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136 lines
4.0 KiB
JavaScript
136 lines
4.0 KiB
JavaScript
/*
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* Copyright DataStax, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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const util = require('util');
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const utils = require('../utils');
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const inspectMethod = util.inspect.custom || 'inspect';
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/**
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* Represents the result of an execution as an iterable of objects in the Mapper.
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* @alias module:mapping~Result
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*/
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class Result {
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/**
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* Creates a new instance of Result.
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* @param {ResultSet} rs
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* @param {ModelMappingInfo} info
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* @param {Function} rowAdapter
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*/
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constructor(rs, info, rowAdapter) {
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this._rs = rs;
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this._info = info;
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this._rowAdapter = rowAdapter;
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/**
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* When there is a single cell containing the result of the a LWT operation, hide the result from the user.
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* @private
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*/
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this._isEmptyLwt = (rs.columns !== null
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&& rs.columns.length === 1 && this._rs.rowLength === 1 && rs.columns[0].name === '[applied]');
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/**
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* Gets the amount of the documents contained in this Result instance.
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* <p>
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* When the results are paged, it returns the length of the current paged results not the total amount of
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* rows in the table matching the query.
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* </p>
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* @type {Number}
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*/
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this.length = this._isEmptyLwt ? 0 : (rs.rowLength || 0);
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/**
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* A string token representing the current page state of query.
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* <p>
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* When provided, it can be used in the following executions to continue paging and retrieve the remained of the
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* result for the query.
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* </p>
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* @type {String}
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* @default null
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*/
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this.pageState = rs.pageState;
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}
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/**
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* When this instance is the result of a conditional update query, it returns whether it was successful.
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* Otherwise, it returns <code>true</code>.
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* <p>
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* For consistency, this method always returns <code>true</code> for non-conditional queries (although there is
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* no reason to call the method in that case). This is also the case for conditional DDL statements
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* (CREATE KEYSPACE... IF NOT EXISTS, CREATE TABLE... IF NOT EXISTS), for which the server doesn't return
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* information whether it was applied or not.
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* </p>
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*/
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wasApplied() {
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return this._rs.wasApplied();
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}
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/**
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* Gets the first document in this result or null when the result is empty.
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*/
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first() {
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if (!this._rs.rowLength || this._isEmptyLwt) {
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return null;
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}
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return this._rowAdapter(this._rs.rows[0], this._info);
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}
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/**
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* Returns a new Iterator object that contains the document values.
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*/
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*[Symbol.iterator]() {
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if (this._isEmptyLwt) {
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// Empty iterator
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return;
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}
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for (let i = 0; i < this._rs.rows.length; i++) {
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yield this._rowAdapter(this._rs.rows[i], this._info);
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}
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}
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/**
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* Converts the current instance to an Array of documents.
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* @return {Array<Object>}
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*/
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toArray() {
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if (this._isEmptyLwt || !this._rs.rows) {
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return utils.emptyArray;
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}
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return this._rs.rows.map(row => this._rowAdapter(row, this._info));
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}
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/**
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* Executes a provided function once per result element.
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* @param {Function} callback Function to execute for each element, taking two arguments: currentValue and index.
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* @param {Object} [thisArg] Value to use as <code>this</code> when executing callback.
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*/
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forEach(callback, thisArg) {
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let index = 0;
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thisArg = thisArg || this;
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for (const doc of this) {
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callback.call(thisArg, doc, index++);
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}
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}
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[inspectMethod]() {
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return this.toArray();
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}
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}
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module.exports = Result; |