Package org.eclipse.core.runtime.preferences

Interface IPreferencesService

public interface IPreferencesService
The preference service provides facilities for dealing with the default scope precedence lookup order, querying the preference store for values using this order, accessing the root of the preference store node hierarchy, and importing/exporting preferences.

The default-default preference search look-up order as defined by the platform is: project, instance, configuration, default.

This interface is not intended to be implemented by clients.

Since:
3.0
Restriction:
This interface is not intended to be implemented by clients.
Restriction:
This interface is not intended to be extended by clients.

  • Method Details

    • get

      String get(String key, String defaultValue, Preferences[] nodes)
      Lookup the given key in the specified preference nodes in the given order. Return the value from the first node the key is found in. If the key is not defined in any of the given nodes, then return the specified default value.

      Immediately returns the default value if the node list is null. If any of the individual entries in the node list are null then skip over them and move on to the next node in the list.

      Parameters:
      key - the preference key
      defaultValue - the default value
      nodes - the list of nodes to search, or null
      Returns:
      the stored preference value or the specified default value
      See Also:

    • getBoolean

      boolean getBoolean(String qualifier, String key, boolean defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getByteArray

      byte[] getByteArray(String qualifier, String key, byte[] defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getDouble

      double getDouble(String qualifier, String key, double defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getFloat

      float getFloat(String qualifier, String key, float defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getInt

      int getInt(String qualifier, String key, int defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getLong

      long getLong(String qualifier, String key, long defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getString

      String getString(String qualifier, String key, String defaultValue, IScopeContext[] contexts)
      Return the value stored in the preference store for the given key. If the key is not defined then return the specified default value. Use the canonical scope lookup order for finding the preference value.

      The semantics of this method are to calculate the appropriate Preferences nodes in the preference hierarchy to use and then call the get(String, String, Preferences[]) method. The order of the nodes is calculated by consulting the default scope lookup order as set by setDefaultLookupOrder(String, String, String[]).

      The specified key may either refer to a simple key or be the concatenation of the path of a child node and key. If the key contains a slash ("/") character, then a double-slash must be used to denote the end of they child path and the beginning of the key. Otherwise it is assumed that the key is the last segment of the path. The following are some examples of keys and their meanings:

      • "a" - look for a value for the property "a"
      • "//a" - look for a value for the property "a"
      • "///a" - look for a value for the property "/a"
      • "//a//b" - look for a value for the property "a//b"
      • "a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b/c" - look in the child node "a/b" for property "c"
      • "/a/b//c" - look in the child node "a/b" for the property "c"
      • "a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c/d" - look in the child node "a/b" for the property "c/d"
      • "/a/b//c//d" - look in the child node "a/b" for the property "c//d"

      The scope look-up order is determined by the preference service default lookup order, not by the order of the scope contexts that are being passed in. The context objects are only consulted to help determine which nodes to look in, not the order of the nodes.

      Callers may specify an array of scope context objects to aid in the determination of the correct nodes. For each entry in the lookup order, the array of contexts is consulted and if one matching the scope exists, then it is used to calculate the node. Otherwise a default calculation algorithm is used.

      An example of a qualifier for an Eclipse 2.1 preference is the plug-in identifier. (e.g. "org.eclipse.core.resources" for "description.autobuild")

      Parameters:
      qualifier - a namespace qualifier for the preference
      key - the name of the preference (optionally including its path)
      defaultValue - the value to use if the preference is not defined
      contexts - optional context objects to help scopes determine which nodes to search, or null
      Returns:
      the value of the preference or the given default value
      See Also:

    • getRootNode

      IEclipsePreferences getRootNode()
      Return the root node of the Eclipse preference hierarchy.
      Returns:
      the root of the hierarchy

    • exportPreferences

      IStatus exportPreferences(IEclipsePreferences node, OutputStream output, String[] excludesList) throws CoreException
      Exports all preferences for the given preference node and all its children to the specified output stream. It is the responsibility of the client to close the given output stream.

      If the given export list is null then all preferences for all sub-nodes of the given node are exported to the given stream. Otherwise the export list is consulted before exporting each preference value. If there is a string match then the preference is not exported. The exclusion can also occur at a per-node level. Wild cards are not accepted in the excludes list as a basic String compare is done. The basic algorithm is similar to the following: 

       String fullPath = node.absolutePath() + '/' + key;
 if (!fullPath.startsWith(excludesList[i]))
        // export preference

      The values stored in the resulting stream are suitable for later being read by the by importPreferences(InputStream) or readPreferences(InputStream) methods.

      Parameters:
      node - the node to treat as the root of the export
      output - the stream to write to
      excludesList - a list of path prefixes to exclude from the export, or null
      Returns:
      a status object describing success or detailing failure reasons
      Throws:
      CoreException - if there was a problem exporting the preferences
      IllegalArgumentException - if the node or stream is null
      See Also:

    • importPreferences

      IStatus importPreferences(InputStream input) throws CoreException
      Loads preferences from the given file and stores them in the preferences store. Existing values are over-ridden by those from the stream. The stream must not be null and is closed upon return from this method.

      This file must have been written by the exportPreferences(IEclipsePreferences, OutputStream, String[]) method.

