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AspectJ tools most notably contains the AspectJ compiler (AJC). AJC applies aspects to Java classes during
compilation, fully replacing Javac for plain Java classes and also compiling native AspectJ or annotation-based
@AspectJ syntax. Furthermore, AJC can weave aspects into existing class files in a post-compile binary weaving step.
This library is a superset of AspectJ weaver and hence also of AspectJ runtime.
/*******************************************************************************
* Copyright (c) 2004, 2022 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
* Christoph Läubrich - Issue #38 - Expose the url of a location as service properties
*******************************************************************************/
package org.eclipse.osgi.service.datalocation;
import java.io.IOException;
import java.net.URL;
/**
* A Location represents a URL which may have a default value, may be read only, may
* or may not have a current value and may be cascaded on to a parent location.
*
* This interface is not intended to be implemented by clients.
*
*
* @since 3.0
* @noimplement This interface is not intended to be implemented by clients.
*/
public interface Location {
/**
* Constant which defines the type value used for the eclipse home location
*
* @since 3.18
*/
public static final String ECLIPSE_HOME_LOCATION_TYPE = "eclipse.home.location"; //$NON-NLS-1$
/**
* Constant which defines the type value used for the user area
*
* @since 3.18
*/
public static final String USER_AREA_TYPE = "osgi.user.area"; //$NON-NLS-1$
/**
* Constant which defines the type value used for the configuration area
*
* @since 3.18
*/
public static final String CONFIGURATION_AREA_TYPE = "osgi.configuration.area"; //$NON-NLS-1$
/**
* Constant which defines the type value used for the install area
*
* @since 3.18
*/
public static final String INSTALL_AREA_TYPE = "osgi.install.area"; //$NON-NLS-1$
/**
* Constant which defines the type value used for the instance area
*
* @since 3.18
*/
public static final String INSTANCE_AREA_TYPE = "osgi.instance.area"; //$NON-NLS-1$
/**
* Constant which defines the service property used for a location to represent
* its type
*
* @see #ECLIPSE_HOME_LOCATION_TYPE
* @see #ECLIPSE_HOME_FILTER
* @see #USER_AREA_TYPE
* @see #USER_FILTER
* @see #CONFIGURATION_AREA_TYPE
* @see #CONFIGURATION_FILTER
* @see #INSTALL_AREA_TYPE
* @see #INSTALL_FILTER
* @see #INSTANCE_AREA_TYPE
* @see #INSTANCE_FILTER
*
* @since 3.18
*/
public static final String SERVICE_PROPERTY_TYPE = "type"; //$NON-NLS-1$
/**
* Constant which defines the service property used for a location to represent
* its url as a {@link String} (using {@link URL#toExternalForm()}), as long as
* the location is not set, this property will be missing, allowing consumers to
* track {@link Location}s that are (not) set yet.
*
* @since 3.18
*/
public static final String SERVICE_PROPERTY_URL = "url"; //$NON-NLS-1$
/**
* Constant which defines the service property used for a location to represent
* its default url as a {@link String} (using {@link URL#toExternalForm()}), if
* the location has no default url this property will be missing.
*
* @since 3.18
*/
public static final String SERVICE_PROPERTY_DEFAULT_URL = "defaultUrl"; //$NON-NLS-1$
/**
* Constant which defines the filter string for acquiring the service which
* specifies the instance location.
*
* @since 3.2
*/
public static final String INSTANCE_FILTER = "(&(objectClass=" + Location.class.getName() + ")(" + SERVICE_PROPERTY_TYPE + "=" + INSTANCE_AREA_TYPE + "))"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
/**
* Constant which defines the filter string for acquiring the service which
* specifies the install location.
*
* @since 3.2
*/
public static final String INSTALL_FILTER = "(&(objectClass=" + Location.class.getName() + ")(" + SERVICE_PROPERTY_TYPE + "=" + INSTALL_AREA_TYPE + "))"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
/**
* Constant which defines the filter string for acquiring the service which
* specifies the configuration location.
*
* @since 3.2
*/
public static final String CONFIGURATION_FILTER = "(&(objectClass=" + Location.class.getName() + ")(" + SERVICE_PROPERTY_TYPE + "=" + CONFIGURATION_AREA_TYPE + "))"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
/**
* Constant which defines the filter string for acquiring the service which
* specifies the user location.
*
* @since 3.2
*/
public static final String USER_FILTER = "(&(objectClass=" + Location.class.getName() + ")(" + SERVICE_PROPERTY_TYPE + "=" + USER_AREA_TYPE + "))"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
/**
* Constant which defines the filter string for acquiring the service which
* specifies the eclipse home location.
