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arangodb/js/client/modules/@arangodb/arango-query-cursor.js

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JavaScript

/*jshint strict: false */
/*global more:true */
////////////////////////////////////////////////////////////////////////////////
/// @brief ArangoQueryCursor
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2013 triagens GmbH, Cologne, Germany
///
/// 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
/// 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.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Achim Brandt
/// @author Dr. Frank Celler
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
var internal = require("internal");
var arangosh = require("@arangodb/arangosh");
////////////////////////////////////////////////////////////////////////////////
/// @brief constructor
////////////////////////////////////////////////////////////////////////////////
function ArangoQueryCursor (database, data) {
this._database = database;
this._dbName = database._name();
this.data = data;
this._hasNext = false;
this._hasMore = false;
this._pos = 0;
this._count = 0;
this._total = 0;
if (data.result !== undefined) {
this._count = data.result.length;
if (this._pos < this._count) {
this._hasNext = true;
}
if (data.hasMore !== undefined && data.hasMore) {
this._hasMore = true;
}
}
}
exports.ArangoQueryCursor = ArangoQueryCursor;
////////////////////////////////////////////////////////////////////////////////
/// @brief return a string representation of the cursor
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.toString = function () {
var isCaptureModeActive = internal.isCaptureMode();
var rows = [ ], i = 0;
while (++i <= 10 && this.hasNext()) {
rows.push(this.next());
}
var result = "[object ArangoQueryCursor";
if (this.data.id) {
result += " " + this.data.id;
}
if (this._count !== null && this._count !== undefined) {
result += ", count: " + this._count;
}
result += ", hasMore: " + (this.hasNext() ? "true" : "false");
if (this.data.hasOwnProperty("extra") &&
this.data.extra.hasOwnProperty("warnings")) {
for (var j = 0; j < this.data.extra.warnings.length; j++) {
result += ", warning: " + this.data.extra.warnings[j].code +
" - " + this.data.extra.warnings[j].message;
}
}
result += "]";
if (!isCaptureModeActive) {
internal.print(result);
result = "";
}
if (rows.length > 0) {
if (!isCaptureModeActive) {
var old = internal.startCaptureMode();
internal.print(rows);
result += "\n\n" + internal.stopCaptureMode(old);
}
else {
internal.print(rows);
}
if (this.hasNext()) {
result += "\ntype 'more' to show more documents\n";
more = this; // assign cursor to global variable more!
}
}
if (!isCaptureModeActive) {
internal.print(result);
result = "";
}
return result;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return all remaining result documents from the cursor
///
/// If no more results are available locally but more results are available on
/// the server, this function will make one or multiple roundtrips to the
/// server. Calling this function will also fully exhaust the cursor.
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.toArray = function () {
var result = [];
while (this.hasNext()) {
result.push(this.next());
}
return result;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief print the help for the cursor
////////////////////////////////////////////////////////////////////////////////
var helpArangoQueryCursor = arangosh.createHelpHeadline("ArangoQueryCursor help") +
'ArangoQueryCursor constructor: ' + "\n" +
' > cursor = stmt.execute() ' + "\n" +
'Functions: ' + "\n" +
' hasNext() returns true if there are ' + "\n" +
' more results to fetch ' + "\n" +
' next() returns the next document ' + "\n" +
' toArray() returns all data from the cursor' + "\n" +
' _help() this help ' + "\n" +
'Attributes: ' + "\n" +
' _database database object ' + "\n" +
'Example: ' + "\n" +
' > stmt = db._createStatement({ "query": "FOR c IN coll RETURN c" })' + "\n" +
' > cursor = stmt.execute() ' + "\n" +
' > documents = cursor.toArray() ' + "\n" +
' > cursor = stmt.execute() ' + "\n" +
' > while (cursor.hasNext()) { print(cursor.next()) } ';
ArangoQueryCursor.prototype._help = function () {
internal.print(helpArangoQueryCursor);
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return whether there are more results available in the cursor
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.hasNext = function () {
return this._hasNext;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return the next result document from the cursor
///
/// If no more results are available locally but more results are available on
/// the server, this function will make a roundtrip to the server
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.next = function () {
if (! this._hasNext) {
throw "No more results";
}
var result = this.data.result[this._pos];
this._pos++;
// reached last result
if (this._pos === this._count) {
this._hasNext = false;
this._pos = 0;
if (this._hasMore && this.data.id) {
this._hasMore = false;
// load more results
var requestResult = this._database._connection.PUT(this._baseurl(), "");
arangosh.checkRequestResult(requestResult);
this.data = requestResult;
this._count = requestResult.result.length;
if (this._pos < this._count) {
this._hasNext = true;
}
if (requestResult.hasMore !== undefined && requestResult.hasMore) {
this._hasMore = true;
}
}
}
return result;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief explicitly dispose the cursor
///
/// Calling this function will mark the cursor as deleted on the server. It will
/// therefore make a roundtrip to the server. Using a cursor after it has been
/// disposed is considered a user error
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.dispose = function () {
if (! this.data.id) {
// client side only cursor
return;
}
var requestResult = this._database._connection.DELETE(this._baseurl(), "");
arangosh.checkRequestResult(requestResult);
this.data.id = undefined;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return the total number of documents in the cursor
///
/// The number will remain the same regardless how much result documents have
/// already been fetched from the cursor.
///
/// This function will return the number only if the cursor was constructed
/// with the "doCount" attribute. Otherwise it will return undefined.
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.count = function () {
return this.data.count;
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return extra data stored for the cursor (if any)
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype.getExtra = function () {
return this.data.extra || { };
};
////////////////////////////////////////////////////////////////////////////////
/// @brief return baseurl for query cursor
////////////////////////////////////////////////////////////////////////////////
ArangoQueryCursor.prototype._baseurl = function () {
return "/_db/" + encodeURIComponent(this._dbName) +
"/_api/cursor/" + encodeURIComponent(this.data.id);
};