/*
 * $Header: /cvsroot/eclipse/org.eclipse.equinox.app/src/org/osgi/service/application/ApplicationDescriptor.java,v 1.7 2006/09/15 14:46:00 twatson Exp $
 * 
 * Copyright (c) OSGi Alliance (2004, 2006). All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.osgi.service.application;

import java.util.Iterator;
import java.util.Map;
import org.eclipse.equinox.internal.app.AppPersistence;
import org.osgi.framework.Constants;
import org.osgi.framework.InvalidSyntaxException;

/**
 * An OSGi service that represents an installed application and stores
 * information about it. The application descriptor can be used for instance
 * creation.
 */

public abstract class ApplicationDescriptor {
	/*
	 * NOTE: An implementor may also choose to replace this class in
	 * their distribution with a class that directly interfaces with the
	 * org.osgi.service.application implementation. This replacement class MUST NOT alter the
	 * public/protected signature of this class.
	 */

	/**
	 * The property key for the localized name of the application.
	 */
	public static final String APPLICATION_NAME = "application.name";

	/**
	 * The property key for the localized icon of the application.
	 */
	public static final String APPLICATION_ICON = "application.icon";

	/**
	 * The property key for the unique identifier (PID) of the application.
	 */
	public static final String APPLICATION_PID = Constants.SERVICE_PID;

	/**
	 * The property key for the version of the application.
	 */
	public static final String APPLICATION_VERSION = "application.version";

	/**
	 * The property key for the name of the application vendor.
	 */
	public static final String APPLICATION_VENDOR = Constants.SERVICE_VENDOR;


	/**
	 * The property key for the visibility property of the application.
	 */
	public static final String APPLICATION_VISIBLE = "application.visible";

	/**
	 * The property key for the launchable property of the application.
	 */
	public static final String APPLICATION_LAUNCHABLE = "application.launchable";

	/**
	 * The property key for the locked property of the application.
	 */
	public static final String APPLICATION_LOCKED = "application.locked";

	/**
	 * The property key for the localized description of the application.
	 */
	public static final String APPLICATION_DESCRIPTION = "application.description";

	/**
	 * The property key for the localized documentation of the application.
	 */
	public static final String APPLICATION_DOCUMENTATION = "application.documentation";

	/**
	 * The property key for the localized copyright notice of the application.
	 */
	public static final String APPLICATION_COPYRIGHT = "application.copyright";

	/**
	 * The property key for the localized license of the application.
	 */
	public static final String APPLICATION_LICENSE = "application.license";

	/**
	 * The property key for the application container of the application.
	 */
	public static final String APPLICATION_CONTAINER = "application.container";

	/**
	 * The property key for the location of the application.
	 */
	public static final String APPLICATION_LOCATION = "application.location";

	
	private final String	pid;

	private boolean[]				locked = {false};

	/**
	 * Constructs the <code>ApplicationDescriptor</code>.
	 *
	 * @param applicationId
	 *            The identifier of the application. Its value is also available
	 *            as the <code>service.pid</code> service property of this 
	 *            <code>ApplicationDescriptor</code> service. This parameter must not
	 *            be <code>null</code>.
	 * @throws NullPointerException if the specified <code>applicationId</code> is null.
	 */
	protected  ApplicationDescriptor(String applicationId) {
		if(null == applicationId ) {
			throw new NullPointerException("Application ID must not be null!");
		}
		
		this.pid = applicationId;
		locked[0] = isLocked();
	}

	/**
	 * Returns the identifier of the represented application.
	 * 
	 * @return the identifier of the represented application
	 */
	public final String getApplicationId() {
		return pid;
	}

	/**
	 * This method verifies whether the specified <code>pattern</code>
	 * matches the Distinguished Names of any of the certificate chains
	 * used to authenticate this application.
	 * <P>
	 * The <code>pattern</code> must adhere to the 
	 * syntax defined in {@link org.osgi.service.application.ApplicationAdminPermission}
	 * for signer attributes. 
	 * <p>
	 * This method is used by {@link ApplicationAdminPermission#implies(java.security.Permission)} method
	 * to match target <code>ApplicationDescriptor</code> and filter. 
	 * 
	 * @param pattern a pattern for a chain of Distinguished Names. It must not be null.
	 * @return <code>true</code> if the specified pattern matches at least
	 *   one of the certificate chains used to authenticate this application 
	 * @throws NullPointerException if the specified <code>pattern</code> is null.
     * @throws IllegalStateException if the application descriptor was
     *   unregistered
	 */	
	public abstract boolean matchDNChain( String pattern );
	
