Package com.adaptris.core.json.streaming

Class JsonPathStreamingService

java.lang.Object

com.adaptris.core.ServiceImp

com.adaptris.core.services.path.json.JsonPathServiceImpl

com.adaptris.core.json.streaming.JsonPathStreamingService

All Implemented Interfaces:

AdaptrisComponent, ComponentLifecycle, ComponentLifecycleExtension, MessageEventGenerator, Service, StateManagedComponent

@ComponentProfile(summary="Extract a value from a large JSON document",
                  tag="service,transform,json,metadata,streaming,large")
public class JsonPathStreamingService
extends com.adaptris.core.services.path.json.JsonPathServiceImpl

This service allows you to search JSON content and the results are then set back into the message. The advantage of this implementation is that it doesn't need to parse the entire JSON document and so is able to handle arbitrarily large documents.

The searching works in much the same way as XPath, for more information on how to build a JSON path see the JSONPath documentation and the JSON Surfer documentation.

For example, if you have a message with the following payload:

 
 {
 "store": {
 "book": [ {
 "category": "reference",
 "author": "Nigel Rees",
 "title": "Sayings of the Century",
 "price": 8.95
 }, {
 "category": "fiction",
 "author": "Evelyn Waugh",
 "title": "Sword of Honour",
 "price": 12.99
 }, {
 "category": "fiction",
 "author": "Herman Melville",
 "title": "Moby Dick",
 "isbn": "0-553-21311-3",
 "price": 8.99
 }, {
 "category": "fiction",
 "author": "J. R. R. Tolkien",
 "title": "The Lord of the Rings",
 "isbn": "0-395-19395-8",
 "price": 22.99
 } ],
 "bicycle": {
 "color": "red",
 "price": 19.95
 }
 },
 "expensive": 10
 }
 
 

You could configure 2 target destinations, each one creating a new metadata item with the results of the specified search, like this;

 
 <json-path-streaming-service>
 <json-path-execution>
 <source class="constant-data-input-parameter">
 <value>$.store.book[0].title</value>
 </source>
 <target class="metadata-data-output-parameter">
 <metadata-key>metadata-key-1</metadata-key>
 </target>
 <suppress-path-not-found>true</suppress-path-not-found>
 </json-path-execution>
 <json-path-execution>
 <source class="constant-data-input-parameter">
 <value>$.store.book[1].title</value>
 </source>
 <target class="metadata-data-output-parameter">
 <metadata-key>metadata-key-2</metadata-key>
 </target>
 </json-path-execution>
 </json-path-streaming-service>
 
 

The first target above searches for the first book title, the second target searches for the second book title. Each target-destination will be executed in the order they are configured and therefore with the two targets shown here, your message, after the service has run, will include two new metadata items;

• metadata-key-1 = "Sayings of the Century"
• metadata-key-2 = "Sword of Honour"

Any results returned by this service will normally include the json brackets wrapping the returned value. However you can configure this service to unwrap the result for you, such that a value returned as "[myValue]" will now be returned as "myValue".
The default value is false, but to override simply configure the "unwrap";

 
 <json-path-service>
 <unwrap-json>true</unwrap-json>
 ...
 </json-path-service>
 
 

In the adapter configuration file this class is aliased as json-path-streaming-service which is the preferred alternative to the fully qualified classname when building your configuration.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	JsonPathStreamingService.Surfer

Field Summary

Fields inherited from class com.adaptris.core.services.path.json.JsonPathServiceImpl

executions, unwrapJson

Fields inherited from class com.adaptris.core.ServiceImp

log

Constructor Summary

Constructors

Constructor	Description
JsonPathStreamingService()
JsonPathStreamingService(DataInputParameter<java.io.InputStream> source, Execution... executions)
JsonPathStreamingService(DataInputParameter<java.io.InputStream> source, java.util.List<Execution> executions)

Method Summary

Modifier and Type	Method	Description
void	doService(AdaptrisMessage message)	.
@NonNull DataInputParameter<java.io.InputStream>	getSource()	The source for executing the jsonpath against.
@NonNull JsonPathStreamingService.Surfer	getSurfer()	The JSON surfer implementation to use.
void	prepare()
void	setSource(@NonNull DataInputParameter<java.io.InputStream> source)	The source for executing the jsonpath against.
void	setSurfer(@NonNull JsonPathStreamingService.Surfer surfer)	The JSON surfer implementation to use.

Methods inherited from class com.adaptris.core.services.path.json.JsonPathServiceImpl

closeService, convertIfNull, getExecutions, getUnwrapJson, initService, setExecutions, setUnwrapJson, suppressPathNotFound, toString, unwrap, unwrapJson

Methods inherited from class com.adaptris.core.ServiceImp

changeState, close, continueOnFailure, createName, createQualifier, getContinueOnFail, getIsTrackingEndpoint, getUniqueId, init, isBranching, isTrackingEndpoint, requestClose, requestInit, requestStart, requestStop, retrieveComponentState, setContinueOnFail, setIsTrackingEndpoint, setUniqueId, start, stop

Methods inherited from class java.lang.Object

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

Constructor Detail

JsonPathStreamingService

public JsonPathStreamingService(DataInputParameter<java.io.InputStream> source,
                                Execution... executions)

JsonPathStreamingService

public JsonPathStreamingService(DataInputParameter<java.io.InputStream> source,
                                java.util.List<Execution> executions)

JsonPathStreamingService

public JsonPathStreamingService()

Method Detail

doService

public void doService(AdaptrisMessage message)
               throws ServiceException

.

Throws:

ServiceException

prepare

public void prepare()

getSource

@NonNull
public @NonNull DataInputParameter<java.io.InputStream> getSource()

The source for executing the jsonpath against.

setSource

public void setSource(@NonNull
                      @NonNull DataInputParameter<java.io.InputStream> source)

The source for executing the jsonpath against.

getSurfer

@NonNull
public @NonNull JsonPathStreamingService.Surfer getSurfer()

The JSON surfer implementation to use.

setSurfer

public void setSurfer(@NonNull
                      @NonNull JsonPathStreamingService.Surfer surfer)

The JSON surfer implementation to use.