Interface Context

All Known Subinterfaces:
DirContext, EventContext, EventDirContext, LdapContext
All Known Implementing Classes:
InitialContext, InitialDirContext, InitialLdapContext
public interface Context
This interface represents a naming context, which consists of a set of name-to-object bindings. It contains methods for examining and updating these bindings.

Names

Each name passed as an argument to a Context method is relative to that context. The empty name is used to name the context itself. A name parameter may never be null.

Most of the methods have overloaded versions with one taking a Name parameter and one taking a String. These overloaded versions are equivalent in that if the Name and String parameters are just different representations of the same name, then the overloaded versions of the same methods behave the same. In the method descriptions below, only one version is fully documented. The second version instead has a link to the first: the same documentation applies to both.

For systems that support federation, String name arguments to Context methods are composite names. Name arguments that are instances of CompositeName are treated as composite names, while Name arguments that are not instances of CompositeName are treated as compound names (which might be instances of CompoundName or other implementations of compound names). This allows the results of NameParser.parse() to be used as arguments to the Context methods. Prior to JNDI 1.2, all name arguments were treated as composite names.

Furthermore, for systems that support federation, all names returned in a NamingEnumeration from list() and listBindings() are composite names represented as strings. See CompositeName for the string syntax of names.

For systems that do not support federation, the name arguments (in either Name or String forms) and the names returned in NamingEnumeration may be names in their own namespace rather than names in a composite namespace, at the discretion of the service provider.

Exceptions

All the methods in this interface can throw a NamingException or any of its subclasses. See NamingException and their subclasses for details on each exception.

Concurrent Access

A Context instance is not guaranteed to be synchronized against concurrent access by multiple threads. Threads that need to access a single Context instance concurrently should synchronize amongst themselves and provide the necessary locking. Multiple threads each manipulating a different Context instance need not synchronize. Note that the lookup method, when passed an empty name, will return a new Context instance representing the same naming context.

For purposes of concurrency control, a Context operation that returns a NamingEnumeration is not considered to have completed while the enumeration is still in use, or while any referrals generated by that operation are still being followed.

Parameters

A Name parameter passed to any method of the Context interface or one of its subinterfaces will not be modified by the service provider. The service provider may keep a reference to it for the duration of the operation, including any enumeration of the method's results and the processing of any referrals generated. The caller should not modify the object during this time. A Name returned by any such method is owned by the caller. The caller may subsequently modify it; the service provider may not.

Environment Properties

JNDI applications need a way to communicate various preferences and properties that define the environment in which naming and directory services are accessed. For example, a context might require specification of security credentials in order to access the service. Another context might require that server configuration information be supplied. These are referred to as the environment of a context. The Context interface provides methods for retrieving and updating this environment.

The environment is inherited from the parent context as context methods proceed from one context to the next. Changes to the environment of one context do not directly affect those of other contexts.

It is implementation-dependent when environment properties are used and/or verified for validity. For example, some of the security-related properties are used by service providers to "log in" to the directory. This login process might occur at the time the context is created, or the first time a method is invoked on the context. When, and whether this occurs at all, is implementation-dependent. When environment properties are added or removed from the context, verifying the validity of the changes is again implementation-dependent. For example, verification of some properties might occur at the time the change is made, or at the time the next operation is performed on the context, or not at all.

Any object with a reference to a context may examine that context's environment. Sensitive information such as clear-text passwords should not be stored there unless the implementation is known to protect it.

Resource Files

To simplify the task of setting up the environment required by a JNDI application, application components and service providers may be distributed along with resource files. A JNDI resource file is a file in the properties file format (see java.util.Properties), containing a list of key/value pairs. The key is the name of the property (e.g. "java.naming.factory.object") and the value is a string in the format defined for that property. Here is an example of a JNDI resource file:

java.naming.factory.object=com.sun.jndi.ldap.AttrsToCorba:com.wiz.from.Person java.naming.factory.state=com.sun.jndi.ldap.CorbaToAttrs:com.wiz.from.Person java.naming.factory.control=com.sun.jndi.ldap.ResponseControlFactory
The JNDI class library reads the resource files and makes the property values freely available. Thus JNDI resource files should be considered to be "world readable", and sensitive information such as clear-text passwords should not be stored there.

