UndoableMonitoringRequest.java

package org.springframework.roo.project;

import org.apache.commons.lang3.Validate;
import org.springframework.roo.file.monitor.FileMonitorService;
import org.springframework.roo.file.monitor.MonitoringRequest;
import org.springframework.roo.file.undo.UndoManager;
import org.springframework.roo.file.undo.UndoableOperation;

/**
 * Allows {@link org.springframework.roo.file.monitor.MonitoringRequest}s to be
 * applied as {@link org.springframework.roo.file.undo.UndoableOperation}s.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public class UndoableMonitoringRequest implements UndoableOperation {

  private final boolean add;
  private final FileMonitorService fileMonitorService;
  private final MonitoringRequest monitoringRequest;
  private boolean resetRequired;

  public UndoableMonitoringRequest(final UndoManager undoManager,
      final FileMonitorService fileMonitorService, final MonitoringRequest monitoringRequest,
      final boolean add) {
    Validate.notNull(undoManager, "Undo manager required");
    Validate.notNull(fileMonitorService, "File monitor service required");
    Validate.notNull(monitoringRequest, "Request required");
    this.fileMonitorService = fileMonitorService;
    this.monitoringRequest = monitoringRequest;
    this.add = add;

    if (add) {
      resetRequired = fileMonitorService.add(monitoringRequest);
    } else {
      resetRequired = fileMonitorService.remove(monitoringRequest);
    }

    undoManager.add(this);
  }

  public void reset() {}

  public boolean undo() {
    if (!resetRequired) {
      return true;
    }
    try {
      if (add) {
        fileMonitorService.remove(monitoringRequest);
      } else {
        fileMonitorService.add(monitoringRequest);
      }
      return true;
    } catch (final RuntimeException e) {
      return false;
    }
  }
}