[CAMEL-9584] LevelDB - Allow serializable objects in headers

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.16.1
• Fix Version/s: 2.17.0
• Component/s: camel-core, camel-leveldb

Environment

all platforms (linux and windows)

• Estimated Complexity: Novice
• External issue URL: http://camel.465427.n5.nabble.com/LevelDB-and-Serializable-Bug-td5777469.html#a5777471
• Assignee: Andrea Cosentino
• Reporter: Hubertus Willuhn
• Created: 10/Feb/16 07:19
• Updated: 18/Feb/16 07:54
• Resolved: 18/Feb/16 07:54

Description

I am using the LevelDB repository of Camel to store exchanges while aggregating.

Every exchange contains a simple POJO in the header that serves as aggregation predicate.

My POJO-class got the following signature:

public class ID implements Cloneable, Serializable { ...

and only 3 properties:

private final String org;
private final String type;
private String key;

But Camel don't want to serialize my class because:

WARN org.apache.camel.impl.DefaultExchangeHolder – Exchange in headers containing key: RECID with object: CEN-PRJ-22 of type: com.domain.ID is not valid header type, it will be excluded by the holder.

I look into the "DefaultExchangeHolder" class and this function seems to be the problem:

protected static Object getValidHeaderValue(String headerName, Object headerValue) { ...

This function only allows default Java objects (like String).
But it should be possible to persist any "Serializable".

In the official documentation of LevelDB (http://camel.apache.org/leveldb.html) you can read:

LevelDBAggregationRepository will only preserve any Serializable compatible data types. If a data type is not such a type its dropped and a WARN is logged. And it only persists the Message body and the Message headers. The Exchange properties are not persisted.