org.springframework.batch.item.util.FileUtils.java Source code

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Here is the source code for org.springframework.batch.item.util.FileUtils.java

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/*
 * Copyright 2006-2007 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
 *
 *      https://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.springframework.batch.item.util;

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

import org.springframework.batch.item.ItemStreamException;
import org.springframework.util.Assert;

/**
 * Utility methods for files used in batch processing.
 * 
 * @author Peter Zozom
 */
public final class FileUtils {

    // forbids instantiation
    private FileUtils() {
    }

    /**
     * Set up output file for batch processing. This method implements common logic for handling output files when
     * starting or restarting file I/O. When starting output file processing, creates/overwrites new file. When
     * restarting output file processing, checks whether file is writable.
     * 
     * @param file file to be set up
     * @param restarted true signals that we are restarting output file processing
     * @param append true signals input file may already exist (but doesn't have to)
     * @param overwriteOutputFile If set to true, output file will be overwritten (this flag is ignored when processing
     * is restart)
     */
    public static void setUpOutputFile(File file, boolean restarted, boolean append, boolean overwriteOutputFile) {

        Assert.notNull(file, "An output file is required");

        try {
            if (!restarted) {
                if (!append) {
                    if (file.exists()) {
                        if (!overwriteOutputFile) {
                            throw new ItemStreamException("File already exists: [" + file.getAbsolutePath() + "]");
                        }
                        if (!file.delete()) {
                            throw new IOException("Could not delete file: " + file);
                        }
                    }

                    if (file.getParent() != null) {
                        new File(file.getParent()).mkdirs();
                    }
                    if (!createNewFile(file)) {
                        throw new ItemStreamException(
                                "Output file was not created: [" + file.getAbsolutePath() + "]");
                    }
                } else {
                    if (!file.exists()) {
                        if (file.getParent() != null) {
                            new File(file.getParent()).mkdirs();
                        }
                        if (!createNewFile(file)) {
                            throw new ItemStreamException(
                                    "Output file was not created: [" + file.getAbsolutePath() + "]");
                        }
                    }
                }
            }
        } catch (IOException ioe) {
            throw new ItemStreamException("Unable to create file: [" + file.getAbsolutePath() + "]", ioe);
        }

        if (!file.canWrite()) {
            throw new ItemStreamException("File is not writable: [" + file.getAbsolutePath() + "]");
        }
    }

    /**
     * Set up output file for batch processing. This method implements common logic for handling output files when
     * starting or restarting file I/O. When starting output file processing, creates/overwrites new file. When
     * restarting output file processing, checks whether file is writable.
     *
     * @param file file to be set up
     * @param restarted true signals that we are restarting output file processing
     * @param overwriteOutputFile If set to true, output file will be overwritten (this flag is ignored when processing
     * is restart)
     *
     * @throws IllegalArgumentException when file is null
     * @throws ItemStreamException when starting output file processing, file exists and flag "overwriteOutputFile" is
     * set to false
     * @throws ItemStreamException when unable to create file or file is not writable
     *
     * @deprecated use the version with explicit append parameter instead. Here append=false is assumed.
     */
    @Deprecated
    public static void setUpOutputFile(File file, boolean restarted, boolean overwriteOutputFile) {
        setUpOutputFile(file, restarted, false, overwriteOutputFile);
    }

    /**
     * Create a new file if it doesn't already exist.
     * 
     * @param file the file to create on the filesystem
     * @return true if file was created else false.
     *
     * @throws IOException is thrown if error occurs during creation and file
     * does not exist.
     */
    public static boolean createNewFile(File file) throws IOException {

        if (file.exists()) {
            return false;
        }

        try {
            return file.createNewFile() && file.exists();
        } catch (IOException e) {
            // On some file systems you can get an exception here even though the
            // files was successfully created
            if (file.exists()) {
                return true;
            } else {
                throw e;
            }
        }

    }

}