org.apache.uima.json

Class JsonCasSerializer

java.lang.Object

org.apache.uima.json.JsonCasSerializer

public class JsonCasSerializer
extends Object

CAS serializer for JSON formats.

Writes a CAS in a JSON format.

To use,

• create an instance of this class,
• (optionally) configure the instance, and then
• call serialize on the instance, optionally passing in additional parameters.

After the 1st 2 steps, the serializer instance may be used for multiple calls (on multiple threads) to the 3rd serialize step, if all calls use the same configuration.

There are "convenience" static serialize methods that do these three steps for common configurations.

Parameters can be configured in this instance (I), and/or as part of the serialize(S) call.

The parameters that can be configured are:

• (S) The CAS to serialize
• (S) where to put the output - an OutputStream, Writer, or File
• (I,S) a type system - (default null) if supplied, it is used to "filter" types and features that are serialized. If provided, only those that exist in the passed in type system are included in the serialization
• (I,S) a flag for prettyprinting - default false (no prettyprinting)

For Json serialization, additional configuration from the Jackson implementation can be configured

on 2 associated Jackson instances:

• JsonFactory
• JsonGenerator

using the standard Jackson methods on the associated JsonFactory instance; see the Jackson JsonFactory and JsonGenerator javadocs for details.

These 2 Jackson objects are settable/gettable from an instance of this class. They are created if not supplied by the caller.

Once this instance is configured, the serialize method is called to serialized a CAS to an output.

Instances of this class must be used on only one thread while configuration is being done; afterwards, multiple threads may use the configured instance, to call serialize.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JsonCasSerializer.JsonContextFormat The serialization can optionally include context information in addition to the feature structures.

Constructor Summary

Constructors

Constructor and Description
JsonCasSerializer() Creates a new JsonCasSerializer

Method Summary

Modifier and Type	Method and Description
static void	jsonSerialize(CAS aCAS, Object output) Serializes a CAS using JSON
static void	jsonSerialize(CAS aCAS, TypeSystem aTargetTypeSystem, Object output) Serializes a CAS to an output (File, OutputStream, XMI stream, or Writer).
static void	jsonSerialize(CAS aCAS, TypeSystem aTargetTypeSystem, Object output, boolean aPrettyPrint, Marker aMarker, XmiSerializationSharedData sharedData) Serializes a Delta CAS to an output (File, Writer, or OutputStream).
void	serialize(CAS cas, org.apache.uima.json.impl.JsonContentHandlerJacksonWrapper jch) Serialize a Cas to an Output configured in the passed in JsonContentHandlerJacksonWrapper Constructs a new CasDocSerializer instance to do the serialization, configured using this class's Delta marker setting (if any)
void	serialize(CAS cas, org.apache.uima.json.impl.JsonContentHandlerJacksonWrapper jch, XmiSerializationSharedData sharedData, Marker marker)
void	serialize(CAS cas, Object output) Serialize a Cas to an Output, using configurations set on this instance.
void	serialize(CAS cas, Object output, XmiSerializationSharedData sharedData, Marker marker)
JsonCasSerializer	setErrorHandler(ErrorHandler eh) set an error handler to receive information about errors
JsonCasSerializer	setFilterTypes(org.apache.uima.cas.impl.TypeSystemImpl ts) pass in a type system to use for filtering what gets serialized; only those types and features which are defined this type system are included.
JsonCasSerializer	setJsonContext(JsonCasSerializer.JsonContextFormat format) sets which Json context format to use when serializing
JsonCasSerializer	setJsonFactory(com.fasterxml.jackson.core.JsonFactory jsonFactory) set which JsonFactory instance to use; if null, a new instance is used this can be used to preconfigure the JsonFactory instance
JsonCasSerializer	setOmit0Values(boolean omitDefaultValues)
JsonCasSerializer	setPrettyPrint(boolean pp) set or reset the pretty print flag (default is false)
JsonCasSerializer	setStaticEmbedding() Sets static embedding mode
JsonCasSerializer	setTypeSystemReference(String reference)

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonCasSerializer

public JsonCasSerializer()

Creates a new JsonCasSerializer

Method Detail

jsonSerialize

public static void jsonSerialize(CAS aCAS,
                                 Object output)
                          throws IOException

Serializes a CAS using JSON

Parameters:

aCAS - CAS to serialize.

output - a File, OutputStream or Writer to which to write the XMI document

Throws:

IOException - if there was an IOException

jsonSerialize

public static void jsonSerialize(CAS aCAS,
                                 TypeSystem aTargetTypeSystem,
                                 Object output)
                          throws IOException

