com.partnet.automation.util.SystemPropsUtil.java Source code

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Here is the source code for com.partnet.automation.util.SystemPropsUtil.java

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/*
 * Copyright 2015 Partnet, Inc.
 *
 * 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.partnet.automation.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SystemPropsUtil {

    private static final Logger log = LoggerFactory.getLogger(SystemPropsUtil.class);

    private SystemPropsUtil() {
        // No instance creation.
    }

    /**
     * Load properties from the given configuration file name.
     * <p>
     * Given error message is displayed if file not found.
     * <p>
     * 
     * @param configFileName
     *          - File name of properties file.
     * @throws RuntimeException
     *           - If the file has a error while reading the properties file
     */
    public static void loadProperties(String configFileName) {
        Properties cmdlineProps = System.getProperties();
        Properties fileProps = new Properties();

        // load property file
        InputStream inputStream = SystemPropsUtil.class.getResourceAsStream(configFileName);
        if (inputStream == null) {
            // force use of classloader to look for properties file
            inputStream = SystemPropsUtil.class.getClassLoader().getResourceAsStream(configFileName);
            if (inputStream == null) {
                log.warn(String.format("Failed to locate and load properties file: %s", configFileName));
                return;
            }
        } else {
            log.info("Properties file ({}) exists", configFileName);
        }

        // load fileProps with config.properties
        try {
            fileProps.load(inputStream);
        } catch (IOException e) {
            throw new RuntimeException(
                    String.format("Failure occurred while reading properties file: %s", configFileName), e);
        }

        // Override any fileProp with cmdlineProps
        fileProps.putAll(cmdlineProps);
        System.setProperties(fileProps);
    }

    /**
     * Look for a required system property.
     * 
     * @param propertyName
     *          name of the property to get
     * @return value of the given property
     * @throws IllegalStateException
     *           if the property isn't defined or has an empty/blank value
     */
    public static String getRequiredProperty(final String propertyName) {
        String propertyValue = System.getProperty(propertyName);
        if (StringUtils.trimToNull(propertyValue) == null) {
            throw new IllegalStateException(String.format("Missing required property %s", propertyName));
        }
        return propertyValue;
    }

}