MonitoringRequest.java

package org.springframework.roo.file.monitor;

import java.io.File;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;

import org.apache.commons.lang3.Validate;
import org.springframework.roo.file.monitor.event.FileOperation;

/**
 * Represents a request to monitor a particular file system location.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public abstract class MonitoringRequest {

  /**
   * Factory method for monitoring the following operations upon the given
   * file or directory:
   * <ul>
   * <li>{@link FileOperation#CREATED}</li>
   * <li>{@link FileOperation#RENAMED}</li>
   * <li>{@link FileOperation#UPDATED}</li>
   * <li>{@link FileOperation#DELETED}</li>
   * </ul>
   * 
   * @param resource the resource to monitor; <code>null</code> means the
   *            current directory
   * @return a non-<code>null</code> monitoring request
   */
  public static MonitoringRequest getInitialMonitoringRequest(String resource) {
    if (resource == null) {
      resource = ".";
    }
    final MonitoringRequestEditor mre = new MonitoringRequestEditor();
    mre.setAsText(resource + ",CRUD");
    return mre.getValue();
  }

  /**
   * Factory method for monitoring the following operations upon the given
   * directory and its sub-tree:
   * <ul>
   * <li>{@link FileOperation#CREATED}</li>
   * <li>{@link FileOperation#RENAMED}</li>
   * <li>{@link FileOperation#UPDATED}</li>
   * <li>{@link FileOperation#DELETED}</li>
   * </ul>
   * 
   * @param directory the directory to monitor; <code>null</code> means the
   *            current directory
   * @return a non-<code>null</code> monitoring request
   */
  public static MonitoringRequest getInitialSubTreeMonitoringRequest(String directory) {
    if (directory == null) {
      directory = ".";
    }
    final MonitoringRequestEditor mre = new MonitoringRequestEditor();
    mre.setAsText(directory + ",CRUD,**");
    return mre.getValue();
  }

  private final Collection<FileOperation> notifyOn;
  private final File resource;

  /**
   * Constructor
   * 
   * @param resource the file to monitor (required)
   * @param notifyOn the file operations to notify upon (can't be empty)
   */
  protected MonitoringRequest(final File resource, final Collection<FileOperation> notifyOn) {
    Validate.notNull(resource, "Resource to monitor is required");
    Validate.notEmpty(notifyOn, "At least one FileOperation to monitor must be specified");
    this.notifyOn = new HashSet<FileOperation>(notifyOn);
    this.resource = resource;
  }

  /**
   * @return the file to be monitored (never null)
   */
  public File getFile() {
    return resource;
  }

  /**
   * Returns the operations to be monitored
   * 
   * @return an unmodifiable collection containing one or more elements
   */
  public Collection<FileOperation> getNotifyOn() {
    return Collections.unmodifiableCollection(notifyOn);
  }
}