contrail.util.FileHelper.java Source code

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Here is the source code for contrail.util.FileHelper.java

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/**
 * Copyright 2012 Google Inc. All Rights Reserved.
 *
 * 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.
 */
// Author: Jeremy Lewi (jeremy@lewi.us)

package contrail.util;

import static org.junit.Assert.fail;

import java.io.File;
import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

/**
 * Some routines for working with files.
 *
 * The class is named FileHelper as opposed to FileUtil to avoid confusion
 * with the FileUtil class that Apache provides for hadoop.
 */
public class FileHelper {
    /**
     * Create a local temporary directory.
     * @return
     */
    static public File createLocalTempDir() {
        // TODO(jlewi): Is there a java function we could use?
        File temp = null;
        try {
            temp = File.createTempFile("temp", Long.toString(System.nanoTime()));
        } catch (IOException exception) {
            fail("Could not create temporary file. Exception:" + exception.getMessage());
        }
        if (!(temp.delete())) {
            throw new RuntimeException("Could not delete temp file: " + temp.getAbsolutePath());
        }

        if (!(temp.mkdir())) {
            throw new RuntimeException("Could not create temp directory: " + temp.getAbsolutePath());
        }
        return temp;
    }

    /**
     * Function moves the contents of old_path into new_path. This is used
     * to save the final graph.
     * @param oldPath
     * @param newPath
     */
    static public void moveDirectoryContents(Configuration conf, String oldPath, String newPath) {
        // We can't invoke rename directly on old path because it ends up
        // making old_path a subdirectory of new_path.
        FileSystem fs = null;
        try {
            fs = FileSystem.get(conf);
        } catch (IOException e) {
            throw new RuntimeException("Can't get filesystem: " + e.getMessage());
        }
        try {
            Path oldPathObject = new Path(oldPath);
            for (FileStatus status : fs.listStatus(oldPathObject)) {
                Path oldFile = status.getPath();
                Path newFile = new Path(newPath, oldFile.getName());
                fs.rename(oldFile, newFile);
            }
        } catch (IOException e) {
            throw new RuntimeException("Problem moving the files: " + e.getMessage());
        }
    }
}