| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| /** |
| * @author Jorge Bay Gondra |
| */ |
| 'use strict'; |
| |
| const t = require('../process/traversal'); |
| const TraversalStrategy = require('../process/traversal-strategy').TraversalStrategy; |
| |
| /** |
| * Represents an abstraction of a "connection" to a "server" that is capable of processing a traversal and |
| * returning results. |
| */ |
| class RemoteConnection { |
| /** |
| * @param {String} url The resource uri. |
| * @param {Object} [options] The connection options. |
| */ |
| constructor(url, options = {}) { |
| this.url = url; |
| this.options = options; |
| } |
| |
| /** |
| * Opens the connection, if its not already opened. |
| * @returns {Promise} |
| */ |
| open() { |
| throw new Error('open() must be implemented'); |
| } |
| |
| /** |
| * Returns true if connection is open |
| * @returns {Boolean} |
| */ |
| get isOpen() { |
| throw new Error('isOpen() must be implemented'); |
| } |
| |
| /** |
| * Determines if the connection is already bound to a session. If so, this indicates that the |
| * <code>#createSession()</code> cannot be called so as to produce child sessions. |
| * @returns {boolean} |
| */ |
| get isSessionBound() { |
| return false; |
| } |
| |
| /** |
| * Submits the <code>Bytecode</code> provided and returns a <code>RemoteTraversal</code>. |
| * @abstract |
| * @param {Bytecode} bytecode |
| * @returns {Promise} Returns a <code>Promise</code> that resolves to a <code>RemoteTraversal</code>. |
| */ |
| submit(bytecode) { |
| throw new Error('submit() must be implemented'); |
| } |
| |
| /** |
| * Create a new <code>RemoteConnection</code> that is bound to a session using the configuration from this one. |
| * If the connection is already session bound then this function should throw an exception. |
| * @returns {RemoteConnection} |
| */ |
| createSession() { |
| throw new Error('createSession() must be implemented'); |
| } |
| |
| /** |
| * Submits a <code>Bytecode.GraphOp.commit</code> to the server and closes the connection. |
| * @returns {Promise} |
| */ |
| commit() { |
| throw new Error('commit() must be implemented'); |
| } |
| /** |
| * Submits a <code>Bytecode.GraphOp.rollback</code> to the server and closes the connection. |
| * @returns {Promise} |
| */ |
| rollback() { |
| throw new Error('rollback() must be implemented'); |
| } |
| |
| /** |
| * Closes the connection where open transactions will close according to the features of the graph provider. |
| * @returns {Promise} |
| */ |
| close() { |
| throw new Error('close() must be implemented'); |
| } |
| } |
| |
| /** |
| * Represents a traversal as a result of a {@link RemoteConnection} submission. |
| */ |
| class RemoteTraversal extends t.Traversal { |
| constructor(traversers, sideEffects) { |
| super(null, null, null); |
| this.traversers = traversers; |
| this.sideEffects = sideEffects; |
| } |
| } |
| |
| class RemoteStrategy extends TraversalStrategy { |
| /** |
| * Creates a new instance of RemoteStrategy. |
| * @param {RemoteConnection} connection |
| */ |
| constructor(connection) { |
| // gave this a fqcn that has a local "js:" prefix since this strategy isn't sent as bytecode to the server. |
| // this is a sort of local-only strategy that actually executes client side. not sure if this prefix is the |
| // right way to name this or not, but it should have a name to identify it. |
| super('js:RemoteStrategy'); |
| this.connection = connection; |
| } |
| |
| /** @override */ |
| apply(traversal) { |
| if (traversal.traversers) { |
| return Promise.resolve(); |
| } |
| |
| return this.connection.submit(traversal.getBytecode()).then(function (remoteTraversal) { |
| traversal.sideEffects = remoteTraversal.sideEffects; |
| traversal.traversers = remoteTraversal.traversers; |
| }); |
| } |
| } |
| |
| module.exports = { RemoteConnection, RemoteStrategy, RemoteTraversal }; |