	/**
	 * Returns the properties of the application descriptor as key-value pairs.
	 * The return value contains the locale aware and unaware properties as
	 * well. The returned <code>Map</code> will include the service
	 * properties of this <code>ApplicationDescriptor</code> as well.
	 * <p>
	 * This method will call the <code>getPropertiesSpecific</code> method
	 * to enable the container implementation to insert application model and/or
	 * container implementation specific properties.
	 * <P>
	 * The returned {@link java.util.Map} will contain the standard OSGi service 
	 * properties as well
	 * (e.g. service.id, service.vendor etc.) and specialized application
	 * descriptors may offer further service properties. The returned Map contains
	 * a snapshot of the properties. It will not reflect further changes in the
	 * property values nor will the update of the Map change the corresponding
	 * service property.
	 *   
	 * @param locale
	 *            the locale string, it may be null, the value null means the
	 *            default locale. If the provided locale is the empty String 
	 *            (<code>""</code>)then raw (non-localized) values are returned.
	 * 
	 * @return copy of the service properties of this application descriptor service,
	 *         according to the specified locale. If locale is null then the
	 *         default locale's properties will be returned. (Since service
	 *         properties are always exist it cannot return null.)
	 * 
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	public final Map getProperties(String locale) {
		Map props = getPropertiesSpecific( locale );
		Boolean containerLocked = (Boolean) props.remove( APPLICATION_LOCKED );
		synchronized (locked) {
			if (containerLocked != null && containerLocked.booleanValue() != locked[0]) {
				if (locked[0])
					lockSpecific();
				else
					unlockSpecific();
			}
		}
		props.put( APPLICATION_LOCKED, new Boolean( locked[0] ) );
		return props;
	}
	
	/**
	 * Container implementations can provide application model specific
	 * and/or container implementation specific properties via this 
	 * method. 
	 * 
	 * Localizable properties must be returned localized if the provided
	 * <code>locale</code> argument is not the empty String. The value
	 * <code>null</code> indicates to use the default locale, for other
	 * values the specified locale should be used.
	 *  
	 * The returned {@link java.util.Map} must contain the standard OSGi service 
	 * properties as well
	 * (e.g. service.id, service.vendor etc.) and specialized application
	 * descriptors may offer further service properties. 
	 * The returned <code>Map</code>
	 * contains a snapshot of the properties. It will not reflect further changes in the
	 * property values nor will the update of the Map change the corresponding
	 * service property.

	 * @param locale the locale to be used for localizing the properties.
	 * If <code>null</code> the default locale should be used. If it is
	 * the empty String (<code>""</code>) then raw (non-localized) values
	 * should be returned.
	 * 
	 * @return the application model specific and/or container implementation
	 * specific properties of this application descriptor.
	 *  
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	protected abstract Map getPropertiesSpecific(String locale);

