UpdateFile.java

package org.springframework.roo.file.undo;

import java.io.File;
import java.io.IOException;
import java.util.logging.Logger;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.Validate;
import org.springframework.roo.support.logging.HandlerUtils;

/**
 * {@link UndoableOperation} to update a file.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public class UpdateFile implements UndoableOperation {

  private static final Logger LOGGER = HandlerUtils.getLogger(UpdateFile.class);

  private final File actual;
  private final File backup;
  private final FilenameResolver filenameResolver;

  /**
   * Constructor
   * 
   * @param undoManager cannot be <code>null</code>
   * @param filenameResolver cannot be <code>null</code>
   * @param actual the file to be updated; must be an existing file (not a
   *            directory)
   */
  public UpdateFile(final UndoManager undoManager, final FilenameResolver filenameResolver,
      final File actual) {
    Validate.notNull(undoManager, "Undo manager required");
    Validate.notNull(actual, "File required");
    Validate.isTrue(actual.exists(), "File '%s' must exist", actual);
    Validate.isTrue(actual.isFile(), "Path '%s' must be a file (not a directory)", actual);
    Validate.notNull(filenameResolver, "Filename resolver required");
    this.filenameResolver = filenameResolver;
    try {
      backup = File.createTempFile("UpdateFile", "tmp");
      FileUtils.copyFile(actual, backup);
    } catch (final IOException ioe) {
      throw new IllegalStateException("Unable to make a backup of file '" + actual + "'", ioe);
    }
    this.actual = actual;
    undoManager.add(this);
  }

  public void reset() {
    // Fix for ROO-1555
    try {
      if (backup.delete()) {
        LOGGER.finest("Reset manage " + filenameResolver.getMeaningfulName(backup));
      } else {
        backup.deleteOnExit();
        LOGGER.fine("Reset failed " + filenameResolver.getMeaningfulName(backup));
      }
    } catch (final Throwable e) {
      backup.deleteOnExit();
      LOGGER.fine("Reset failed " + filenameResolver.getMeaningfulName(backup));
    }
  }

  public boolean undo() {
    try {
      FileUtils.copyFile(backup, actual);
      LOGGER.fine("Undo manage " + filenameResolver.getMeaningfulName(actual));
      return true;
    } catch (final IOException ioe) {
      LOGGER.fine("Undo failed " + filenameResolver.getMeaningfulName(actual));
      return false;
    }
  }
}