com.dkfqs.tools.json

Class SimpleJsonValueExtractor

java.lang.Object

com.dkfqs.tools.json.SimpleJsonValueExtractor

public class SimpleJsonValueExtractor
extends java.lang.Object

Extract simple single Json values from Json data by applying simple Json queries.

Programming Example:

String jsonSource = "{\"testArray\":[1,2,3, {\"A\":5,\"B\":7},\"X\"], \"tail\":9}";

SimpleJsonValueExtractor jsonValueExtractor = new SimpleJsonValueExtractor(jsonSource);
if (jsonValueExtractor.select("testArray.[3].A")) {
    JsonValue queryResult = jsonValueExtractor.getQueryResult();
    if (queryResult == null) {
        System.out.println("Query Result = Json null value");
    }
    else {
        System.out.println("Query Result = " + queryResult.toString());     // 5
    }
}
else {
    System.out.println("[No match found]");
}

Constructor Summary

Constructors

Constructor and Description
SimpleJsonValueExtractor(java.io.Reader jsonReader) Create a new instance from a Json Reader.
SimpleJsonValueExtractor(java.lang.String jsonSource) Create a new instance from a Json String.

Method Summary

Modifier and Type	Method and Description
JsonValue	getQueryResult() Get the extracted simple value (String, long, boolean or null).
static java.lang.String	JsonValueToString(JsonValue jsonValue) Convert a Json value of any datatype to a string.
boolean	select(java.lang.String simpleQuery) Select a simple Json value (String, long, boolean or null).

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleJsonValueExtractor

public SimpleJsonValueExtractor(java.lang.String jsonSource)

Create a new instance from a Json String.

Parameters:

jsonSource - a String containing the Json data

SimpleJsonValueExtractor

public SimpleJsonValueExtractor(java.io.Reader jsonReader)
                         throws java.io.IOException

Create a new instance from a Json Reader.

Parameters:

jsonReader - a Reader for the Json data

Throws:

java.io.IOException - if somewhat fails.

Method Detail

select

public boolean select(java.lang.String simpleQuery)

Select a simple Json value (String, long, boolean or null).

Parameters:

simpleQuery - the simple query. Examples: "[0].datapoints.[2].[1]", "customers.person.name"

Returns:

true if the query was successful

Throws:

java.lang.IllegalArgumentException - if the root of the Json data is not an Object or Array

getQueryResult

public JsonValue getQueryResult()

Get the extracted simple value (String, long, boolean or null).

Returns:

the extracted simple value, or null for Json null value

Throws:

java.lang.RuntimeException - if the query was not successful

JsonValueToString

public static java.lang.String JsonValueToString(JsonValue jsonValue)

Convert a Json value of any datatype to a string.

Parameters:

jsonValue - the Json value

Returns:

the string of the Json value