blob: a89940e08db982b964793366c6d4d5989f647e47 [file] [log] [blame]
/*
* $Header: /cvshome/build/org.osgi.service.startlevel/src/org/osgi/service/startlevel/StartLevel.java,v 1.9 2005/08/05 03:22:04 hargrave Exp $
*
* Copyright (c) OSGi Alliance (2002, 2005). All Rights Reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this
* distribution, and is available at http://www.eclipse.org/legal/epl-v10.html.
*/
package org.osgi.service.startlevel;
import org.osgi.framework.Bundle;
/**
* The StartLevel service allows management agents to manage a start level
* assigned to each bundle and the active start level of the Framework. There is
* at most one StartLevel service present in the OSGi environment.
*
* <p>
* A start level is defined to be a state of execution in which the Framework
* exists. StartLevel values are defined as unsigned integers with 0 (zero)
* being the state where the Framework is not launched. Progressively higher
* integral values represent progressively higher start levels. e.g. 2 is a
* higher start level than 1.
* <p>
* Access to the StartLevel service is protected by corresponding
* <code>ServicePermission</code>. In addition <code>AdminPermission</code>
* is required to actually modify start level information.
* <p>
* Start Level support in the Framework includes the ability to control the
* beginning start level of the Framework, to modify the active start level of
* the Framework and to assign a specific start level to a bundle. How the
* beginning start level of a Framework is specified is implementation
* dependent. It may be a command line argument when invoking the Framework
* implementation.
* <p>
* When the Framework is first started it must be at start level zero. In this
* state, no bundles are running. This is the initial state of the Framework
* before it is launched.
*
* When the Framework is launched, the Framework will enter start level one and
* all bundles which are assigned to start level one and are persistently marked
* to be started are started as described in the <code>Bundle.start</code>
* method. Within a start level, bundles are started in ascending order by
* <code>Bundle.getBundleId</code>. The Framework will continue to increase
* the start level, starting bundles at each start level, until the Framework
* has reached a beginning start level. At this point the Framework has
* completed starting bundles and will then fire a Framework event of type
* <code>FrameworkEvent.STARTED</code> to announce it has completed its
* launch.
*
* <p>
* The StartLevel service can be used by management bundles to alter the active
* start level of the framework.
*
* @version $Revision: 1.9 $
*/
public interface StartLevel {
/**
* Return the active start level value of the Framework.
*
* If the Framework is in the process of changing the start level this
* method must return the active start level if this differs from the
* requested start level.
*
* @return The active start level value of the Framework.
*/
public abstract int getStartLevel();
/**
* Modify the active start level of the Framework.
*
* <p>
* The Framework will move to the requested start level. This method will
* return immediately to the caller and the start level change will occur
* asynchronously on another thread.
*
* <p>
* If the specified start level is higher than the active start level, the
* Framework will continue to increase the start level until the Framework
* has reached the specified start level, starting bundles at each start
* level which are persistently marked to be started as described in the
* <code>Bundle.start</code> method.
*
* At each intermediate start level value on the way to and including the
* target start level, the framework must:
* <ol>
* <li>Change the active start level to the intermediate start level value.
* <li>Start bundles at the intermediate start level in ascending order by
* <code>Bundle.getBundleId</code>.
* </ol>
* When this process completes after the specified start level is reached,
* the Framework will fire a Framework event of type
* <code>FrameworkEvent.STARTLEVEL_CHANGED</code> to announce it has moved
* to the specified start level.
*
* <p>
* If the specified start level is lower than the active start level, the
* Framework will continue to decrease the start level until the Framework
* has reached the specified start level stopping bundles at each start
* level as described in the <code>Bundle.stop</code> method except that
* their persistently recorded state indicates that they must be restarted
* in the future.
*
* At each intermediate start level value on the way to and including the
* specified start level, the framework must:
* <ol>
* <li>Stop bundles at the intermediate start level in descending order by
* <code>Bundle.getBundleId</code>.
* <li>Change the active start level to the intermediate start level value.
