/
IsEmptyFunctionExtension.java
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/
IsEmptyFunctionExtension.java
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/*
* Copyright (c) 2019, 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 io.siddhi.extension.execution.map;
import io.siddhi.annotation.Example;
import io.siddhi.annotation.Extension;
import io.siddhi.annotation.Parameter;
import io.siddhi.annotation.ParameterOverload;
import io.siddhi.annotation.ReturnAttribute;
import io.siddhi.annotation.util.DataType;
import io.siddhi.core.config.SiddhiQueryContext;
import io.siddhi.core.exception.SiddhiAppRuntimeException;
import io.siddhi.core.executor.ExpressionExecutor;
import io.siddhi.core.executor.function.FunctionExecutor;
import io.siddhi.core.util.config.ConfigReader;
import io.siddhi.core.util.snapshot.state.State;
import io.siddhi.core.util.snapshot.state.StateFactory;
import io.siddhi.query.api.definition.Attribute;
import java.util.Map;
/**
* isEmpty(Object)
* Returns boolean true if the object is empty map, boolean false if it is not .
* Accept Type(s): (Object)
* Return Type(s): boolean
*/
@Extension(
name = "isEmpty",
namespace = "map",
description = "Function checks if the map is empty.",
parameters = {
@Parameter(name = "map",
description = "The map the need to be checked whether it's empty or not.",
type = {DataType.OBJECT},
dynamic = true
)
},
parameterOverloads = {
@ParameterOverload(parameterNames = {"map"})
},
returnAttributes =
@ReturnAttribute(
description = "Returns `true` if the map is empty and `false` if otherwise.",
type = DataType.BOOL
),
examples =
@Example(
syntax = "map:isEmpty(stockDetails)",
description = "Returns 'true' if the stockDetails map is empty else it returns `false`."
)
)
public class IsEmptyFunctionExtension extends FunctionExecutor<State> {
private Attribute.Type returnType = Attribute.Type.BOOL;
private static final long serialVersionUID = 1L;
@Override
protected StateFactory<State> init(ExpressionExecutor[] attributeExpressionExecutors,
ConfigReader configReader,
SiddhiQueryContext siddhiQueryContext) {
return null;
}
@Override
protected Object execute(Object[] data, State state) {
return null;
}
@Override
protected Boolean execute(Object data, State state) {
if (data instanceof Map) {
return ((Map) data).isEmpty();
}
throw new SiddhiAppRuntimeException("First attribute value must be of type java.util.Map, but found '" +
data.getClass().getCanonicalName() + "'.");
}
@Override
public Attribute.Type getReturnType() {
return returnType;
}
}