oz.hadoop.yarn.api.utils.ConfigUtils.java Source code

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Here is the source code for oz.hadoop.yarn.api.utils.ConfigUtils.java

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/*
 * Copyright 2014 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 oz.hadoop.yarn.api.utils;

import java.io.File;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

import org.apache.hadoop.conf.Configuration;
import org.springframework.util.Assert;

/**
 * Utilities to manipulate {@link Configuration} object to be used for
 * bootstrapping the application. 
 * 
 * @author Oleg Zhurakousky
 * 
 */
public class ConfigUtils {

    private ConfigUtils() {
    }

    /**
     * Will dynamically add configuration directory to the classpath.
     * 
     * @param configurationDirectoryPath
     */
    public static void addToClasspath(File configurationDirectoryPath) {
        Assert.notNull(configurationDirectoryPath, "'configurationDirectoryPath' must not be null");
        Assert.isTrue(configurationDirectoryPath.exists(), "'configurationDirectoryPath' must exist");
        Assert.isTrue(configurationDirectoryPath.isDirectory(), "'configurationDirectoryPath' must be a directory");

        URL configUrl = null;
        try {
            configUrl = new URL("file:" + configurationDirectoryPath.getAbsolutePath() + "/");
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to construct URL for " + configurationDirectoryPath, e);
        }
        URLClassLoader cl = (URLClassLoader) ClassLoader.getSystemClassLoader();
        Method addUrlMethod = ReflectionUtils.getMethodAndMakeAccessible(URLClassLoader.class, "addURL", URL.class);
        try {
            addUrlMethod.invoke(cl, configUrl);
        } catch (Exception e) {
            throw new IllegalStateException("Failed to add URL: " + configUrl + " to the classpath", e);
        }
    }
}