Interface Location
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public interface LocationA 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
- Restriction:
- This interface is not intended to be implemented by clients.
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Field Summary
Fields Modifier and Type Field Description static StringCONFIGURATION_FILTERConstant which defines the filter string for acquiring the service which specifies the configuration location.static StringECLIPSE_HOME_FILTERConstant which defines the filter string for acquiring the service which specifies the eclipse home location.static StringINSTALL_FILTERConstant which defines the filter string for acquiring the service which specifies the install location.static StringINSTANCE_FILTERConstant which defines the filter string for acquiring the service which specifies the instance location.static StringUSER_FILTERConstant which defines the filter string for acquiring the service which specifies the user location.
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Method Summary
All Methods Instance Methods Abstract Methods Deprecated Methods Modifier and Type Method Description booleanallowsDefault()Returnstrueif this location allows a default value to be assigned andfalseotherwise.LocationcreateLocation(Location parent, URL defaultValue, boolean readonly)Constructs a new location.URLgetDataArea(String path)Returns a URL to the specified path within this location.URLgetDefault()Returns the default value of this location if any.LocationgetParentLocation()Returns the parent of this location ornullif none is available.URLgetURL()Returns the actualURLof this location.booleanisLocked()Returnstrueif this location is locked andfalseotherwise.booleanisReadOnly()Returnstrueif this location represents a read only location andfalseotherwise.booleanisSet()Returnstrueif this location has a value andfalseotherwise.booleanlock()Attempts to lock this location with a canonical locking mechanism and returntrueif the lock could be acquired.voidrelease()Releases the lock on this location.booleanset(URL value, boolean lock)Sets and optionally locks the location's value to the givenURL.booleanset(URL value, boolean lock, String lockFilePath)Sets and optionally locks the location's value to the givenURLusing the given lock file.booleansetURL(URL value, boolean lock)Deprecated.useset(URL, boolean)instead.
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Field Detail
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INSTANCE_FILTER
static final String INSTANCE_FILTER
Constant which defines the filter string for acquiring the service which specifies the instance location.- Since:
- 3.2
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INSTALL_FILTER
static final String INSTALL_FILTER
Constant which defines the filter string for acquiring the service which specifies the install location.- Since:
- 3.2
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CONFIGURATION_FILTER
static final String CONFIGURATION_FILTER
Constant which defines the filter string for acquiring the service which specifies the configuration location.- Since:
- 3.2
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USER_FILTER
static final String USER_FILTER
Constant which defines the filter string for acquiring the service which specifies the user location.- Since:
- 3.2
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ECLIPSE_HOME_FILTER
static final String ECLIPSE_HOME_FILTER
Constant which defines the filter string for acquiring the service which specifies the eclipse home location.- Since:
- 3.4
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Method Detail
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allowsDefault
boolean allowsDefault()
Returnstrueif this location allows a default value to be assigned andfalseotherwise.- Returns:
- whether or not this location can have a default value assigned
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getDefault
URL getDefault()
Returns the default value of this location if any. If no default is available thennullis returned. Note that even locations which allow defaults may still returnnull.- Returns:
- the default value for this location or
null
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getParentLocation
Location getParentLocation()
Returns the parent of this location ornullif none is available.- Returns:
- the parent of this location or
null
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getURL
URL getURL()
Returns the actualURLof 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 casesnullis returned.- Returns:
- the URL for this location or
nullif none
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isSet
boolean isSet()
Returnstrueif this location has a value andfalseotherwise.- Returns:
- boolean value indicating whether or not the value is set
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isReadOnly
boolean isReadOnly()
Returnstrueif this location represents a read only location andfalseotherwise. The read only character of a location is not in enforced in any way but rather expresses the intention of the location's creator.- Returns:
- boolean value indicating whether the location is read only
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setURL
boolean setURL(URL value, boolean lock) throws IllegalStateException
Deprecated.useset(URL, boolean)instead.Sets and optionally locks the location's value to the givenURL. If the location already has a value an exception is thrown. If locking is requested and fails,falseis returned and theURLof this location is not set.- Parameters:
value- the value of this locationlock- whether or not to lock this location- Returns:
- whether or not the location was successfully set and, if requested, locked.
- Throws:
IllegalStateException- if the location's value is already set
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set
boolean set(URL value, boolean lock) throws IllegalStateException, IOException
Sets and optionally locks the location's value to the givenURL. If the location already has a value an exception is thrown. If locking is requested and fails,falseis returned and theURLof this location is not set.- Parameters:
value- the value of this locationlock- whether or not to lock this location- Returns:
- whether or not the location was successfully set and, if requested, locked.
- Throws:
IllegalStateException- if the location's value is already setIOException- if there was an unexpected problem while acquiring the lock- Since:
- 3.4
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set
boolean set(URL value, boolean lock, String lockFilePath) throws IllegalStateException, IOException
Sets and optionally locks the location's value to the givenURLusing the given lock file. If the location already has a value an exception is thrown. If locking is requested and fails,falseis returned and theURLof this location is not set.- Parameters:
value- the value of this locationlock- whether or not to lock this locationlockFilePath- 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 anullvalue is used then a default lock path will be used for this location.- Returns:
- whether or not the location was successfully set and, if requested, locked.
- Throws:
IllegalStateException- if the location's value is already setIOException- if there was an unexpected problem while acquiring the lock- Since:
- 3.5
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lock
boolean lock() throws IOExceptionAttempts to lock this location with a canonical locking mechanism and returntrueif 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
- Returns:
- true if the lock could be acquired; otherwise false is returned
- Throws:
IOException- if there was an unexpected problem while acquiring the lock
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release
void release()
Releases the lock on this location. If the location is not already locked, no action is taken.
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isLocked
boolean isLocked() throws IOExceptionReturnstrueif this location is locked andfalseotherwise.- Returns:
- boolean value indicating whether or not this location is locked
- Throws:
IOException- if there was an unexpected problem reading the lock- Since:
- 3.4
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createLocation
Location createLocation(Location parent, URL defaultValue, boolean readonly)
Constructs a new location.- Parameters:
parent- the parent location. Anullvalue is allowed.defaultValue- the default value of the location. Anullvalue is allowed.readonly- true if the location is read-only.- Returns:
- a new location.
- Since:
- 3.4
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getDataArea
URL getDataArea(String path) throws IOException
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
IOExceptionwill be thrown if this method is called and the location URL has not been set and there is no default value for this location.- Parameters:
path- the name of the path to get from this location- Returns:
- the URL to the data area with the specified path.
- Throws:
IOException- if the location URL is not already set- Since:
- 3.6
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