      This method is equivalent to calling applyPreferences(readPreferences(input));.

      Parameters:
      input - the stream to load the preferences from
      Returns:
      a status object describing success or detailing failure reasons
      Throws:
      CoreException - if there are problems importing the preferences
      IllegalArgumentException - if the stream is null
      See Also:

    • applyPreferences

      IStatus applyPreferences(IExportedPreferences preferences) throws CoreException
      Take the given preference tree and apply it to the Eclipse global preference hierarchy. If a node is an export root, then treat the operation for that node as an overwrite rather than a merge. That is, remove the node from the global tree before adding any preferences contained in it or its children.

      The given preferences object must not be null.

      Before the tree is applied to the global preference tree, the registered PreferenceModifyListener objects are called and given the opportunity to modify the tree.

      Parameters:
      preferences - the preferences to apply globally
      Returns:
      status object indicating success or failure
      Throws:
      IllegalArgumentException - if the preferences are null
      CoreException - if there are problems applying the preferences
      See Also:

    • readPreferences

      IExportedPreferences readPreferences(InputStream input) throws CoreException
      Read from the given input stream and create a node hierarchy representing the preferences and their values. The given input stream must not be null. The result of this function is suitable for passing as an argument to applyPreferences(IExportedPreferences).

      It is assumed the contents of the input stream have been written by exportPreferences(IEclipsePreferences, OutputStream, String[]).

      Parameters:
      input - the input stream to read from
      Returns:
      the node hierarchy representing the stream contents
      Throws:
      IllegalArgumentException - if the given stream is null
      CoreException - if there are problems reading the preferences
      See Also:

    • getDefaultLookupOrder

      String[] getDefaultLookupOrder(String qualifier, String key)
      Return an array with the default lookup order for the preference keyed by the given qualifier and simple name. Return null if no default has been set.

      The lookup order returned is based on an exact match to the specified qualifier and simple name. For instance, if the given key is non-null and no default lookup order is found, the default lookup order for the qualifier (and a null key) is NOT returned. Clients should call getLookupOrder(String, String) if they desire this behavior.

      Parameters:
      qualifier - the namespace qualifier for the preference
      key - the preference name or null
      Returns:
      the scope order or null
      See Also:

    • getLookupOrder

      String[] getLookupOrder(String qualifier, String key)
      Return an array with the lookup order for the preference keyed by the given qualifier and simple name.

      First do an exact match lookup with the given qualifier and simple name. If a match is found then return it. Otherwise if the key is non-null then do a lookup based on only the qualifier and return the set value. Return the default-default order as defined by the platform if no order has been set.

      Parameters:
      qualifier - the namespace qualifier for the preference
      key - the preference name or null
      Returns:
      the scope order
      Throws:
      IllegalArgumentException - if the qualifier is null
      See Also:

    • setDefaultLookupOrder

      void setDefaultLookupOrder(String qualifier, String key, String[] order)
      Set the default scope lookup order for the preference keyed by the given qualifier and simple name. If the given order is null then the set ordering (if it exists) is removed.

      If the given simple name is null then set the given lookup order to be used for all keys with the given qualifier.

      Note that the default lookup order is not persisted across platform invocations.

      Parameters:
      qualifier - the namespace qualifier for the preference
      key - the preference name or null
      order - the lookup order or null
      Throws:
      IllegalArgumentException -
      • if the qualifier is null
      • if an entry in the order array is null (the array itself is allowed to be null
      See Also:

    • exportPreferences

      void exportPreferences(IEclipsePreferences node, IPreferenceFilter[] filters, OutputStream output) throws CoreException
      Export the preference tree rooted at the given node, to the specified output stream. Apply the given list of preference filters, only exporting preference node and keys which are applicable to at least one filter in the list.

      The given node and output stream must not be null. If the list of filters is null or empty then do nothing.

      It is the responsibility of the client to close the given output stream.

      Parameters:
      node - the tree to export
      filters - the list of filters to export
      output - the stream to export to
      Throws:
      CoreException - if there was a problem exporting the preferences
      Since:
      3.1
      See Also:

    • matches

      IPreferenceFilter[] matches(IEclipsePreferences node, IPreferenceFilter[] filters) throws CoreException
      Return a list of filters which match the given tree and is a subset of the given filter list. If the specified list of filters is null, empty, or there are no matches, then return an empty list.
      Parameters:
      node - the tree to match against
      filters - the list of filters to match against
      Returns:
      the array of matching transfers
      Throws:
      CoreException - if there are problems during matching
      Since:
      3.1
      See Also:

    • applyPreferences

      void applyPreferences(IEclipsePreferences node, IPreferenceFilter[] filters) throws CoreException
      Apply the preference tree rooted at the given node, to the system's preference tree. The list of preference filters will act as a filter and only preferences in the tree which apply to at least one filter in the list, will be applied.

      If the list of filters is null or empty then do nothing.

      Before the tree is applied to the global preference tree, the registered PreferenceModifyListener objects are called and given the opportunity to modify the tree.

      Parameters:
      node - the tree to consider applying
      filters - the filters to use
      Throws:
      CoreException - if there are problems applying the preferences
      Since:
      3.1
      See Also: