AbstractShellStatusPublisher.java

package org.springframework.roo.shell.event;

import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

import org.apache.commons.lang3.Validate;
import org.springframework.roo.shell.ParseResult;
import org.springframework.roo.shell.event.ShellStatus.Status;

/**
 * Provides a convenience superclass for those shells wishing to publish status
 * messages.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public abstract class AbstractShellStatusPublisher implements ShellStatusProvider {

  protected Set<ShellStatusListener> shellStatusListeners =
      new CopyOnWriteArraySet<ShellStatusListener>();
  protected ShellStatus shellStatus = new ShellStatus(Status.STARTING);

  public final void addShellStatusListener(final ShellStatusListener shellStatusListener) {
    Validate.notNull(shellStatusListener, "Status listener required");
    synchronized (shellStatus) {
      shellStatusListeners.add(shellStatusListener);
    }
  }

  public final ShellStatus getShellStatus() {
    synchronized (shellStatus) {
      return shellStatus;
    }
  }

  public final void removeShellStatusListener(final ShellStatusListener shellStatusListener) {
    Validate.notNull(shellStatusListener, "Status listener required");
    synchronized (shellStatus) {
      shellStatusListeners.remove(shellStatusListener);
    }
  }

  protected void setShellStatus(final Status shellStatus) {
    setShellStatus(shellStatus, null, null);
  }

  protected void setShellStatus(final Status shellStatus, final String msg,
      final ParseResult parseResult) {
    Validate.notNull(shellStatus, "Shell status required");

    synchronized (this.shellStatus) {
      ShellStatus st;
      if (msg == null || msg.length() == 0) {
        st = new ShellStatus(shellStatus);
      } else {
        st = new ShellStatus(shellStatus, msg, parseResult);
      }

      if (this.shellStatus.equals(st)) {
        return;
      }

      for (final ShellStatusListener listener : shellStatusListeners) {
        listener.onShellStatusChange(this.shellStatus, st);
      }
      this.shellStatus = st;
    }
  }
}