There are two kinds of JNDI resource files: provider and application.

Provider Resource Files

Each service provider has an optional resource that lists properties specific to that provider. The name of this resource is:
[prefix/]jndiprovider.properties
where prefix is the package name of the provider's context implementation(s), with each period (".") converted to a slash ("/"). For example, suppose a service provider defines a context implementation with class name com.sun.jndi.ldap.LdapCtx. The provider resource for this provider is named com/sun/jndi/ldap/jndiprovider.properties. If the class is not in a package, the resource's name is simply jndiprovider.properties.

Certain methods in the JNDI class library make use of the standard JNDI properties that specify lists of JNDI factories:

  • java.naming.factory.object
  • java.naming.factory.state
  • java.naming.factory.control
  • java.naming.factory.url.pkgs
The JNDI library will consult the provider resource file when determining the values of these properties. Properties other than these may be set in the provider resource file at the discretion of the service provider. The service provider's documentation should clearly state which properties are allowed; other properties in the file will be ignored.

Application Resource Files

When an application is deployed, it will generally have several codebase directories and JARs in its classpath. JNDI locates (using ClassLoader.getResources()) all application resource files named jndi.properties in the classpath. In addition, if the Java installation directory contains a built-in properties file, typically conf/jndi.properties, JNDI treats it as an additional application resource file. All of the properties contained in these files are placed into the environment of the initial context. This environment is then inherited by other contexts.

For each property found in more than one application resource file, JNDI uses the first value found or, in a few cases where it makes sense to do so, it concatenates all of the values (details are given below). For example, if the "java.naming.factory.object" property is found in three jndi.properties resource files, the list of object factories is a concatenation of the property values from all three files. Using this scheme, each deployable component is responsible for listing the factories that it exports. JNDI automatically collects and uses all of these export lists when searching for factory classes.

Search Algorithm for Properties

When JNDI constructs an initial context, the context's environment is initialized with properties defined in the environment parameter passed to the constructor, the system properties, and the application resource files. See InitialContext for details. This initial environment is then inherited by other context instances.

When the JNDI class library needs to determine the value of a property, it does so by merging the values from the following two sources, in order:

  1. The environment of the context being operated on.
  2. The provider resource file (jndiprovider.properties) for the context being operated on.
For each property found in both of these two sources, JNDI determines the property's value as follows. If the property is one of the standard JNDI properties that specify a list of JNDI factories (listed above), the values are concatenated into a single colon-separated list. For other properties, only the first value found is used.

When a service provider needs to determine the value of a property, it will generally take that value directly from the environment. A service provider may define provider-specific properties to be placed in its own provider resource file. In that case it should merge values as described in the previous paragraph.

In this way, each service provider developer can specify a list of factories to use with that service provider. These can be modified by the application resources specified by the deployer of the application, which in turn can be modified by the user.