*
* @since 3.4
*/
public static final String ECLIPSE_HOME_FILTER = "(&(objectClass=" + Location.class.getName() + ")(" + SERVICE_PROPERTY_TYPE + "=" + ECLIPSE_HOME_LOCATION_TYPE + "))"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
/**
* Returns true if this location allows a default value to be assigned
* and false otherwise.
*
* @return whether or not this location can have a default value assigned
*/
public boolean allowsDefault();
/**
* Returns the default value of this location if any. If no default is available then
* null is returned. Note that even locations which allow defaults may still
* return null.
*
* @return the default value for this location or null
*/
public URL getDefault();
/**
* Returns the parent of this location or null if none is available.
*
* @return the parent of this location or null
*/
public Location getParentLocation();
/**
* Returns the actual {@link URL} of this location. If the location's value has been set,
* that value is returned. If the value is not set and the location allows defaults,
* the value is set to the default and returned. In all other cases null
* is returned.
*
* @return the URL for this location or null if none
*/
public URL getURL();
/**
* Returns true if this location has a value and false
* otherwise.
*
* @return boolean value indicating whether or not the value is set
*/
public boolean isSet();
/**
* Returns true if this location represents a read only location and
* false otherwise. The read only character
* of a location is not in enforced in any way but rather expresses the intention of the
* location's creator.
*
* @return boolean value indicating whether the location is read only
*/
public boolean isReadOnly();
/**
* Sets and optionally locks the location's value to the given {@link URL}. If the location
* already has a value an exception is thrown. If locking is requested and fails, false
* is returned and the {@link URL} of this location is not set.
*
* @param value the value of this location
* @param lock whether or not to lock this location
* @return whether or not the location was successfully set and, if requested, locked.
* @throws IllegalStateException if the location's value is already set
* @deprecated use {@link #set(URL, boolean)} instead.
*/
public boolean setURL(URL value, boolean lock) throws IllegalStateException;
/**
* Sets and optionally locks the location's value to the given {@link URL}. If the location
* already has a value an exception is thrown. If locking is requested and fails, false
* is returned and the {@link URL} of this location is not set.
*
* @param value the value of this location
* @param lock whether or not to lock this location
* @return whether or not the location was successfully set and, if requested, locked.
* @throws IllegalStateException if the location's value is already set
* @throws IOException if there was an unexpected problem while acquiring the lock
* @since 3.4
*/
public boolean set(URL value, boolean lock) throws IllegalStateException, IOException;
/**
* Sets and optionally locks the location's value to the given {@link URL} using the given lock file. If the location
* already has a value an exception is thrown. If locking is requested and fails, false
* is returned and the {@link URL} of this location is not set.
*
* @param value the value of this location
* @param lock whether or not to lock this location
* @param lockFilePath the path to the lock file. This path will be used to establish locks on this location.
* The path may be an absolute path or it may be relative to the given URL. If a null
* value is used then a default lock path will be used for this location.
* @return whether or not the location was successfully set and, if requested, locked.
* @throws IllegalStateException if the location's value is already set
* @throws IOException if there was an unexpected problem while acquiring the lock
* @since 3.5
*/
public boolean set(URL value, boolean lock, String lockFilePath) throws IllegalStateException, IOException;
/**
* Attempts to lock this location with a canonical locking mechanism and return
* true if the lock could be acquired. Not all locations can be
* locked.
*
* Locking a location is advisory only. That is, it does not prevent other applications from
* modifying the same location
*
* @return true if the lock could be acquired; otherwise false is returned
*
* @exception IOException if there was an unexpected problem while acquiring the lock
*/
public boolean lock() throws IOException;
/**
* Releases the lock on this location. If the location is not already locked, no action
* is taken.
*/
public void release();
/**
* Returns true if this location is locked and false
* otherwise.
* @return boolean value indicating whether or not this location is locked
* @throws IOException if there was an unexpected problem reading the lock
* @since 3.4
*/
public boolean isLocked() throws IOException;
/**
* Constructs a new location.
* @param parent the parent location. A null value is allowed.
* @param defaultValue the default value of the location. A null value is allowed.
* @param readonly true if the location is read-only.
* @return a new location.
* @since 3.4
*/
public Location createLocation(Location parent, URL defaultValue, boolean readonly);
/**
* Returns a URL to the specified path within this location. The path
* of the returned URL may not exist yet. It is the responsibility of the
* client to create the content of the data area returned if it does not exist.
*
* This method can be used to obtain a private area within the given location.
* For example use the symbolic name of a bundle to obtain a data area specific
* to that bundle.
*
*
* Clients should check if the location is read only before writing anything
* to the returned data area. An IOException will be thrown if
* this method is called and the location URL has not been set and there is
* no default value for this location.
*
*
* @param path the name of the path to get from this location
* @return the URL to the data area with the specified path.
* @throws IOException if the location URL is not already set
* @since 3.6
*/
public URL getDataArea(String path) throws IOException;
}