* </ol>
* When this process completes after the specified start level is reached,
* the Framework will fire a Framework event of type
* <code>FrameworkEvent.STARTLEVEL_CHANGED</code> to announce it has moved
* to the specified start level.
*
* <p>
* If the specified start level is equal to the active start level, then no
* bundles are started or stopped, however, the Framework must fire a
* Framework event of type <code>FrameworkEvent.STARTLEVEL_CHANGED</code>
* to announce it has finished moving to the specified start level. This
* event may arrive before the this method return.
*
* @param startlevel The requested start level for the Framework.
* @throws IllegalArgumentException If the specified start level is less
* than or equal to zero.
* @throws SecurityException If the caller does not have
* <code>AdminPermission[System Bundle,STARTLEVEL]</code> and the Java runtime
* environment supports permissions.
*/
public abstract void setStartLevel(int startlevel);
/**
* Return the assigned start level value for the specified Bundle.
*
* @param bundle The target bundle.
* @return The start level value of the specified Bundle.
* @throws java.lang.IllegalArgumentException If the specified bundle has
* been uninstalled.
*/
public abstract int getBundleStartLevel(Bundle bundle);
/**
* Assign a start level value to the specified Bundle.
*
* <p>
* The specified bundle will be assigned the specified start level. The
* start level value assigned to the bundle will be persistently recorded by
* the Framework.
*
* If the new start level for the bundle is lower than or equal to the
* active start level of the Framework, the Framework will start the
* specified bundle as described in the <code>Bundle.start</code> method
* if the bundle is persistently marked to be started. The actual starting
* of this bundle must occur asynchronously.
*
* If the new start level for the bundle is higher than the active start
* level of the Framework, the Framework will stop the specified bundle as
* described in the <code>Bundle.stop</code> method except that the
* persistently recorded state for the bundle indicates that the bundle must
* be restarted in the future. The actual stopping of this bundle must occur
* asynchronously.
*
* @param bundle The target bundle.
* @param startlevel The new start level for the specified Bundle.
* @throws IllegalArgumentException If the specified bundle has been
* uninstalled or if the specified start level is less than or equal
* to zero, or the specified bundle is the system bundle.
* @throws SecurityException If the caller does not have
* <code>AdminPermission[bundle,EXECUTE]</code> and the Java runtime
* environment supports permissions.
*/
public abstract void setBundleStartLevel(Bundle bundle, int startlevel);
/**
* Return the initial start level value that is assigned to a Bundle when it
* is first installed.
*
* @return The initial start level value for Bundles.
* @see #setInitialBundleStartLevel
*/
public abstract int getInitialBundleStartLevel();
/**
* Set the initial start level value that is assigned to a Bundle when it is
* first installed.
*
* <p>
* The initial bundle start level will be set to the specified start level.
* The initial bundle start level value will be persistently recorded by the
* Framework.
*
* <p>
* When a Bundle is installed via <code>BundleContext.installBundle</code>,
* it is assigned the initial bundle start level value.
*
* <p>
* The default initial bundle start level value is 1 unless this method has
* been called to assign a different initial bundle start level value.
*
* <p>
* Thie method does not change the start level values of installed bundles.
*
* @param startlevel The initial start level for newly installed bundles.
* @throws IllegalArgumentException If the specified start level is less
* than or equal to zero.
* @throws SecurityException If the caller does not have
* <code>AdminPermission[System Bundle,STARTLEVEL]</code> and the Java runtime
* environment supports permissions.
*/
public abstract void setInitialBundleStartLevel(int startlevel);
/**
* Return the persistent state of the specified bundle.
*
* <p>
* This method returns the persistent state of a bundle. The persistent
* state of a bundle indicates whether a bundle is persistently marked to be
* started when it's start level is reached.
*
* @return <code>true</code> if the bundle is persistently marked to be
* started, <code>false</code> if the bundle is not persistently
* marked to be started.
* @throws java.lang.IllegalArgumentException If the specified bundle has
* been uninstalled.
*/
public abstract boolean isBundlePersistentlyStarted(Bundle bundle);
}