	/**
	 * Launches a new instance of an application. The <code>args</code> parameter specifies
	 * the startup parameters for the instance to be launched, it may be null.
	 * <p>
	 * The following steps are made:
	 * <UL>
	 * <LI>Check for the appropriate permission.
	 * <LI>Check the locking state of the application. If locked then return
	 * null otherwise continue.
	 * <LI>Calls the <code>launchSpecific()</code> method to create and start an application
	 * instance.
	 * <LI>Returns the <code>ApplicationHandle</code> returned by the 
	 * launchSpecific()
	 * </UL>
	 * The caller has to have ApplicationAdminPermission(applicationPID,
	 * "launch") in order to be able to perform this operation.
	 * <P>
	 * The <code>Map</code> argument of the launch method contains startup 
	 * arguments for the
	 * application. The keys used in the Map must be non-null, non-empty <code>String<code>
	 * objects. They can be standard or application
	 * specific. OSGi defines the <code>org.osgi.triggeringevent</code>
	 * key to be used to
	 * pass the triggering event to a scheduled application, however
	 * in the future it is possible that other well-known keys will be defined.
	 * To avoid unwanted clashes of keys, the following rules should be applied:
	 * <ul>
	 *   <li>The keys starting with the dash (-) character are application
	 *       specific, no well-known meaning should be associated with them.</li>
	 *   <li>Well-known keys should follow the reverse domain name based naming.
	 *       In particular, the keys standardized in OSGi should start with
	 *       <code>org.osgi.</code>.</li>
	 * </ul>
	 * <P>
	 * The method is synchonous, it return only when the application instance was
	 * successfully started or the attempt to start it failed.
	 * <P>
	 * This method never returns <code>null</code>. If launching an application fails,
	 * the appropriate exception is thrown.
	 * 
	 * @param arguments
	 *            Arguments for the newly launched application, may be null
	 * 
	 * @return the registered ApplicationHandle, which represents the newly 
	 *         launched application instance. Never returns <code>null</code>.
	 * 
	 * @throws SecurityException
	 *             if the caller doesn't have "lifecycle"
	 *             ApplicationAdminPermission for the application.
	 * @throws ApplicationException
	 *             if starting the application failed
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 * @throws IllegalArgumentException 
	 *             if the specified <code>Map</code> contains invalid keys
	 *             (null objects, empty <code>String</code> or a key that is not
	 *              <code>String</code>)
	 */
	public final ApplicationHandle launch(Map arguments)
			throws ApplicationException {
		SecurityManager sm = System.getSecurityManager();
		if (sm!= null)
			sm.checkPermission(new ApplicationAdminPermission(this, ApplicationAdminPermission.LIFECYCLE_ACTION));
		synchronized (locked) {
			if (locked[0])
				throw new ApplicationException(ApplicationException.APPLICATION_LOCKED, "Application is locked, can't launch!");
		}
		if( !isLaunchableSpecific() )
			throw new ApplicationException(ApplicationException.APPLICATION_NOT_LAUNCHABLE,
					 "Cannot launch the application!");
		checkArgs(arguments);
		try {
			return launchSpecific(arguments);
		} catch(IllegalStateException ise) {
			throw ise;
		} catch(SecurityException se) {
			throw se;
		} catch( ApplicationException ae) {
			throw ae;
		} catch(Exception t) {
			throw new ApplicationException(ApplicationException.APPLICATION_INTERNAL_ERROR, t);
		}
	}

	/**
	 * Called by launch() to create and start a new instance in an application
	 * model specific way. It also creates and registeres the application handle
	 * to represent the newly created and started instance and registeres it.
	 * The method is synchonous, it return only when the application instance was
	 * successfully started or the attempt to start it failed.
	 * <P>
	 * This method must not return <code>null</code>. If launching the application
	 * failed, and exception must be thrown.
	 * 
	 * @param arguments
	 *            the startup parameters of the new application instance, may be
	 *            null
	 * 
	 * @return the registered application model
	 *         specific application handle for the newly created and started
	 *         instance.
	 * 
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 * @throws Exception
	 *             if any problem occures.
	 */
	protected abstract ApplicationHandle launchSpecific(Map arguments)
			throws Exception;
	
	/**
	 * This method is called by launch() to verify that according to the
	 * container, the application is launchable.
	 * 
	 * @return true, if the application is launchable according to the 
	 *  container, false otherwise.
	 *  
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	protected abstract boolean isLaunchableSpecific();

