Bug 416703 Mongodb : Display correctly the Number data type
data/org.eclipse.birt.data.oda.mongodb/src/org/eclipse/birt/data/oda/mongodb/internal/impl/MDbMetaData.java
/**
     * Find the FieldMetaData of each field specified by its full name. 
     * @param fieldFullNames    a list of fields in their full name.
     * @param fromDocMetaData   the metadata of documents found in a collection
     * @return  a flattened Map of each field's full name with its corresponding FieldMetaData.
     *          If a field name is not found in the specified DocumentsMetaData, 
     *          no entry is put in the returned Map.
     */
    public static Map<String,FieldMetaData> flattenFieldsMetaData( List<String> fieldFullNames,
            DocumentsMetaData fromDocMetaData )
    {
        if( fieldFullNames.isEmpty() )
            return Collections.emptyMap();  
        
        Map<String,FieldMetaData> resultFieldsMD = new LinkedHashMap<String,FieldMetaData>(fieldFullNames.size());
        for( String fieldFullName : fieldFullNames )
        {
            FieldMetaData fieldMD = findFieldByFullName( fieldFullName, fromDocMetaData );
            if( fieldMD != null )
                resultFieldsMD.put( fieldFullName, fieldMD );
        }
        return resultFieldsMD;
    }
    /**
     * Flatten all the fields, including nested ones, in the specified DocumentsMetaData into the specified Map.
     * @param fromDocMetaData   the metadata of documents found in a collection
     * @param toResultFieldsMD  the Map to which append the entries for all fields in the specified DocumentsMetaData
     * @return  a flattened Map of each field's full name with its corresponding FieldMetaData.
     */
    public static Map<String,FieldMetaData> flattenFieldsMetaData( DocumentsMetaData fromDocMetaData,