{"id":452,"date":"2003-07-17T22:23:03","date_gmt":"2003-07-18T02:23:03","guid":{"rendered":"http:\/\/wordpress.cephas.net\/?p=452"},"modified":"2003-07-17T22:23:03","modified_gmt":"2003-07-18T02:23:03","slug":"java-collection-types-coldfusion","status":"publish","type":"post","link":"https:\/\/cephas.net\/blog\/2003\/07\/17\/java-collection-types-coldfusion\/","title":{"rendered":"Java Collection Types & ColdFusion"},"content":{"rendered":"

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<\/a> object from a method and when you try to access that TreeMap object in any fashion, you’ll get an error, specifically:<\/p>\n

“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.”<\/i><\/p>\n

What we’ve concluded is that ColdFusion attempts to cast any and all Java classes that implement the Map interface to:<\/p>\n

coldfusion.runtime.Struct<\/p>\n

which is of type java.util.Hashtable<\/a>. Unfortunately, a TreeMap uses an Object<\/a> (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<\/a> and then return the Vector to ColdFusion, which turns that into a structure. <\/p>\n

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:<\/p>\n

import java.util.*;
\npublic class TreeMapTest {
\n   public static TreeMap getTree() {
\n      TreeMap t = new TreeMap();
\n      t.put(new Integer(131000), “product”);
\n      return t;
\n   }
\n}<\/p>\n

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

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

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).<\/p>\n

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”<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

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 … Continue reading Java Collection Types & ColdFusion<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[],"_links":{"self":[{"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/posts\/452"}],"collection":[{"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/comments?post=452"}],"version-history":[{"count":0,"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/posts\/452\/revisions"}],"wp:attachment":[{"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/media?parent=452"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/categories?post=452"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cephas.net\/blog\/wp-json\/wp\/v2\/tags?post=452"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}