Mercurial > jdk8-mips64-public > corba / file revision

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 package org.omg.CORBA;

 /**

  * An object used in <code>Request</code> operations

  * to specify the context object in which context strings

  * must be resolved before being sent along with the request invocation.

  * A <code>Context</code> object

  * contains a list of properties in the form of <code>NamedValue</code>

  * objects. These properties represent information

  * about the client, the environment, or the circumstances of a request

  * and generally are properties that might be inconvenient

  * to pass as parameters.

  * <P>

  * A <code>Context</code> object is created by first calling the

  * <code>ORB</code> method <code>get_default_context</code>

  * and then calling the method <code>create_child</code> on the

  * default context.

  * <P>

  * Each property in a <code>Context</code> object is represented by

  * a <code>NamedValue</code> object.  The property name is contained

  * in the <code>NamedValue</code> object's <code>name</code> field, and

  * the value associated with the name is contained in the <code>Any</code>

  * object that was assigned to the <code>NamedValue</code> object's

  * <code>value</code> field.

  * <P>

  * <code>Context</code> properties can represent a portion of a client's

  * or application's environment that is meant to be propagated to

  * (and made implicitly part of) a server's environment.

  * (Examples might be a window identifier or user preference information).

  * Once a server has been invoked (that is, after the properties are

  * propagated), the server may query its <code>Context</code> object

  * for these properties using the method <code>get_values</code>.

  *

  *<P>

  * When an operation declaration includes a context clause,

  * the stubs and skeletons will have an additional argument

  * added for the context.  When an operation invocation occurs,

  * the ORB causes the properties that were named in the operation

  * definition in IDL and

  * that are present in the client's <code>Context</code> object

  * to be provided in the <code>Context</code> object parameter to

  * the invoked method.

  * <P>

  * <code>Context</code> property names (which are strings)

  * typically have the form of an OMG IDL identifier or

  * a series of OMG IDL identifiers separated by periods.

  * A context property name pattern is either a property name

  * or a property name followed by a single "*".  A property

  * name pattern without a trailing "*" is said to match only

  * itself.  A property name pattern of the form "<name>*" matches any

  * property name that starts with <name> and continues with zero

  * or more additional characters.

  * <P>

  * Property name patterns are used in the context clause of

  * an operation definition and as a parameter for the

  * method <code>Context.get_values</code>.

  * <P>

  * <code>Context</code> objects may be "chained" together to achieve a

  * particular defaulting behavior.  A <code>Context</code>

  * object created with the method <code>create_child</code> will

  * be chained to its parent (the <code>Context</code> object

  * that created it), and that means that the parent will be searched

  * after the child in a search for property names.

  *<P>

  * Properties defined in a particular <code>Context</code> object

  * effectively override those properties in the next higher level.

  * The scope used in a search for properties may be restricted by specifying a

  * starting scope and by using the flag <code>CTX_RESTRICT_SCOPE</code>

  * when invoking the method <code>get_values</code>.

  * <P>

  * A <code>Context</code> object may be named for purposes of specifying

  * a starting search scope.

  *

  * @since   JDK1.2

  */

 public abstract class Context {

     /**

      * Retrieves the name of this <code>Context</code> object.

      *

      * @return                  the name of this <code>Context</code> object

      */

     public abstract String context_name();

     /**

      * Retrieves the parent of this <code>Context</code> object.

      *

      * @return                  the <code>Context</code> object that is the

      *                    parent of this <code>Context</code> object

      */

     public abstract Context parent();

     /**

      * Creates a <code>Context</code> object with the given string as its

      * name and with this <code>Context</code> object set as its parent.

      * <P>

      * The new <code>Context</code> object is chained into its parent

      * <code>Context</code> object.  This means that in a search for

      * matching property names, if a match is not found in this context,

      * the search will continue in the parent.  If that is not successful,

      * the search will continue in the grandparent, if there is one, and

      * so on.

