Android Open Source - spring-sync Json Patch Patch Converter

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The source code is released under:
Apache License
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Java Source Code

/*
 * Copyright 2014 the original author or authors.
 *//from   ww  w  .  j  ava  2s.  c om
 * 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.sync.json;

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

import org.springframework.sync.AddOperation;
import org.springframework.sync.CopyOperation;
import org.springframework.sync.FromOperation;
import org.springframework.sync.MoveOperation;
import org.springframework.sync.Patch;
import org.springframework.sync.PatchException;
import org.springframework.sync.PatchOperation;
import org.springframework.sync.RemoveOperation;
import org.springframework.sync.ReplaceOperation;
import org.springframework.sync.TestOperation;

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

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

  private static final ObjectMapper MAPPER = new ObjectMapper();

  /**
   * 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(new TestOperation(path, value));
      } else if (opType.equals("replace")) {
        ops.add(new ReplaceOperation(path, value));
      } else if (opType.equals("remove")) {
        ops.add(new RemoveOperation(path));
      } else if (opType.equals("add")) {
        ops.add(new AddOperation(path, value));
      } else if (opType.equals("copy")) {
        ops.add(new CopyOperation(path, from));
      } else if (opType.equals("move")) {
        ops.add(new MoveOperation(path, from));
      } else {
        throw new PatchException("Unrecognized operation type: " + opType);
      }
    }
    
    return new Patch(ops);
  }
  
  /**
   * Renders a {@link Patch} as a {@link JsonNode}.
   * @param patch the patch
   * @return a {@link JsonNode} containing JSON Patch.
   */
  public JsonNode convert(Patch patch) {
    
    List<PatchOperation> operations = patch.getOperations();
    JsonNodeFactory nodeFactory = JsonNodeFactory.instance;
    ArrayNode patchNode = nodeFactory.arrayNode();
    for (PatchOperation operation : operations) {
      ObjectNode opNode = nodeFactory.objectNode();
      opNode.set("op", nodeFactory.textNode(operation.getOp()));
      opNode.set("path", nodeFactory.textNode(operation.getPath()));
      if (operation instanceof FromOperation) {
        FromOperation fromOp = (FromOperation) operation;
        opNode.set("from", nodeFactory.textNode(fromOp.getFrom()));
      }
      Object value = operation.getValue();
      if (value != null) {
        opNode.set("value", MAPPER.valueToTree(value));
      }
      patchNode.add(opNode);
    }
    
    return patchNode;
  }

  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()) {
      return new JsonLateObjectEvaluator(valueNode);
    } else if (valueNode.isArray()) {
      // TODO: Convert valueNode to array
    }
    
    return null;
  }
  
  

  
}
Java Source Code List
