public Object putNodeMetaData(Object key, Object value) {
        if (key == null) throw new GroovyBugError("Tried to set meta data with null key on " + this + ".");
        if (metaDataMap == null) {
            metaDataMap = new ListHashMap();
        }
        return metaDataMap.put(key, value);
    }
public Object putNodeMetaData ( Object key , Object value ) { if ( key == null ) throw new GroovyBugError ( "Tried to set meta data with null key on " + this + "." ) ; if ( metaDataMap == null ) { metaDataMap = new ListHashMap ( ) ; } return metaDataMap . put ( key , value ) ; }
Sets the node meta data but allows overwriting values.

@param key   - the meta data key
@param value - the meta data value
@return the old node meta data value for this key
@throws GroovyBugError if key is null