We Keep Coding

Geolocalization with Bing and Java

Can I use the Bing Maps API with Java for geolocation? I have the API key but I can't find anything on the net.
I've found a method with an Excel Macro that works but isn't enough, I need a java console script to do it.
Cheers, Damiano.

There doesn't appear to be any official way to make use of the Maps API in Java.
However, there is an unofficial Java wrapper for the API located here. This hasn't been updated in a while, so there's no guarantee it will still work, but it should be a good starting point for implementing geocoding requests.
There is also a method for implementing reverse-geocoding requests in the same wrapper at client.reverseGeocode().
import net.virtualearth.dev.webservices.v1.common.GeocodeResult;
import net.virtualearth.dev.webservices.v1.geocode.GeocodeRequest;
import net.virtualearth.dev.webservices.v1.geocode.GeocodeResponse;
import com.google.code.bing.webservices.client.BingMapsWebServicesClientFactory;
import com.google.code.bing.webservices.client.geocode.BingMapsGeocodeServiceClient;
import com.google.code.bing.webservices.client.geocode.BingMapsGeocodeServiceClient.GeocodeRequestBuilder;
public class BingMapsGeocodeServiceSample {
public static void main(String[] args) throws Exception {
BingMapsWebServicesClientFactory factory = BingMapsWebServicesClientFactory.newInstance();
BingMapsGeocodeServiceClient client = factory.createGeocodeServiceClient();
GeocodeResponse response = client.geocode(createGeocodeRequest(client));
printResponse(response);
}
private static void printResponse(GeocodeResponse response) {
for (GeocodeResult result : response.getResults().getGeocodeResult()) {
System.out.println(result.getDisplayName());
}
}
private static GeocodeRequest createGeocodeRequest(BingMapsGeocodeServiceClient client) {
GeocodeRequestBuilder builder = client.newGeocodeRequestBuilder();
builder.withCredentials("xxxxxx", null);
builder.withQuery("1 Microsoft Way, Redmond, WA");
// builder.withOptionsFilter(Confidence.HIGH);
return builder.getResult();
}
}

Both ways, java <=> python, communication using py4j

I am using py4j for communication between python and java.I am able to call python method from java side. But from python I am not able to send any object or call java method. Here is the code i have tried.
My java code:
public interface IHello {
public String sayHello();
public String sayHello(int i, String s);
// public String frompython();
}
//ExampleClientApplication.java
package py4j.examples;
import py4j.GatewayServer;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class ExampleClientApplication extends Thread {
public void run(){
System.out.println("thread is running...");
}
public static void main(String[] args) {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
GatewayServer.turnLoggingOff();
GatewayServer server = new GatewayServer();
server.start();
IHello hello = (IHello) server.getPythonServerEntryPoint(new Class[] { IHello.class });
try {
System.out.println("Please enter a string");
String str = br.readLine();
System.out.println(hello.sayHello(1, str));
} catch (Exception e) {
e.printStackTrace();
}
ExampleClientApplication t1 = new ExampleClientApplication();
t1.start();
//server.shutdown();
}
}
My python code :
class SimpleHello(object):
def sayHello(self, int_value=None, string_value=None):
print(int_value, string_value)
return "From python to {0}".format(string_value)
class Java:
implements = ["py4j.examples.IHello"]
# Make sure that the python code is started first.
# Then execute: java -cp py4j.jar
py4j.examples.SingleThreadClientApplication
from py4j.java_gateway import JavaGateway, CallbackServerParameters
simple_hello = SimpleHello()
gateway = JavaGateway(
callback_server_parameters=CallbackServerParameters(),
python_server_entry_point=simple_hello)

