com.cerner.beadledom.jackson.filter

Class FieldFilter

java.lang.Object

com.cerner.beadledom.jackson.filter.FieldFilter

public class FieldFilter
extends Object

A Jackson filter that will weed out fields from a provided String.

The filter will keep only the fields specified. Fields are comma delimited and nested fields can be referenced by their hierarchical field address. This is exemplified by the following:

     id,name,inner_model/name,inner_model2/embedded_inner/id,list_model/id
 

This will result in producing the following json:

     {
         "id": "id1",
         "name": "name1",
         "inner_model" : {
             "name" : "inner_name1"
         },
         "inner_model2" : {
             "embedded_inner" : {
                 "id" : "embedded_id1"
             }
         },
         "list_model" : [
              {
                  "id" : "elem1"
              },
              {
                  "id" : "elem2"
              }
         ]
     }
 

Using the above example, if you want filtering to be provided for embedded_inner, you'd need to provide the string:

     inner_model2/embedded_inner
 

This would serialize the entire object for key "inner_model2"/"embedded_inner".

Note: json fields containing a '/' character are NOT supported by this filter at this time.

Field Summary

Fields

Modifier and Type	Field and Description
static FieldFilter	UNFILTERED_FIELD

Method Summary

Modifier and Type	Method and Description
protected void	addField(String field) Adds a field to be filtered for this FieldFilter.
static FieldFilter	create(String fieldParam) Creates a new FieldFilter to handle empty or null params.
protected Map<String,FieldFilter>	getFilters()
boolean	hasFilters() Returns true if this FieldFilter contains filters, false otherwise.
void	writeJson(com.fasterxml.jackson.core.JsonParser parser, com.fasterxml.jackson.core.JsonGenerator jgen) Writes the json from the parser onto the generator, using the filters to only write the objects specified.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

UNFILTERED_FIELD

public static final FieldFilter UNFILTERED_FIELD

Method Detail

create

public static FieldFilter create(String fieldParam)

Creates a new FieldFilter to handle empty or null params.

Parameters:

fieldParam - comma separated list of fields to keep when executing the filter; should be in the format"id,inner_model/id,other_thing" corresponding to field names in the JSON

Returns:

a new FieldFilter to be applied to JSON

addField

protected void addField(String field)

Adds a field to be filtered for this FieldFilter.

hasFilters

public boolean hasFilters()

Returns true if this FieldFilter contains filters, false otherwise.

getFilters

protected Map<String,FieldFilter> getFilters()

writeJson

public void writeJson(com.fasterxml.jackson.core.JsonParser parser,
                      com.fasterxml.jackson.core.JsonGenerator jgen)
               throws IOException

Writes the json from the parser onto the generator, using the filters to only write the objects specified.

Parameters:

parser - JsonParser that is created from a Jackson utility (i.e. ObjectMapper)

jgen - JsonGenerator that is used for writing json onto an underlying stream

Throws:

com.fasterxml.jackson.core.JsonGenerationException - exception if Jackson throws an error while iterating through the JsonParser

IOException - if en error occurs while Jackson is parsing or writing json