Serializes a CAS to an output (File, OutputStream, XMI stream, or Writer). The supplied typesystem filters the output

Parameters:

aCAS - CAS to serialize.

aTargetTypeSystem - type system used for filtering what gets serialized. Any types or features not in the target type system will not be serialized. A null value indicates no filtering, that is, that all types and features will be serialized.

output - output (File, OutputStream, or Writer) to which to write the JSON document

Throws:

IOException - if there was an IOException

jsonSerialize

public static void jsonSerialize(CAS aCAS,
                                 TypeSystem aTargetTypeSystem,
                                 Object output,
                                 boolean aPrettyPrint,
                                 Marker aMarker,
                                 XmiSerializationSharedData sharedData)
                          throws IOException

Serializes a Delta CAS to an output (File, Writer, or OutputStream). This version of this method allows many options to be configured.

Parameters:

aCAS - CAS to serialize.

aTargetTypeSystem - type system to which the produced XMI will conform. Any types or features not in the target type system will not be serialized. A null value indicates that all types and features will be serialized.

output - File, Writer, or OutputStream to which to write the JSON document

aPrettyPrint - if true the JSON output will be formatted with newlines and indenting. If false it will be unformatted.

aMarker - an optional object used to determine which FeatureStructures and modifications were created after the mark was set. Used to serialize a Delta CAS consisting of only new FSs and views and preexisting FSs and Views that have been modified. If null, full serialization is done. See the JavaDocs for Marker for details.

sharedData - optional, used for delta serialization (not yet supported)

Throws:

IOException - if there was an IOException

serialize

public void serialize(CAS cas,
                      Object output)
               throws IOException

Serialize a Cas to an Output, using configurations set on this instance. Constructs a JsonContentHandlerJacksonWrapper, using configured JsonFactory and prettyprint settings if any

Parameters:

cas - - the CAS to serialize

output - - where the output goes, an OutputStream, Writer, or File

Throws:

IOException - if there was an IOException

serialize

public void serialize(CAS cas,
                      Object output,
                      XmiSerializationSharedData sharedData,
                      Marker marker)
               throws IOException

Throws:

IOException

serialize

public void serialize(CAS cas,
                      org.apache.uima.json.impl.JsonContentHandlerJacksonWrapper jch)
               throws IOException

Serialize a Cas to an Output configured in the passed in JsonContentHandlerJacksonWrapper Constructs a new CasDocSerializer instance to do the serialization, configured using this class's Delta marker setting (if any)

Parameters:

cas - The CAS to serialize

jch - the configured content handler

Throws:

IOException - if there was an IOException

serialize

public void serialize(CAS cas,
                      org.apache.uima.json.impl.JsonContentHandlerJacksonWrapper jch,
                      XmiSerializationSharedData sharedData,
                      Marker marker)
               throws IOException

Throws:

IOException

setPrettyPrint

public JsonCasSerializer setPrettyPrint(boolean pp)

set or reset the pretty print flag (default is false)

Parameters:

pp - true to do pretty printing of output

Returns:

the original instance, possibly updated

setJsonFactory

public JsonCasSerializer setJsonFactory(com.fasterxml.jackson.core.JsonFactory jsonFactory)

set which JsonFactory instance to use; if null, a new instance is used this can be used to preconfigure the JsonFactory instance

Parameters:

jsonFactory - -

Returns:

the original instance, possibly updated

setFilterTypes

public JsonCasSerializer setFilterTypes(org.apache.uima.cas.impl.TypeSystemImpl ts)

pass in a type system to use for filtering what gets serialized; only those types and features which are defined this type system are included.

Parameters:

ts - the filter

Returns:

the original instance, possibly updated

setTypeSystemReference

public JsonCasSerializer setTypeSystemReference(String reference)

setErrorHandler

public JsonCasSerializer setErrorHandler(ErrorHandler eh)

set an error handler to receive information about errors

Parameters:

eh - the error handler

Returns:

the original instance, possibly updated

setStaticEmbedding

public JsonCasSerializer setStaticEmbedding()

Sets static embedding mode

Returns:

the original instance, possibly updated

setJsonContext

public JsonCasSerializer setJsonContext(JsonCasSerializer.JsonContextFormat format)

sets which Json context format to use when serializing

Parameters:

format - the format to use for the serialization Specifying the context flag also specifies all 3 subflags Specifying one of the subflags as true sets the context flag to true if it isn't already

Returns:

the original instance, possibly updated

setOmit0Values

public JsonCasSerializer setOmit0Values(boolean omitDefaultValues)