com.github.jlgrock.javascriptframework.mavenutils.io.ResourceIO Maven / Gradle / Ivy

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package com.github.jlgrock.javascriptframework.mavenutils.io;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipInputStream;

import org.apache.log4j.Logger;

/**
 * A general usage class for accessing and manipulating jar resources.
 */
public final class ResourceIO {

	/**
	 * private constructor for util classes.
	 */
	private ResourceIO() {
	}

	/**
	 * The Logger.
	 */
	private static Logger logger = Logger.getLogger(ResourceIO.class);

	/**
	 * Get an input stream for a resource file within the jar.
	 * 
	 * @param resourceLocation
	 *            the path in jndi to the resource
	 * @return the InputStream of that file
	 * @throws IOException
	 *             If the resource cannot be found or there was a problem
	 *             reading the file
	 */
	public static InputStream getResourceAsStream(final String resourceLocation)
			throws IOException {
		ClassLoader cl = Thread.currentThread().getContextClassLoader();
		if (cl.getResource(resourceLocation) == null) {
			throw new IOException("Resource at location \"" + resourceLocation
					+ "\" doesn't exist");
		}
		InputStream is = new BufferedInputStream(
				cl.getResourceAsStream(resourceLocation));
		return is;
	}

	/**
	 * Get a zip input stream for a resource file within the jar.
	 * 
	 * @param resourceLocation
	 *            the path in jndi to the resource
	 * @return the ZipInputStream of that file
	 * @throws IOException
	 *             If the resource cannot be found or there was a problem
	 *             reading the file
	 */
	public static ZipInputStream getResourceAsZipStream(
			final String resourceLocation) throws IOException {
		if (resourceLocation == null) {
			throw new IOException("resourceLocation cannot be null");
		}
		return new ZipInputStream(getResourceAsStream(resourceLocation));
	}

	/**
	 * Copy any resource to an output location.
	 * 
	 * @param pathToResource
	 *            the path in jndi to the resource
	 * @param outputLocation
	 *            the location to copy the resource to
	 * @throws IOException
	 *             if there is a problem copying the resource
	 */
	public static void copyResource(final String pathToResource,
			final File outputLocation) throws IOException {
		if (pathToResource == null) {
			throw new IOException("resourceStream cannot be null");
		}
		if (outputLocation == null) {
			throw new IOException("outputLocation cannot be null");
		}

		logger.debug("copying resource from resource \"" + pathToResource
				+ "\" to \"" + outputLocation.getAbsoluteFile() + "\".");
		try {
			InputStream resourceStream = ResourceIO
					.getResourceAsStream(pathToResource);
			DirectoryIO.createDir(outputLocation.getParentFile());
			FileIO.copyStream(resourceStream, new FileOutputStream(
					outputLocation));
		} catch (IOException ioe) {
			logger.error("There was a problem copying the resource from \""
					+ pathToResource + "\" to location \""
					+ outputLocation.getAbsolutePath() + "\"");
			throw ioe;
		}
	}
	
}