Used as Groovy Component in MuleESB Application

JsonObjectIterator.groovy

/**
 * @see <a href="http://stackoverflow.com/questions/6511880/how-to-parse-a-json-input-stream">how-to-parse-a-json-input-stream</a>
 * @see <a href="http://stackoverflow.com/questions/24835431/use-jackson-to-stream-parse-an-array-of-json-objects">use-jackson-to-stream-parse-an-array-of-json-objects</a>
 * @author BoostHungry <a href="http://stackoverflow.com/users/1110526/boosthungry">BoostHungry</a>
 * @author Ian Roberts <a href="http://stackoverflow.com/users/592139/ian-roberts">Ian Roberts</a>
 * @author leijiang
 *
 */
import static org.apache.commons.lang.StringUtils.*

import org.apache.commons.io.IOUtils
import org.slf4j.Logger
import org.slf4j.LoggerFactory

import com.fasterxml.jackson.core.JsonFactory
import com.fasterxml.jackson.core.JsonParser
import com.fasterxml.jackson.core.JsonToken
import com.fasterxml.jackson.core.type.TypeReference
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.node.ObjectNode

Logger logger = LoggerFactory.getLogger("mix.notification-api-v1.json-object-iterator")

if(!payload instanceof InputStream) {
	throw new RuntimeException("Wrong payload type returned! Should be InputStream")
}

def jsonstream = payload

interface CloseableJsonObjectIterator extends Iterator, Closeable {}
ObjectMapper mapper = new ObjectMapper()
JsonFactory factory = mapper.getFactory()
JsonParser parser

try {
	parser = factory.createParser(jsonstream)
} catch (IOException e) {
	logger.error("There was a problem setting up the JsonParser: " + e.getMessage(), e);
	throw new RuntimeException("There was a problem setting up the JsonParser: " + e.getMessage(), e);
}

try {
	// Check that the first element is the start of an array
	JsonToken arrayStartToken = parser.nextToken();
	if (arrayStartToken != JsonToken.START_ARRAY) {
		throw new IllegalStateException("The first element of the Json structure was expected to be a start array token, but it was: " + arrayStartToken);
	}
} catch (final Exception e) {
	logger.error("There was a problem initializing the first element of the Json Structure: " + e.getMessage(), e);
	throw new RuntimeException("There was a problem initializing the first element of the Json Structure: " + e.getMessage(), e);
}

def nextToken = parser.nextToken();

if (nextToken != JsonToken.START_OBJECT) {
	throw new IllegalStateException("The second token of Json structure was expected to be a start object token, but it was: " + nextToken);
}

return [
	hasNext: {
		//println("hasNext? $nextToken")
		if(nextToken != null && nextToken != JsonToken.END_ARRAY) {
			return true	
		}else {
			return false
		}
	},

	next: {
		//println("next? $nextToken")
		ObjectNode node
		
		if(nextToken == JsonToken.START_OBJECT) {
			// read everything from this START_OBJECT to the matching END_OBJECT
			// and return it as a tree model ObjectNode
			node = mapper.readTree(parser);
			
		}
		nextToken = parser.nextToken()
		//println("nextDone? $nextToken")
		return node.toString()
		 
	},
	close: {
		IOUtils.closeQuietly(is);
		parser.close()
	}

] as CloseableJsonObjectIterator