C++ language example

The environment and shared library classes provide information about the environment and libraries associated with an AE. This example takes one argument, an integer. If the integer equals 0, the AE outputs the environment it sees. If the integer equals 1, the AE looks the environment up as a library. If found, the path to the library is returned, otherwise NULL is returned:

#include <nzaefactory.hpp>
using namespace nz::ae;
static int run(nz::ae::NzaeFunction *aeFunc);
int main(int argc, char * argv[])
{
NzaeApiGenerator helper;
// The following line is only needed if a launcher is not used
helper.setName("testcapi");
for (int i=0; i < 2; i++) {
nz::ae::NzaeApi &api = helper.getApi(nz::ae::NzaeApi::FUNCTION);
run(api.aeFunction);
if (!helper.isRemote())
break;
}
return 0;
}
class MyHandler : public NzaeFunctionMessageHandler
{
public:
MyHandler() {
m_Once = false;
}
void doOnce(NzaeFunction& api) {
const NzaeMetadata& meta = api.getMetadata();
if (meta.getOutputColumnCount() != 1 ||
meta.getOutputType(0) != NzaeDataTypes::NZUDSUDX_VARIABLE) {
throw NzaeException("expecting one output column of type string");
}
if (meta.getInputColumnCount() != 2) {
throw NzaeException("expecting at least two input columns");
}
if (meta.getInputType(0) != NzaeDataTypes::NZUDSUDX_FIXED &&
meta.getInputType(0) != NzaeDataTypes::NZUDSUDX_VARIABLE) {
throw NzaeException("first input column expected to be a string
type");
}
if (meta.getInputType(1) != NzaeDataTypes::NZUDSUDX_INT32) {
throw NzaeException("second input column expected to be int32 type");
}
m_Once = true;
}
void evaluate(NzaeFunction& api, NzaeRecord &input, NzaeRecord &result) {
if (!m_Once)
doOnce(api);
NzaeField &field = input.get(0);
if (field.isNull())
throw NzaeException("first input column may not be null");
NzaeStringField &sf = (NzaeStringField&) input.get(0);
std::string strop = (std::string)sf;
NzaeField &field2 = input.get(1);
if (field2.isNull())
throw NzaeException("second input column may not be null");
NzaeInt32Field &inf = (NzaeInt32Field&) input.get(1);
int type = (int32_t)inf;
NzaeStringField &of= (NzaeStringField&)result.get(0);
if (type == 0) {
// env
const NzaeEnvironment& env = api.getEnvironment();
const char* val = env.getValue(strop.c_str());
if (!val)
of.setNull(true);
else
of = std::string(val);
}
else {
const NzaeLibrary& libs = api.getLibrary();
const NzaeLibrary::NzaeLibraryInfo *info =
libs.getLibraryInfo(strop.c_str(), false ,
NzaeLibrary::NzaeLibrarySearchBoth);
if (!info)
of.setNull(true);
else
of = info->libraryFullPath;
}
}
bool m_Once;
};
static int run(NzaeFunction *aeFunc)
{
aeFunc->run(new MyHandler());
return 0;
}

Use the standard compilation:

$NZ_EXPORT_DIR/ae/utilities/bin/compile_ae --language cpp --template compile \
--exe envae --compargs "-g -Wall" --linkargs "-g" env.cpp --version 3

Note that the output from this example is specific to the environment. Therefore, your actual output will resemble, but not match, the following text.

SELECT * FROM TABLE WITH FINAL(envae('inza..libnzaeadapters', 1));
VAL
-----------------------------------------------------------------------
/nz/data.1.0/base/1/library/237951/host/libnzaeadapters.so
(1 row)
SELECT * FROM TABLE WITH FINAL(envae('libnzaeadapters2', 1));
VAL
-----
(1 row)
SELECT * FROM TABLE WITH FINAL(envae('NZAE_DYNAMIC_ENVIRONMENT', 0));
VAL
-----
0
(1 row)
SELECT * FROM TABLE WITH FINAL(envae('NZAE_DYNAMIC_ENVIRONMENT2', 0));
VAL
-----
(1 row)