kvclient-js
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Oracle NoSQL Database node.js Client API.
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<h1 class="page-title">Source: Iterator.js</h1>
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<pre class="prettyprint source linenums"><code>/*-
*
* This file is part of Oracle NoSQL Database
* Copyright (C) 2011, 2014 Oracle and/or its affiliates. All rights reserved.
*
* If you have received this file as part of Oracle NoSQL Database the
* following applies to the work as a whole:
*
* Oracle NoSQL Database server software is free software: you can
* redistribute it and/or modify it under the terms of the GNU Affero
* General Public License as published by the Free Software Foundation,
* version 3.
*
* Oracle NoSQL Database 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 GNU
* Affero General Public License for more details.
*
* If you have received this file as part of Oracle NoSQL Database Client or
* distributed separately the following applies:
*
* Oracle NoSQL Database client software is free software: you can
* redistribute it and/or modify it under the terms of the Apache License
* as published by the Apache Software Foundation, version 2.0.
*
* You should have received a copy of the GNU Affero General Public License
* and/or the Apache License in the LICENSE file along with Oracle NoSQL
* Database client or server distribution. If not, see
* <http://www.gnu.org/licenses/>
* or
* <http://www.apache.org/licenses/LICENSE-2.0>.
*
* An active Oracle commercial licensing agreement for this product supersedes
* these licenses and in such case the license notices, but not the copyright
* notice, may be removed by you in connection with your distribution that is
* in accordance with the commercial licensing terms.
*
* For more information please contact:
*
* berkeleydb-info_us@oracle.com
*
*/
"use strict";
/*global kvLogger*/
/*global LOG_LEVELS*/
/*global Errors*/
/*global Types*/
var EventEmitter = require('events').EventEmitter;
util.inherits(Iterator, EventEmitter);
/**
* Creates an iterator based on
* @param kvClient
* @param iteratorResult
* @constructor
*/
function Iterator(/*kvClient*/ kvClient, /*TIteratorResult*/ iteratorResult) {
EventEmitter.call(this);
var self = this;
var iteratorId = iteratorResult.iteratorId;
var closed = false;
var buffer = iteratorResult.result.rowsWithMetadata;
var hasMore = iteratorResult.hasMore;
var index, length;
var buffering = false;
resetIndexes();
function resetIndexes() {
index = 0;
length = buffer.length - 1;
}
function parseRow(row) {
if (row)
if (row.jsonRow) {
row.row = JSON.parse(row.jsonRow);
delete row.jsonRow;
}
return row;
}
//function available() {
// return (length>=index || hasMore) && !buffering;
//}
//this.available = available;
function isClosed() {
return closed;
}
this.isClosed = isClosed;
function next(callback) {
callback = callback || function(){};
if (closed) {
callback(new Error(Errors.ITERATOR_CLOSED));
}
if (length>=index) { //available from buffer
parseRow(buffer[index]);
callback(null, buffer[index++]);
return;
}
if (hasMore) {
buffering = true;
kvClient.iteratorNext(iteratorId, function (err, result) {
if (result != null) {
buffer = result.result.rowsWithMetadata;
resetIndexes();
parseRow(buffer[index]);
callback(null, buffer[index]);
index++;
}
});
}
callback(new Error(Errors.NO_MORE_ELEMENTS));
self.emit("finish");
}
this.next = next;
function getCurrent(callback) {
kvLogger.debug("Iterator - getCurrent");
var _index = index-1;
if (closed) {
callback(new Error(Errors.ITERATOR_CLOSED));
return;
}
parseRow(buffer[_index]);
if (length>=_index)
callback(null, buffer[_index]);
};
this.getCurrent = getCurrent;
function forEach(callback) {
kvLogger.debug("Iterator - forEach");
if (closed) {
callback(new Error(Errors.ITERATOR_CLOSED));
return;
}
var lastEntry = false;
while(true) { //depleting buffer
if (length>=index) {
parseRow(buffer[index]);
callback(null, buffer[index++]);
} else if (hasMore) {
kvClient.iteratorNext(iteratorId, function (err, result) {
if (result != null) {
buffer = result.result.rowsWithMetadata;
hasMore = result.hasMore;
resetIndexes();
forEach(callback);
}
});
break;
} else {
lastEntry = true;
break;
}
}
if (lastEntry) // means this is the last entry, no more items available
self.emit("finish");
}
this.forEach = forEach;
function close(callback) {
kvLogger.debug("Iterator - close");
if (closed) {
callback(new Error(Errors.ITERATOR_CLOSED));
return;
}
kvClient.iteratorClose(iteratorId, callback);
}
this.close = close;
}
module.exports = Iterator;
</code></pre>
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