Since:
1.3

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    AUTHORITATIVE
    Constant that holds the name of the environment property for specifying the authoritativeness of the service requested.
    static final String
    BATCHSIZE
    Constant that holds the name of the environment property for specifying the batch size to use when returning data via the service's protocol.
    static final String
    DNS_URL
    Constant that holds the name of the environment property for specifying the DNS host and domain names to use for the JNDI URL context (for example, "dns://somehost/wiz.com").
    static final String
    INITIAL_CONTEXT_FACTORY
    Constant that holds the name of the environment property for specifying the initial context factory to use.
    static final String
    LANGUAGE
    Constant that holds the name of the environment property for specifying the preferred language to use with the service.
    static final String
    OBJECT_FACTORIES
    Constant that holds the name of the environment property for specifying the list of object factories to use.
    static final String
    PROVIDER_URL
    Constant that holds the name of the environment property for specifying configuration information for the service provider to use.
    static final String
    REFERRAL
    Constant that holds the name of the environment property for specifying how referrals encountered by the service provider are to be processed.
    static final String
    SECURITY_AUTHENTICATION
    Constant that holds the name of the environment property for specifying the security level to use.
    static final String
    SECURITY_CREDENTIALS
    Constant that holds the name of the environment property for specifying the credentials of the principal for authenticating the caller to the service.
    static final String
    SECURITY_PRINCIPAL
    Constant that holds the name of the environment property for specifying the identity of the principal for authenticating the caller to the service.
    static final String
    SECURITY_PROTOCOL
    Constant that holds the name of the environment property for specifying the security protocol to use.
    static final String
    STATE_FACTORIES
    Constant that holds the name of the environment property for specifying the list of state factories to use.
    static final String
    URL_PKG_PREFIXES
    Constant that holds the name of the environment property for specifying the list of package prefixes to use when loading in URL context factories.

  • Method Summary

    Modifier and Type
    Method
    Description
    Object
    addToEnvironment(String propName, Object propVal)
    Adds a new environment property to the environment of this context.
    void
    bind(String name, Object obj)
    Binds a name to an object.
    void
    bind(Name name, Object obj)
    Binds a name to an object.
    void
    close()
    Closes this context.
    String
    composeName(String name, String prefix)
    Composes the name of this context with a name relative to this context.
    Name
    composeName(Name name, Name prefix)
    Composes the name of this context with a name relative to this context.
    Context
    createSubcontext(String name)
    Creates and binds a new context.
    Context
    createSubcontext(Name name)
    Creates and binds a new context.
    void
    destroySubcontext(String name)
    Destroys the named context and removes it from the namespace.
    void
    destroySubcontext(Name name)
    Destroys the named context and removes it from the namespace.
    Hashtable<?,?>
    getEnvironment()
    Retrieves the environment in effect for this context.
    String
    getNameInNamespace()
    Retrieves the full name of this context within its own namespace.
    NameParser
    getNameParser(String name)
    Retrieves the parser associated with the named context.
    NameParser
    getNameParser(Name name)
    Retrieves the parser associated with the named context.
    NamingEnumeration<NameClassPair>
    list(String name)
    Enumerates the names bound in the named context, along with the class names of objects bound to them.
    NamingEnumeration<NameClassPair>
    list(Name name)
    Enumerates the names bound in the named context, along with the class names of objects bound to them.
    NamingEnumeration<Binding>
    listBindings(String name)
    Enumerates the names bound in the named context, along with the objects bound to them.
    NamingEnumeration<Binding>
    listBindings(Name name)
    Enumerates the names bound in the named context, along with the objects bound to them.
    Object
    lookup(String name)
    Retrieves the named object.
    Object
    lookup(Name name)
    Retrieves the named object.
    Object
    lookupLink(String name)
    Retrieves the named object, following links except for the terminal atomic component of the name.
    Object
    lookupLink(Name name)
    Retrieves the named object, following links except for the terminal atomic component of the name.
    void
    rebind(String name, Object obj)
    Binds a name to an object, overwriting any existing binding.
    void
    rebind(Name name, Object obj)
    Binds a name to an object, overwriting any existing binding.
    Object
    removeFromEnvironment(String propName)
    Removes an environment property from the environment of this context.
    void
    rename(String oldName, String newName)
    Binds a new name to the object bound to an old name, and unbinds the old name.
    void
    rename(Name oldName, Name newName)
    Binds a new name to the object bound to an old name, and unbinds the old name.
    void
    unbind(String name)
    Unbinds the named object.
    void
    unbind(Name name)
    Unbinds the named object.