The send objects problem is easily solved by implementing a getter/eval method in the java interface that is implemented by python, which can then be called from java to get the variable that is requested. For an example have a look at the py4j implementation here: https://github.com/subes/invesdwin-context-python
Specifically see the get/eval method implementation here: https://github.com/subes/invesdwin-context-python/blob/master/invesdwin-context-python-parent/invesdwin-context-python-runtime-py4j/src/main/java/de/invesdwin/context/python/runtime/py4j/pool/internal/Py4jInterpreter.py
For the other way around, you would have to do same on the java gateway class and provide a get/eval method that can be called from python. The actual java code could be executed in a ScriptEngine for groovy and the result could be returned to python. (see http://docs.groovy-lang.org/1.8.9/html/groovy-jdk/javax/script/ScriptEngine.html)
Though it might be a better idea to decide about a master/slave role and only once input the parameters, then execute the code in python and retrieve the results once. Or the other way around if python should be leading. Thus you would reduce the communication overhead a lot. For a tighter integration without as much of a performance penalty as py4j incurs, you should have a look at https://github.com/mrj0/jep to directly load the python lib into the java process. Then each call is not as expensive anymore.

Call DLL from Java using JNA

I am new to accessing DLLs from Java using JNA. I need to access methods from a class within a DLL(written in .net). Form this sample DLL below, I am trying to get AuditID and Server ID. I am ending with the following error while I am running my code. Any guidance really appreciated.
/// Error ///
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'GetEnrollcontext': The specified procedure could not be found.
//DLL File Code//
SampleDLL.ProfileEnroll enrollcontext = new SampleDLL.ProfileEnroll();
enrollcontext.Url =” url”;
enrollcontext.AuditIdType = SampleDLL.ProfileId;
enrollcontext.AuditId = “22222222 “;
enrollcontext.ServerId = “server1”;
/// Java Code ///
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Structure;
import dllExtract.DLLExtractTest.SampleDLL.Enrollcontext;
public class SampleDLLExtract {
public interface SampleDLL extends Library {
SampleDLL INSTANCE = (SampleDLL) Native.loadLibrary("SampleDLL",
SampleDLL.class);
public static class Enrollcontext extends Structure {
public String auditId;
public String serverId;
}
void GetEnrollcontext(Enrollcontext ec); // void ();
}
public static void main(String[] args) {
SampleDLL sdll = SampleDLL.INSTANCE;
SampleDLL.Enrollcontext enrollContext = new SampleDLL.Enrollcontext();
sdll.GetEnrollcontext(enrollContext);
System.out.println(sdll.toString(sdll.GetEnrollcontext(enrollContext)));
}
}

in fact there is a solution for you to use C#, VB.NET or F# code via JNA in Java (and nothing else)! and it is also very easy to use:
https://www.nuget.org/packages/UnmanagedExports
with this package all you need to do is, add [RGiesecke.DllExport.DllExport] to your methods like that:
C# .dll Project:
[RGiesecke.DllExport.DllExport]
public static String yourFunction(String yourParameter)
{
return "CSharp String";
}
Java Project:
public interface jna extends Library {
jna INSTANCE = (jna) Native.loadLibrary("yourCSharpProject.dll", jna.class);
public String yourFunction(String yourParameter);
}
use it in the code:
System.out.println(jna.INSTANCE.yourFunction("nothingImportant"));
Viola!
As already mentioned it works very easy, but this solution has some limitations:
only available for simple datatypes as parameter & return values
no MethodOverloading available. yourFunction(String yourParameter) and yourFunction(String yourParameter, String yourSecondParameter) does not work! you have to name them differently
Use arrays as parameter or return values. (JNA offers StringArray, but I am not able to use them in C#) (maybe there is a solution, but I couldn't come up with one so far!)
if you export a method you can't call it internally in your C# code (simple to bypass that by the following:
.
[RGiesecke.DllExport.DllExport]
public static Boolean externalAvailable(String yourParameter)
{
return yourInternalFunction(yourParameter);
}
With C# it works great, with VB.NET and F# I have no experience.
hope this helps!

Executing script inside method with BeanShell

I'm not really sure how I can explain this, but here goes:
I want to be able to "insert" some commands into parts of my code which will be loaded from external files. To parse and execute these commands, I presumably have to use some scripting like BeanShell's eval method. The problem is that it doesn't seem to recognize the instance/method it's inside of. As a very basic example, I want to do something like
public void somethingHappens()
{
Foo foo = new Foo();
Interpreter i = new Interpreter();
i.eval("print(foo.getName());");
}
Is this possible? Should I use other scripting tools?

