openmct/platform/entanglement/src/services/LinkService.js

/*****************************************************************************
 * Open MCT Web, Copyright (c) 2014-2015, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT Web is 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
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 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT Web includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
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 *****************************************************************************/

/*global define */

define(
    function () {
        "use strict";

        /**
         * LinkService provides an interface for linking objects to additional
         * locations.  It also provides a method for determining if an object
         * can be copied to a specific location.
         * @constructor
         * @memberof platform/entanglement
         * @implements {platform/entanglement.AbstractComposeService}
         */
        function LinkService(policyService) {
            this.policyService = policyService;
        }

        LinkService.prototype.validate = function (object, parentCandidate) {
            if (!parentCandidate || !parentCandidate.getId) {
                return false;
            }
            if (parentCandidate.getId() === object.getId()) {
                return false;
            }
            if (parentCandidate.getModel().composition.indexOf(object.getId()) !== -1) {
                return false;
            }
            return this.policyService.allow(
                "composition",
                parentCandidate.getCapability('type'),
                object.getCapability('type')
            );
        };

        LinkService.prototype.perform = function (object, parentObject) {
            function findChild(children) {
                var i;
                for (i = 0; i < children.length; i += 1) {
                    if (children[i].getId() === object.getId()) {
                        return children[i];
                    }
                }
            }

            return parentObject.useCapability('mutation', function (model) {
                if (model.composition.indexOf(object.getId()) === -1) {
                    model.composition.push(object.getId());
                }
            }).then(function () {
                return parentObject.getCapability('persistence').persist();
            }).then(function getObjectWithNewContext() {
                return parentObject
                    .useCapability('composition')
                    .then(findChild);
            });
        };

        return LinkService;
    }
);