Creating a Multi-Dimensional Java Array from ColdFusion
I recently needed to create a multi-dimensional byte array from ColdFusion and pass it to a java class. I was unable to use javacast("byte[]", ...) because the code needed to be compatible with MX7. Initially, I constructed the array manually, using an old tip from Christian Cantrell's blog.
<cfscript>
// cfSearching: create a 3 x 20 byte array
byteClass = createObject("java", "java.lang.Byte").TYPE;
reflectArray = createObject("java","java.lang.reflect.Array");
arr1 = reflectArray.newInstance(byteClass, javacast("int", 20));
arr2 = reflectArray.newInstance(byteClass, javacast("int", 20));
arr3 = reflectArray.newInstance(byteClass, javacast("int", 20));
multiArray = arrayNew(1);
arrayAppend(multiArray, arr1);
arrayAppend(multiArray, arr2);
arrayAppend(multiArray, arr3);
// cfSearching: pass the array to the java object
myJavaObject.grabBytes(multiArray);
</cfscript>
This struck me as bit awkward, so I reviewed the API and realized there is a simpler way. The java.lang.reflect.Array class contains a second newInstance() method which accepts an int[] array of dimensions. So my final code was reduced to:
<cfscript>
byteClass = createObject("java", "java.lang.Byte").TYPE;
reflectArray = createObject("java","java.lang.reflect.Array");
arrayDimensions = listToArray("3,20");
multiArray = reflectArray.newInstance(byteClass, arrayDimensions);
myJavaObject.grabBytes(multiArray);
</cfscript>
I just thought I would post this tip in case it helps someone.
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2 comments:
I'm trying to do something similar to this, except with a multidimensional integer array.
I can see how your code works on the coldfusion side of things but what type did you use for the parameter in your grabBytes()java method?
Thanks in advance,
Odhran.
@Odhran,
With a 3-d array it was probably something like:
public static void someMethod(byte[][][] arr) {
...
}
Same concept for a 3-d int array:
public static void someMethod(int[][][] arr) {
...
}
-Leigh
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