If you're using 1.6, you can use the built in JavaScript support.
The Java Scripting Programmer's Guide explains how to import Java classes into your script.
Code example 9 in this article explains how to pass objects into the script's scope.

Using beanshell, this is something you can try
package beanshell;
import bsh.EvalError;
import bsh.Interpreter;
public class DemoExample {
public static void main( String [] args ) throws EvalError {
Interpreter i = new bsh.Interpreter();
String usrIp = "if(\"abc\".equals(\"abc\")){"
+ "demoExmp.printValue(\"Rohit\");"
+ "}";
i.eval(""
+ "import beanshell.DemoExample;"
+ "DemoExample demoExmp = new beanshell.DemoExample();"
+ ""+usrIp);
}
public static void printValue(String strVal){
System.out.println("Printing Value "+strVal);
}
}

renaming DLL functions in JNA using StdCallFunctionMapper

I'm trying to use JNA with a DLL in Windows, so far I was able to successfully call a function called c_aa_find_devices(). But all the functions start with c_aa and I would like to rename it to find_devices().
From what I gather the way to do this is with StdCallFunctionMapper but I can't find the documentation of how to use it in an example (i.e. how to map a DLL function by name or by ordinal to a desired name in the wrapped Java library interface). Any suggestions on where the docs are?

A complete working example, using a function mapper.
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.NativeLibrary;
import com.sun.jna.win32.StdCallFunctionMapper;
import java.io.File;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
public class JnaTest {
static {
Map options = new HashMap();
options.
put(
Library.OPTION_FUNCTION_MAPPER,
new StdCallFunctionMapper() {
HashMap<String, String> map = new HashMap() {
{
put("testMethod", "testMethod#0");
}
};
#Override
public String getFunctionName(NativeLibrary library, Method method) {
String methodName = method.getName();
return map.get(methodName);
}
}
);
File LIB_FILE = new File("test.dll");
Native.register(NativeLibrary.getInstance(LIB_FILE.getAbsolutePath(), options));
}
private static native int testMethod();
public static void main(String[] args) {
testMethod(); // call the native method in the loaded dll with the function name testMethod#0
}
}

Using StdCallMapper won't do good - it is supposed to map werid windows std lib names that have embedded total byte lenght of parameters embedded as part of the name. Since it is done to std lib only (just guessing on that, but 99% you'r functions are not the case).
If your dll uses some common prefix on all functions you need just to use something like:
class Mapper implements FunctionMapper{
public String getFunctionName(NativeLibrary library, Method method) {
return GenieConnector.FUNCTION_PREFIX + method.getName();
}
}
Where GenieConnector.FUNCTION_PREFIX is that common prefix. Bear in mind that i implement FunctionMapper, not extend StdCallMapper

From the documentation you need to provide a FunctionMapper in the original call to loadLibrary that converts the name. However you also need to keep the standard call mapping so try something like the following:
Map options = new HashMap();
options.
put(
Library.OPTION_FUNCTION_MAPPER,
new StdCallFunctionWrapper() {
public String getFunctionName(NativeLibrary library, Method method) {
if (method.getName().equals("findDevices")
method.setName("c_aa_find_devices");
// do any others
return super.getFunctionName(library, method);
}
}
);
Native.loadLibrary(..., ..., options);

All JNA documentation is located at the primary web page, the JavaDoc overview, and the JavaDocs themselves.
The example above is the right idea, in that you need to tweak the function name returned by the generic StdCallFunctionMapper (assuming you're using the stdcall calling convention). However, Method.setName() doesn't exist and you wouldn't want to call it if it did. You'll need to get the String result and replace the Java function name within it with the target native name, e.g.
name = super.getFunctionName();
name = name.replace("find_devices", "c_aa_find_devices");
More generically, you can simply tack on a "c_aa_" prefix to the returned name (or after any leading underscore), since stdcall decorations are at the end of the name.