Unexpected data when using Camel-xstream and Camel-velocity in dependencies

[jklemm]

Hi,

When I put camel-xstream and camel-velocity components in dependencies POM, the code below return XML data with strange elements.

Code:

from("direct:SQL_EXEC")

.process(

new Processor() {

public void process(Exchange exchange) throws Exception {

List<String> params = new ArrayList<String>();

params.add("ABCDEFG");

exchange.getOut().setBody(params, List.class);

}

}

)

.to("sql: SELECT * FROM TABLE WHERE COLUMN = #)

.marshal().xstream()

Result with ONLY camel-xstream in dependencies POM:

INFO: Exchange[BodyType:byte[], Body:<?xml version="1.0" ?><list><linked-hash-map><entry><string>CODCLI</string><string>ABCDEFG</string></entry><entry><string>UNDNEG</string><string>ABC</string></entry><entry><string>SALDOCR</string><big-decimal>12345678.00</big-decimal></entry><entry><string>IND01</string><string>A</string></entry></linked-hash-map></list>]

Simple and clean....

Now, the Result with camel-xstream and camel-velocity in dependencies POM..

INFO: Exchange[BodyType:byte[], Body:<?xml version="1.0" ?><list><org.apache.commons.collections.map.ListOrderedMap serialization="custom"><unserializable-parents></unserializable-parents><org.apache.commons.collections.map.ListOrderedMap><default><insertOrder><string>CODCLI</string><string>UNDNEG</string><string>SALDOCR</string><string>IND01</string></insertOrder></default><org.apache.commons.collections.map.CaseInsensitiveMap serialization="custom"><unserializable-parents></unserializable-parents><org.apache.commons.collections.map.CaseInsensitiveMap><default></default><float>0.75</float><int>8</int><int>4</int><string>ind01</string><string>A</string><string>undneg</string><string>ABC</string><string>codcli</string><string>ABCDEFG</string><string>saldocr</string><big-decimal>12345678.00</big-decimal></org.apache.commons.collections.map.CaseInsensitiveMap></org.apache.commons.collections.map.CaseInsensitiveMap></org.apache.commons.collections.map.ListOrderedMap></org.apache.commons.collections.map.ListOrderedMap></list>]

Looks too strange and complex to Map...

So, Is this a bug ?

Thanks,

[janstey]

Tracked this down to a method in org.springframework.core.CollectionFactory

public static Map createLinkedCaseInsensitiveMapIfPossible(int initialCapacity) {
    if (commonsCollections3Available) {
        logger.trace("Creating [org.apache.commons.collections.map.ListOrderedMap/CaseInsensitiveMap]");
        return CommonsCollectionFactory.createListOrderedCaseInsensitiveMap(initialCapacity);
    }
    else {
        logger.debug("Falling back to [java.util.LinkedHashMap] for linked case-insensitive map");
        return new LinkedHashMap(initialCapacity);
    }
}

So, it uses Apache commons-collections if it is available on the classpath. This is a feature of the Spring Framework. Velocity uses commons-collections so it introduces the behavior we are seeing. There are two options I can think of here to get back the nice XML format you had before...

(1) See if Velocity works without commons-collections on the classpath... this is a long shot

(2) Add in a custom processor to your route that will take the ListOrderedMap from commons-collections and instantiate a new LinkedHashMap from the Java runtime. Something like

from("direct:SQL_EXEC")
...
.to("sql: SELECT * FROM TABLE WHERE COLUMN = #")
.process(new Processor() {
    public void process(Exchange exchange) throws Exception {
        // create your new map here
    }
}).marshal().xstream()
...

Cheers,

Jon

[jklemm]

So,

The option 2

(2) Add in a custom processor to your route that will take the ListOrderedMap from commons-collections and instantiate a new LinkedHashMap from the Java runtime.

I don't understand how to convert the sql result with a Custom Processor...

I try

.convertBodyTo(LinkedHashMap.class)

.marshal().xstream()

but it fails.

Can you help me ?

Thanks,

[janstey]

The DSL method convertBodyTo(LinkedHashMap.class) doesn't work because this is not a common conversion supported by Camel (or anything else probably ). You can do this with a custom processor like so

from("direct:SQL_EXEC")
...
.to("sql: SELECT * FROM TABLE WHERE COLUMN = #")
.process(new Processor() {
    public void process(Exchange exchange) throws Exception {
        Object body = exchange.getIn().getBody();                        
        if (body instanceof ListOrderedMap) {
            ListOrderedMap oldMap = (ListOrderedMap) body;                     
            LinkedHashMap newMap = ... // create newMap from oldMap                          
            exchange.getIn().setBody(newMap);
        }                        
    }}).marshal().xstream()
...

Of course, you'll need to fill in the blanks where I say "create newMap from oldMap".

Cheers,

Jon