At work one of our developers is programming an ecommerce store against a Java API written by a third party. Said Java API returns a TreeMap object from a method and when you try to access that TreeMap object in any fashion, you’ll get an error, specifically:

“Error casting an object of type java.lang.Integer to an incompatible type. This usually indicates a programming error in Java, although it could also mean you have tried to use a foreign object in a different way than it was designed.”

What we’ve concluded is that ColdFusion attempts to cast any and all Java classes that implement the Map interface to:

coldfusion.runtime.Struct

which is of type java.util.Hashtable. Unfortunately, a TreeMap uses an Object (in this case an Integer) as the key. ColdFusion structures can only use strings as the key. The takeaway is that this is a ‘feature’ of ColdFusion, it’s nice that it attempts to transform collection type objects into the native ColdFusion structure type. In this specific case, it’s more of a hindrance. The workaround is to create your own Java wrapper that takes the TreeMap, loops over all the keys, inserting each into a Vector and then return the Vector to ColdFusion, which turns that into a structure.

In case you don’t feel comfortable going to sleep at night without seeing the code, here’s an example Java class that returns a simple TreeMap:

import java.util.*;
public class TreeMapTest {
   public static TreeMap getTree() {
      TreeMap t = new TreeMap();
      t.put(new Integer(131000), “product”);
      return t;
   }
}

Compile that and then drop it into your [cfusionmx]\wwwroot\WEB-INF\lib\ directory. You can use this script to test it:

<cfscript>
   tmt = createObject(“java”, “TreeMapTest”);
   WriteOutput(“tmt is of type ” & tmt.getClass());
   treeMap = tmt.getTree();
   WriteOutput(“treeMap is of type ” & treeMap.toString()); // you get an error here
</cfscript>

I’d be very very interested in hearing about any ways that you know of to get around something like this without having to write a wrapper class. And for you Macromedia ColdFusion guys, it might be a nice (albeit probably rarely used) feature to be able to maintain the Java type of an object by using some function, ( ie: maintainType() or some such).

By the way, if you’re interested in knowing more about using Java and ColdFusion together, Terry Ford has written a great article here entitled “Using Java and J2EE Elements in ColdFusion MX Applications”.

Doug posted a query on the cfguru list asking how he might retrieve whois information using ColdFusion. I mentioned that there are numerous tags (search on google if you want to see them), but that it’s pretty easy to do within ColdFusion if you drop the Jakarta Commons/Net jar into your ColdFusion lib directory (cfusionmx/wwwroot/WEB-INF/lib/):

<cfscript>
  whois = createObject(“java”, “org.apache.commons.net.WhoisClient”);
  whois.init();
  whois.connect(“192.149.252.43”); // whois.arin.net
  WriteOutput(whois.query(“204.212.42.4”)); // your random ip address here
  whois.disconnect();
</cfscript>

Note that the whois service works over port 43, so your server must have outbound access to port 43 (if you’re accessing a server outside your own network, performance would presumably be much better if you ran your own whois server internally).

Just got back from a trip to California & Oregon for a family wedding to find that the article I wrote for ColdFusion Developer’s Journal went live… check it out when you have a chance!

Sam posted some CF code that gives you the ability to upload a file to a web server without using CFFILE (ie: he uses Java instead): Handling file uploads without CFFILE.

On a related note, Oreilly has an article (Using the Jakarta Commons) that (will) introduce(s) each component in the Jakarta Commons library. Probably would have been better to use the tried and tested FileUpload component from the Commons lib, but that would have required the jar file be present in ColdFusion’s classpath.

I’ve read emails [1] [2] from a couple different people on the various email lists that CFMX can’t use sockets…. which is true in the sense that CFMX doesn’t have a <cfsocket> tag, but not true in the sense that you can’t easily use sockets in ColdFusion. I banged around this morning for a bit and came up with this example, which does an HTTP request of www.mindseye.com using a java.net.Socket object and then loops over the returned headers and prints them out to the screen:

<cfscript>
// get a socket object
socket = CreateObject(“java”, “java.net.Socket”);

// call the Socket constructor
socket.init(“www.mindseye.com”, 80);

// get a PrintWriter object
printWriter = CreateObject(“java”, “java.io.PrintWriter”);

// call the PrintWriter constructor
printWriter.init(socket.getOutputStream(), true);

// get an InputStreamReader object
inputsr = CreateObject(“java”, “java.io.InputStreamReader”);

// call the InputStreamReader constructor
inputsr.init(socket.getInputStream());

// get a BufferedReader object
input = CreateObject(“java”, “java.io.BufferedReader”);

// call the BufferedReader constructor
input.init(inputsr);

// request the homepage
printWriter.println(‘GET /index.cfm’);
      
// loop over result by reading line by line
run = true;
while (run) {
   // read the result line by line
   resultLine = input.readLine();
   if (len(resultLine) GT 0) {
      WriteOutput(“Header: ” & resultLine & “<br />”);
   } else {
      run = false;
   }
}   
</cfscript>

You could easily modify this to write xml to a server socket:

printWriter.println(‘<order orderType=”quote” customerType=”RETAIL” orderNumber=”1234″ orderDate=”2003-03-21″>’);
printWriter.println(‘<shipment ID=”1″ city=”Boston” state=”MA” zip=”02210″>’);
printWriter.println(‘<line_item ID=”1″ SKU=”18JK23″ category=”GSHOE” quantity=”2″ total=”39.90″ />’);
printWriter.println(‘</shipment>’);
printWriter.println(‘</order>’);

or do a variety of other useful things like send SMTP email, do DNS lookups, or send SOAP packets.