org.apache.crunch.test.TemporaryPath.java Source code

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Here is the source code for org.apache.crunch.test.TemporaryPath.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.crunch.test;

import java.io.File;
import java.io.IOException;
import java.util.Set;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.junit.rules.ExternalResource;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

import com.google.common.collect.ImmutableSet;
import com.google.common.io.Files;
import com.google.common.io.Resources;

/**
 * Creates a temporary directory for a test case and destroys it afterwards.
 *
 * This provides a temporary directory like JUnit's {@link TemporaryFolder} but
 * geared towards Hadoop applications. Unlike {@link TemporaryFolder}, it
 * doesn't create any files or directories except for the root directory itself.
 *
 * Also, {@link #getDefaultConfiguration()} provides you with a configuration that
 * overrides path properties with temporary directories. You have to specify these
 * properties via the constructor.
 */
public final class TemporaryPath extends ExternalResource {
    private final TemporaryFolder tmp = new TemporaryFolder();
    private final Set<String> confKeys;

    /**
     * Construct {@code TemporaryPath}.
     * @param confKeys {@link Configuration} keys containing directories to override
     */
    public TemporaryPath(String... confKeys) {
        if (confKeys != null) {
            this.confKeys = ImmutableSet.copyOf(confKeys);
        } else {
            this.confKeys = ImmutableSet.of();
        }
    }

    public void create() throws Throwable {
        tmp.create();
    }

    public void delete() {
        tmp.delete();
    }

    @Override
    public Statement apply(Statement base, Description description) {
        return tmp.apply(base, description);
    }

    /**
     * Get the root directory which will be deleted automatically.
     */
    public File getRootFile() {
        return tmp.getRoot();
    }

    /**
     * Get the root directory as a {@link Path}.
     */
    public Path getRootPath() {
        return toPath(tmp.getRoot());
    }

    /**
     * Get the root directory as an absolute file name.
     */
    public String getRootFileName() {
        return tmp.getRoot().getAbsolutePath();
    }

    /**
     * Get a {@link File} below the temporary directory.
     */
    public File getFile(String fileName) {
        return new File(getRootFile(), fileName);
    }

    /**
     * Get a {@link Path} below the temporary directory.
     */
    public Path getPath(String fileName) {
        return toPath(getFile(fileName));
    }

    /**
     * Get an absolute file name below the temporary directory.
     */
    public String getFileName(String fileName) {
        return getFile(fileName).getAbsolutePath();
    }

    /**
     * Copy a classpath resource to {@link File}.
     */
    public File copyResourceFile(String resourceName) throws IOException {
        String baseName = new File(resourceName).getName();
        File dest = new File(tmp.getRoot(), baseName);
        copy(resourceName, dest);
        return dest;
    }

    /**
     * Copy a classpath resource to a {@link Path}.
     */
    public Path copyResourcePath(String resourceName) throws IOException {
        return toPath(copyResourceFile(resourceName));
    }

    /**
     * Copy a classpath resource returning its absolute file name.
     */
    public String copyResourceFileName(String resourceName) throws IOException {
        return copyResourceFile(resourceName).getAbsolutePath();
    }

    private static void copy(String resourceName, File dest) throws IOException {
        Resources.asByteSource(Resources.getResource(resourceName)).copyTo(Files.asByteSink(dest));
    }

    private static Path toPath(File file) {
        return new Path(file.getAbsolutePath());
    }

    public Configuration getDefaultConfiguration() {
        return overridePathProperties(new Configuration());
    }

    /**
     * Set all keys specified in the constructor to temporary directories.
     */
    public Configuration overridePathProperties(Configuration config) {
        for (String name : confKeys) {
            config.set(name, getFileName("tmp-" + name));
        }
        return config;
    }
}