	/**
	 * Schedules the application at a specified event. Schedule information
	 * should not get lost even if the framework or the device restarts so it
	 * should be stored in a persistent storage. The method registers a
	 * {@link ScheduledApplication} service in Service Registry, representing
	 * the created schedule.
	 * <p>
	 * The <code>Map</code> argument of the  method contains startup 
	 * arguments for the application. The keys used in the Map must be non-null, 
	 * non-empty <code>String<code> objects.
     * <p>
     * The created schedules have a unique identifier within the scope of this
     * <code>ApplicationDescriptor</code>. This identifier can be specified
     * in the <code>scheduleId</code> argument. If this argument is <code>null</code>,
     * the identifier is automatically generated.
     * 
	 * @param scheduleId 
	 *             the identifier of the created schedule. It can be <code>null</code>,
     *             in this case the identifier is automatically generated.
	 * @param arguments
	 *            the startup arguments for the scheduled application, may be
	 *            null
	 * @param topic
	 *            specifies the topic of the triggering event, it may contain a
	 *            trailing asterisk as wildcard, the empty string is treated as
	 *            "*", must not be null
	 * @param eventFilter
	 *            specifies and LDAP filter to filter on the properties of the
	 *            triggering event, may be null
	 * @param recurring
	 *            if the recurring parameter is false then the application will
	 *            be launched only once, when the event firstly occurs. If the
	 *            parameter is true then scheduling will take place for every
	 *            event occurrence; i.e. it is a recurring schedule
	 * 
	 * @return the registered scheduled application service
	 * 
	 * @throws NullPointerException
	 *             if the topic is <code>null</code>
	 * @throws InvalidSyntaxException 
	 * 			   if the specified <code>eventFilter</code> is not syntactically correct
	 * @throws ApplicationException
     *              if the schedule couldn't be created. The possible error
     *              codes are 
     *              <ul>
     *               <li> {@link ApplicationException#APPLICATION_DUPLICATE_SCHEDULE_ID}
     *                 if the specified <code>scheduleId</code> is already used
     *                 for this <code>ApplicationDescriptor</code>
     *               <li> {@link ApplicationException#APPLICATION_SCHEDULING_FAILED}
     *                 if the scheduling failed due to some internal reason
     *                 (e.g. persistent storage error).
     *              </ul>
	 * @throws SecurityException
	 *             if the caller doesn't have "schedule"
	 *             ApplicationAdminPermission for the application.
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 * @throws IllegalArgumentException
	 *             if the specified <code>Map</code> contains invalid keys
	 *             (null objects, empty <code>String</code> or a key that is not
	 *              <code>String</code>)
	 */
	public final ScheduledApplication schedule(String scheduleId, Map arguments, String topic,
			String eventFilter, boolean recurring) throws InvalidSyntaxException, 
            ApplicationException {
		SecurityManager sm = System.getSecurityManager();
		if (sm != null)
			sm.checkPermission(new ApplicationAdminPermission(this, ApplicationAdminPermission.SCHEDULE_ACTION));
		checkArgs(arguments);
		isLaunchableSpecific(); // checks if the ApplicationDescriptor was already unregistered
		return AppPersistence.addScheduledApp(this, scheduleId, arguments, topic, eventFilter, recurring);
	}

	/**
	 * Sets the lock state of the application. If an application is locked then
	 * launching a new instance is not possible. It does not affect the already
	 * launched instances.
	 * 
	 * @throws SecurityException
	 *             if the caller doesn't have "lock" ApplicationAdminPermission
	 *             for the application.
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	public final void lock() {
		SecurityManager sm = System.getSecurityManager();
		if (sm != null)
			sm.checkPermission(new ApplicationAdminPermission(this, ApplicationAdminPermission.LOCK_ACTION));
		synchronized (locked) {
			if (locked[0])
				return;
			locked[0] = true;
			lockSpecific();
			saveLock(true);
		}
	}
	
	/**
	 * This method is used to notify the container implementation that the
	 * corresponding application has been locked and it should update the
	 * <code>application.locked</code> service property accordingly.
     * @throws IllegalStateException
     *             if the application descriptor is unregistered
	 */
	protected abstract void lockSpecific();

	/**
	 * Unsets the lock state of the application.
	 * 
	 * @throws SecurityException
	 *             if the caller doesn't have "lock" ApplicationAdminPermission
	 *             for the application.
	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	public final void unlock() {
		SecurityManager sm = System.getSecurityManager();
		if (sm != null)
			sm.checkPermission(new ApplicationAdminPermission(this, ApplicationAdminPermission.LOCK_ACTION));
		synchronized (locked) {
			if (!locked[0])
				return;
			locked[0] = false;
			unlockSpecific();
			saveLock(false);
		}
	}
	
	/**
	 * This method is used to notify the container implementation that the
	 * corresponding application has been unlocked and it should update the
	 * <code>application.locked</code> service property accordingly.

	 * @throws IllegalStateException
	 *             if the application descriptor is unregistered
	 */
	protected abstract void unlockSpecific();

	private void saveLock(boolean locked) {
		AppPersistence.saveLock(this, locked);
	}

	private boolean isLocked() {
		return AppPersistence.isLocked(this);
	}

	private void checkArgs(Map arguments) {
		if (arguments == null)
			return;
		for (Iterator keys = arguments.keySet().iterator(); keys.hasNext();) {
			Object key = keys.next();
			if (!(key instanceof String))
				throw new IllegalArgumentException("Invalid key type: " + key == null ? "<null>" : key.getClass().getName());
			if ("".equals(key)) //$NON-NLS-1$
				throw new IllegalArgumentException("Empty string is an invalid key");
		}
	}


}