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JSON Patch (RFC 6902) and JSON Merge Patch (RFC 7386) implementation in Java

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/*
 * Copyright (c) 2013, Francis Galiegue 
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Lesser GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */

package com.github.fge.jsonpatch;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.JsonNode;
import com.github.fge.jackson.jsonpointer.JsonPointer;

/**
 * JSON Patch {@code move} operation
 *
 * For this operation, {@code from} points to the value to move, and {@code
 * path} points to the new location of the moved value.
 *
 * As for {@code add}:
 *
 * 
 *     the value at the destination path is either created or replaced;
 *     it is created only if the immediate parent exists;
 *     {@code -} appends at the end of an array.
 * 
 *
 * It is an error condition if {@code from} does not point to a JSON value.
 * 
 *
 * The specification adds another rule that the {@code from} path must not be
 * an immediate parent of {@code path}. Unfortunately, that doesn't really work.
 * Consider this patch:
 *
 *  *     { "op": "move", "from": "/0", "path": "/0/x" }
 * 
 *
 * Even though {@code /0} is an immediate parent of {@code /0/x}, when this
 * patch is applied to:
 *
 *  *     [ "victim", {} ]
 * 
 *
 * it actually succeeds and results in the patched value:
 *
 *  *     [ { "x": "victim" } ]
 * 
 */
public final class MoveOperation
    extends DualPathOperation
{
    @JsonCreator
    public MoveOperation(@JsonProperty("from") final JsonPointer from,
        @JsonProperty("path") final JsonPointer path)
    {
        super(from, path);
    }

    @Override
    public JsonNode apply(final JsonNode node)
        throws JsonPatchException
    {
        if (from.equals(path))
            return node.deepCopy();
        final JsonNode movedNode = from.path(node);
        if (movedNode.isMissingNode())
            throw new JsonPatchException(JsonPatchMessages.NO_SUCH_PATH);
        final JsonPatchOperation remove = new RemoveOperation(from);
        final JsonPatchOperation add = new AddOperation(path, movedNode);
        return add.apply(remove.apply(node));
    }

    @Override
    public String toString()
    {
        return "move: " + super.toString();
    }
}