org.springframework.data.rest.webmvc.json.patch.JsonPatchPatchConverter.java Source code

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Here is the source code for org.springframework.data.rest.webmvc.json.patch.JsonPatchPatchConverter.java

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/*
 * Copyright 2014-2019 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
 *
 *      https://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.data.rest.webmvc.json.patch;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;

/**
 * Convert {@link JsonNode}s containing JSON Patch to/from {@link Patch} objects.
 *
 * @author Craig Walls
 * @author Oliver Gierke
 * @author Mathias Dsterhft
 * @author Oliver Trosien
 */
@RequiredArgsConstructor
public class JsonPatchPatchConverter implements PatchConverter<JsonNode> {

    private final @NonNull ObjectMapper mapper;

    /**
     * Constructs a {@link Patch} object given a JsonNode.
     *
     * @param jsonNode a JsonNode containing the JSON Patch
     * @return a {@link Patch}
     */
    public Patch convert(JsonNode jsonNode) {

        if (!(jsonNode instanceof ArrayNode)) {
            throw new IllegalArgumentException("JsonNode must be an instance of ArrayNode");
        }

        ArrayNode opNodes = (ArrayNode) jsonNode;
        List<PatchOperation> ops = new ArrayList<PatchOperation>(opNodes.size());

        for (Iterator<JsonNode> elements = opNodes.elements(); elements.hasNext();) {

            JsonNode opNode = elements.next();

            String opType = opNode.get("op").textValue();
            String path = opNode.get("path").textValue();

            JsonNode valueNode = opNode.get("value");
            Object value = valueFromJsonNode(path, valueNode);
            String from = opNode.has("from") ? opNode.get("from").textValue() : null;

            if (opType.equals("test")) {
                ops.add(TestOperation.whetherValueAt(path).hasValue(value));
            } else if (opType.equals("replace")) {
                ops.add(ReplaceOperation.valueAt(path).with(value));
            } else if (opType.equals("remove")) {
                ops.add(RemoveOperation.valueAt(path));
            } else if (opType.equals("add")) {
                ops.add(AddOperation.of(path, value));
            } else if (opType.equals("copy")) {
                ops.add(CopyOperation.from(from).to(path));
            } else if (opType.equals("move")) {
                ops.add(MoveOperation.from(from).to(path));
            } else {
                throw new PatchException("Unrecognized operation type: " + opType);
            }
        }

        return new Patch(ops);
    }

    private Object valueFromJsonNode(String path, JsonNode valueNode) {

        if (valueNode == null || valueNode.isNull()) {
            return null;
        } else if (valueNode.isTextual()) {
            return valueNode.asText();
        } else if (valueNode.isFloatingPointNumber()) {
            return valueNode.asDouble();
        } else if (valueNode.isBoolean()) {
            return valueNode.asBoolean();
        } else if (valueNode.isInt()) {
            return valueNode.asInt();
        } else if (valueNode.isLong()) {
            return valueNode.asLong();
        } else if (valueNode.isObject() || (valueNode.isArray())) {
            return new JsonLateObjectEvaluator(mapper, valueNode);
        }

        throw new PatchException(
                String.format("Unrecognized valueNode type at path %s and value node %s.", path, valueNode));
    }
}