com.consol.citrus.functions.core.RandomEnumValueFunction Maven / Gradle / Ivy

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/*
 * Copyright 2006-2010 the original author or authors.
 *
 * Licensed 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 com.consol.citrus.functions.core;

import com.consol.citrus.context.TestContext;
import com.consol.citrus.exceptions.InvalidFunctionUsageException;
import com.consol.citrus.functions.Function;

import java.util.List;
import java.util.Random;

/**
 * Function to choose one random value from a list of strings. The enumeration values to choose from
 * can either be specified as parameters or in the {@link RandomEnumValueFunction#values} property of 
 * an instance of this class. These two possibilities can only be used exclusively - either empty values
 * property and non-empty parameters or empty parameters and non-empty values property.
 * Example custom function definition and the corresponding usage in a test:
 * 
 * 
 *  * <bean id="myCustomFunctionLibrary" class="com.consol.citrus.functions.FunctionLibrary">
 *  <property name="name" value="myCustomFunctionLibrary" />
 *  <property name="prefix" value="custom:" />
 *  <property name="members">
 *    <map>
 *      <entry key="randomHttpStatusCode">
 *        <bean class="com.consol.citrus.functions.core.RandomEnumValueFunction">
 *          <property name="values">
 *            <list>
 *              <value>200</value>
 *              <value>500</value>
 *              <value>401</value>
 *            </list>
 *          </property>
 *        </bean>
 *      </entry>
 *    </map>
 *  </property>
 * </bean>
 * 
 * 
 * and the corresponding usage which sets the httpStatusCode to one of the configured values - 200, 500 or 401:
 * 
 *  * <variable name="httpStatusCode" value="custom:randomHttpStatusCode()" />
 * 
 * 
 * The other usage possibility is to choose a random value from a list of values given as argument 
 * like this which achieves the same result as the previously shown custom function:
 * 
 *  * <variable name="httpStatusCode" value="citrus:randomEnumValue('200', '401', '500')" />
 * 
 * 
 * You should choose which one of the two flavours to use based on the number of times you use this function - if you need it in
 * only one special case you may go with specifying the list as arguments otherwise you should define a custom function and reuse it. 
 * 
 * @author Dimo Velev ([email protected])
 */
public class RandomEnumValueFunction implements Function {
	private Random random = new Random(System.currentTimeMillis());
	private List values = null;
	
	/**
	 * @see Function#execute(java.util.List, com.consol.citrus.context.TestContext)
	 */
	public String execute(List params, TestContext context) {
		if (values == null) {
			return randomValue(params);
		} else {
			if (!params.isEmpty()) {
				throw new InvalidFunctionUsageException("The enumeration values have already been set");
			}
			return randomValue(values);
		}
	}

	/**
	 * Pseudo-randomly choose one of the supplied values and return it.
	 * 
	 * @param values
	 * @return
	 * @throws IllegalArgumentException if the values supplied are null or an empty list.
	 */
	protected String randomValue(List values) {
		if (values == null || values.isEmpty()) {
			throw new InvalidFunctionUsageException("No values to choose from");
		}
		
		final int idx = random.nextInt(values.size());
		
		return values.get(idx);
	}

	public List getValues() {
		return values;
	}

	public void setValues(List values) {
		this.values = values;
	}
}