com.google.common.base.Files.java Source code

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Here is the source code for com.google.common.base.Files.java

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/*
 * Copyright (C) 2006 The Guava 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 com.google.common.base;

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

/**
 * All methods of this class, including Javadoc, were copied over verbatim from the Google Guava
 * libraries R9 (http://code.google.com/p/guava-libraries/).
 */
public class Files {

    /**
     * Creates any necessary but nonexistent parent directories of the specified
     * file. Note that if this operation fails it may have succeeded in creating
     * some (but not all) of the necessary parent directories.
     * 
     * @throws IOException if an I/O error occurs, or if any necessary but
     *           nonexistent parent directories of the specified file could not be
     *           created.
     * @since 4
     */
    public static void createParentDirs(File file) throws IOException {
        File parent = file.getCanonicalFile().getParentFile();
        if (parent == null) {
            /*
             * The given directory is a filesystem root. All zero of its ancestors
             * exist. This doesn't mean that the root itself exists -- consider x:\ on
             * a Windows machine without such a drive -- or even that the caller can
             * create it, but this method makes no such guarantees even for non-root
             * files.
             */
            return;
        }
        parent.mkdirs();
        if (!parent.isDirectory()) {
            throw new IOException("Unable to create parent directories of " + file);
        }
    }

    /**
     * Creates an empty file or updates the last updated timestamp on the
     * same as the unix command of the same name.
     * 
     * @param file the file to create or update
     * @throws IOException if an I/O error occurs
     */
    public static void touch(File file) throws IOException {
        if (!file.createNewFile() && !file.setLastModified(System.currentTimeMillis())) {
            throw new IOException("Unable to update modification time of " + file);
        }
    }

}