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mongodb/bson/bsondemo/bsondemo.cpp
2011-01-04 00:40:41 -05:00

108 lines
3.1 KiB
C++

/** @file bsondemo.cpp
Example of use of BSON from C++.
Requires boost (headers only).
Works headers only (the parts actually exercised herein that is - some functions require .cpp files).
*/
/*
* Copyright 2010 10gen Inc.
*
* 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.
*/
#include "../bson.h"
#include <iostream>
#include <vector>
using namespace std;
using namespace bson;
void iter(bo o) {
/* iterator example */
cout << "\niter()\n";
for( bo::iterator i(o); i.more(); ) {
cout << ' ' << i.next().toString() << '\n';
}
}
int main() {
cout << "build bits: " << 8 * sizeof(char *) << '\n' << endl;
/* a bson object defaults on construction to { } */
bo empty;
cout << "empty: " << empty << endl;
/* make a simple { name : 'joe', age : 33.7 } object */
{
bob b;
b.append("name", "joe");
b.append("age", 33.7);
b.obj();
}
/* make { name : 'joe', age : 33.7 } with a more compact notation. */
bo x = bob().append("name", "joe").append("age", 33.7).obj();
/* convert from bson to json */
string json = x.toString();
cout << "json for x:" << json << endl;
/* access some fields of bson object x */
cout << "Some x things: " << x["name"] << ' ' << x["age"].Number() << ' ' << x.isEmpty() << endl;
/* make a bit more complex object with some nesting
{ x : 'asdf', y : true, subobj : { z : 3, q : 4 } }
*/
bo y = BSON( "x" << "asdf" << "y" << true << "subobj" << BSON( "z" << 3 << "q" << 4 ) );
/* print it */
cout << "y: " << y << endl;
/* reach in and get subobj.z */
cout << "subobj.z: " << y.getFieldDotted("subobj.z").Number() << endl;
/* alternate syntax: */
cout << "subobj.z: " << y["subobj"]["z"].Number() << endl;
/* fetch all *top level* elements from object y into a vector */
vector<be> v;
y.elems(v);
cout << v[0] << endl;
/* into an array */
list<be> L;
y.elems(L);
bo sub = y["subobj"].Obj();
/* grab all the int's that were in subobj. if it had elements that were not ints, we throw an exception
(capital V on Vals() means exception if wrong type found
*/
vector<int> myints;
sub.Vals(myints);
cout << "my ints: " << myints[0] << ' ' << myints[1] << endl;
/* grab all the string values from x. if the field isn't of string type, just skip it --
lowercase v on vals() indicates skip don't throw.
*/
vector<string> strs;
x.vals(strs);
cout << strs.size() << " strings, first one: " << strs[0] << endl;
iter(y);
return 0;
}