode(value));
            }
        }
        return root;
    }

    private ArrayNode toArrayNode(List<?> source) {
        ArrayNode array = mapper.createArrayNode();
        for (Object value : source) {
            if (value != null) {
                array.add(toNode(value));
            }
        }
        return array;
    }

    private BaseJsonNode toNode(Object value) {
        if (value != null) {
            if (value instanceof Tuple) {
                return toObjectNode((Tuple) value);
            } else if (value instanceof List<?>) {
                return toArrayNode((List<?>) value);
            } else if (!value.getClass().isPrimitive()) {
                return mapper.getNodeFactory().pojoNode(value);
            } else {
                return mapper.valueToTree(value);
            }
        }
        return null;
    }

}