com.github.tddts.jet.util.Util.java Source code

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Here is the source code for com.github.tddts.jet.util.Util.java

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/*
 * Copyright 2018 Tigran Dadaiants
 *
 * 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.github.tddts.jet.util;

import com.github.tddts.jet.exception.ApplicationException;
import com.github.tddts.jet.exception.FileLoadingException;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.Properties;

/**
 * Class providing various utility methods.
 *
 * @author Tigran_Dadaiants dtkcommon@gmail.com
 */
public class Util {

    /**
     * Load content of given resource as String.
     *
     * @param resourceName path to resource
     * @return file content as String
     * @throws FileLoadingException in case of any errors
     */
    public static String loadContent(String resourceName) throws FileLoadingException {
        try (InputStream inputStream = Util.class.getResourceAsStream(resourceName)) {
            if (inputStream == null) {
                throw new FileLoadingException("Not found: " + resourceName);
            }
            return new String(IOUtils.toByteArray(inputStream), StandardCharsets.UTF_8);
        } catch (Exception e) {
            throw new FileLoadingException(e);
        }
    }

    /**
     * Sleep for given timeout.
     * Simple wrap for {@link Thread#sleep(long)}
     *
     * @param timeout timeout
     */
    public static void sleepForTimeout(long timeout) {
        try {
            Thread.sleep(timeout);
        } catch (InterruptedException e) {
            throw new ApplicationException(e);
        }
    }

    /**
     * Save given property to given propeorty file.
     *
     * @param fileName property file path
     * @param key      property key
     * @param value    property value
     */
    public static void saveProperty(String fileName, String key, String value) {
        try {
            File file = new File(fileName);
            if (!file.exists())
                file.createNewFile();
            Properties properties = new Properties();

            try (InputStream in = FileUtils.openInputStream(file)) {
                properties.load(in);
            }

            properties.setProperty(key, value);

            try (OutputStream out = FileUtils.openOutputStream(file)) {
                properties.store(out, "");
            }

        } catch (IOException e) {
            throw new ApplicationException(e);
        }
    }

    /**
     * Load property with given key from given property file.
     *
     * @param fileName property file path
     * @param key      property key
     * @return property value
     */
    public static String loadProperty(String fileName, String key) {
        try {
            File file = new File(fileName);

            if (!file.exists())
                return null;

            Properties properties = new Properties();

            try (InputStream in = FileUtils.openInputStream(file)) {
                properties.load(in);
            }

            return properties.getProperty(key);

        } catch (IOException e) {
            throw new ApplicationException(e);
        }
    }

    /**
     * Get URL of a classpath resource
     *
     * @param resourceName name of a resource
     * @return resource URL
     */
    public static URL getClasspathResourceURL(String resourceName) {
        return Thread.currentThread().getContextClassLoader().getResource(resourceName);
    }

    /**
     * Round a value to given precision.
     *
     * @param value     value
     * @param precision precision
     * @return rounded value
     */
    public static double round(double value, int precision) {
        int scale = (int) Math.pow(10, precision);
        return (double) Math.round(value * scale) / scale;
    }

    /**
     * Cut a value to given number of decimals.
     *
     * @param val      number
     * @param decimals decimals
     * @return rounded value
     */
    public static double roundDown(double val, int decimals) {
        double pow = Math.pow(10, decimals);
        return Math.floor(val * pow) / pow;
    }

}