      *

      *

      * @param child_ctx_name    the <code>String</code> object to be set as

      *                        the name of the new <code>Context</code> object

      * @return                  the newly-created child <code>Context</code> object

      *                    initialized with the specified name

      */

     public abstract Context create_child(String child_ctx_name);

     /**

      * Creates a <code>NamedValue</code> object and adds it to this

      * <code>Context</code> object.  The <code>name</code> field of the

      * new <code>NamedValue</code> object is set to the given string,

      * the <code>value</code> field is set to the given <code>Any</code>

      * object, and the <code>flags</code> field is set to zero.

      *

      * @param propname          the name of the property to be set

      * @param propvalue         the <code>Any</code> object to which the

      *                        value of the property will be set.  The

      *                        <code>Any</code> object's <code>value</code>

      *                        field contains the value to be associated

      *                        with the given propname; the

      *                        <code>kind</code> field must be set to

      *                        <code>TCKind.tk_string</code>.

      */

     public abstract void set_one_value(String propname, Any propvalue);

     /**

        I Sets one or more property values in this <code>Context</code>

        * object. The <code>NVList</code> supplied to this method

        * contains one or more <code>NamedValue</code> objects.

        * In each <code>NamedValue</code> object,

        * the <code>name</code> field holds the name of the property, and

        * the <code>flags</code> field must be set to zero.

        * The <code>NamedValue</code> object's <code>value</code> field

        * contains an <code>Any</code> object, which, in turn, contains the value

        * for the property.  Since the value is always a string,

        * the <code>Any</code> object must have the <code>kind</code>

        * field of its <code>TypeCode</code> set to <code>TCKind.tk_string</code>.

        *

        * @param values          an NVList containing the property

        *                                    names and associated values to be set

        *

        * @see #get_values

        * @see org.omg.CORBA.NamedValue

        * @see org.omg.CORBA.Any

        */

     public abstract void set_values(NVList values);

     /**

      * Deletes from this <code>Context</code> object the

      * <code>NamedValue</code> object(s) whose

      * <code>name</code> field matches the given property name.

      * If the <code>String</code> object supplied for

      * <code>propname</code> has a

      * trailing wildcard character ("*"), then

      * all <code>NamedValue</code> objects whose <code>name</code>

      * fields match will be deleted. The search scope is always

      * limited to this <code>Context</code> object.

      * <P>

      * If no matching property is found, an exception is returned.

      *

      * @param propname          name of the property to be deleted

      */

     public abstract void delete_values(String propname);

     /**

      * Retrieves the <code>NamedValue</code> objects whose

      * <code>name</code> field matches the given name or name

      * pattern.   This method allows for wildcard searches,

      * which means that there can be multiple matches and

      * therefore multiple values returned. If the

      * property is not found at the indicated level, the search

      * continues up the context object tree until a match is found or

      * all <code>Context</code> objects in the chain have been exhausted.

      * <P>

      * If no match is found, an error is returned and no property list

      * is returned.

      *

      * @param start_scope               a <code>String</code> object indicating the

      *                context object level at which to initiate the

      *                          search for the specified properties

      *                          (for example, "_USER", "_GROUP", "_SYSTEM"). Valid scope

      *                          names are implementation-specific. If a

      *                          scope name is omitted, the search

      *                          begins with the specified context

      *                          object. If the specified scope name is

      *                          not found, an exception is returned.

      * @param op_flags       an operation flag.  The one flag

      *                that may be specified is <code>CTX_RESTRICT_SCOPE</code>.

      *                If this flag is specified, searching is limited to the

      *                          specified <code>start_scope</code> or this

      *                <code>Context</code> object.

      * @param pattern           the property name whose values are to

      *                          be retrieved. <code>pattern</code> may be a

      *                name or a name with a

      *                          trailing wildcard character ("*").

      *

      * @return          an <code>NVList</code> containing all the property values

      *                (in the form of <code>NamedValue</code> objects)

      *                whose associated property name matches the given name or

      *                name pattern

      * @see #set_values

      * @see org.omg.CORBA.NamedValue

      */

     abstract public NVList get_values(String start_scope, int op_flags,

                                       String pattern);

 };