getPropertyFunctionExtension.java
/*
* Copyright (c) 2016, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. licenses this file to you under the Apache License,
* Version 2.0 (the "License"); you may not use this file except
* in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.wso2.extension.siddhi.execution.json;
import org.json.JSONException;
import org.json.JSONObject;
import org.wso2.siddhi.core.config.ExecutionPlanContext;
import org.wso2.siddhi.core.exception.ExecutionPlanRuntimeException;
import org.wso2.siddhi.core.executor.ExpressionExecutor;
import org.wso2.siddhi.core.executor.function.FunctionExecutor;
import org.wso2.siddhi.query.api.definition.Attribute;
import org.wso2.siddhi.query.api.exception.ExecutionPlanValidationException;
/**
* getProperty(json , propertyName)
* Returns the vale of the property from the given json json
* Accept Type(s): (STRING, STRING)
* Return Type(s): (STRING|INT|DOUBLE|FLOAT|OBJECT)
*/
public class getPropertyFunctionExtension extends FunctionExecutor {
Attribute.Type returnType = Attribute.Type.STRING;
@Override
protected void init(ExpressionExecutor[] attributeExpressionExecutors,
ExecutionPlanContext executionPlanContext) {
if (attributeExpressionExecutors.length != 2) {
throw new ExecutionPlanValidationException(
"Invalid no of arguments passed to json:getProperty() function," + " required 2, but found "
+ attributeExpressionExecutors.length);
}
if (attributeExpressionExecutors[0].getReturnType() != Attribute.Type.STRING) {
throw new ExecutionPlanValidationException(
"Invalid parameter type found for the first argument of json:getProperty() function, " + "required "
+ Attribute.Type.STRING + ", but found " + attributeExpressionExecutors[0].getReturnType()
.toString());
}
if (attributeExpressionExecutors[1].getReturnType() != Attribute.Type.STRING) {
throw new ExecutionPlanValidationException(
"Invalid parameter type found for the second argument of json:getProperty() function, " + "required "
+ Attribute.Type.STRING + ", but found " + attributeExpressionExecutors[1].getReturnType()
.toString());
}
}
@Override
protected Object execute(Object[] data) {
if (data[0] == null) {
throw new ExecutionPlanRuntimeException("Invalid input given to json:getProperty() function. First argument cannot be null");
}
if (data[1] == null) {
throw new ExecutionPlanRuntimeException("Invalid input given to json:getProperty() function. Second argument cannot be null");
}
String jsonString = (String) data[0];
String property = (String) data[1];
JSONObject jsonObject = null;
try {
jsonObject = new JSONObject(jsonString);
return jsonObject.get(property).toString();
} catch (JSONException e) {
throw new ExecutionPlanRuntimeException("Cannot parse JSON String in json:getPeroperty() function. " + e);
}
}
@Override
protected Object execute(Object data) {
return null; //Since the getProperty function takes in 2 parameters, this method does not get called. Hence,not implemented.
}
@Override
public void start() {
//Nothing to start
}
@Override
public void stop() {
//Nothing to stop
}
@Override
public Attribute.Type getReturnType() {
return returnType;
}
@Override
public Object[] currentState() {
return null; //No need to maintain a state.
}
@Override
public void restoreState(Object[] state) {
//Since there's no need to maintain a state, nothing needs to be done here.
}
}