  • Field Details

  • Method Details

    • lookup

      Object lookup(Name name) throws NamingException
      Retrieves the named object. If name is empty, returns a new instance of this context (which represents the same naming context as this context, but its environment may be modified independently and it may be accessed concurrently).
      Parameters:
      name - the name of the object to look up
      Returns:
      the object bound to name
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • lookup

      Object lookup(String name) throws NamingException
      Retrieves the named object. See lookup(Name) for details.
      Parameters:
      name - the name of the object to look up
      Returns:
      the object bound to name
      Throws:
      NamingException - if a naming exception is encountered

    • bind

      void bind(Name name, Object obj) throws NamingException
      Binds a name to an object. All intermediate contexts and the target context (that named by all but terminal atomic component of the name) must already exist.
      Parameters:
      name - the name to bind; may not be empty
      obj - the object to bind; possibly null
      Throws:
      NameAlreadyBoundException - if name is already bound
      InvalidAttributesException - if object did not supply all mandatory attributes
      NamingException - if a naming exception is encountered
      See Also:

    • bind

      void bind(String name, Object obj) throws NamingException
      Binds a name to an object. See bind(Name, Object) for details.
      Parameters:
      name - the name to bind; may not be empty
      obj - the object to bind; possibly null
      Throws:
      NameAlreadyBoundException - if name is already bound
      InvalidAttributesException - if object did not supply all mandatory attributes
      NamingException - if a naming exception is encountered

    • rebind

      void rebind(Name name, Object obj) throws NamingException
      Binds a name to an object, overwriting any existing binding. All intermediate contexts and the target context (that named by all but terminal atomic component of the name) must already exist.

      If the object is a DirContext, any existing attributes associated with the name are replaced with those of the object. Otherwise, any existing attributes associated with the name remain unchanged.

      Parameters:
      name - the name to bind; may not be empty
      obj - the object to bind; possibly null
      Throws:
      InvalidAttributesException - if object did not supply all mandatory attributes
      NamingException - if a naming exception is encountered
      See Also:

    • rebind

      void rebind(String name, Object obj) throws NamingException
      Binds a name to an object, overwriting any existing binding. See rebind(Name, Object) for details.
      Parameters:
      name - the name to bind; may not be empty
      obj - the object to bind; possibly null
      Throws:
      InvalidAttributesException - if object did not supply all mandatory attributes
      NamingException - if a naming exception is encountered

    • unbind

      void unbind(Name name) throws NamingException
      Unbinds the named object. Removes the terminal atomic name in name from the target context--that named by all but the terminal atomic part of name.

      This method is idempotent. It succeeds even if the terminal atomic name is not bound in the target context, but throws NameNotFoundException if any of the intermediate contexts do not exist.

      Any attributes associated with the name are removed. Intermediate contexts are not changed.

      Parameters:
      name - the name to unbind; may not be empty
      Throws:
      NameNotFoundException - if an intermediate context does not exist
      NamingException - if a naming exception is encountered
      See Also:

    • unbind

      void unbind(String name) throws NamingException
      Unbinds the named object. See unbind(Name) for details.
      Parameters:
      name - the name to unbind; may not be empty
      Throws:
      NameNotFoundException - if an intermediate context does not exist
      NamingException - if a naming exception is encountered

    • rename

      void rename(Name oldName, Name newName) throws NamingException
      Binds a new name to the object bound to an old name, and unbinds the old name. Both names are relative to this context. Any attributes associated with the old name become associated with the new name. Intermediate contexts of the old name are not changed.
      Parameters:
      oldName - the name of the existing binding; may not be empty
      newName - the name of the new binding; may not be empty
      Throws:
      NameAlreadyBoundException - if newName is already bound
      NamingException - if a naming exception is encountered
      See Also:

    • rename

      void rename(String oldName, String newName) throws NamingException
      Binds a new name to the object bound to an old name, and unbinds the old name. See rename(Name, Name) for details.
      Parameters:
      oldName - the name of the existing binding; may not be empty
      newName - the name of the new binding; may not be empty
      Throws:
      NameAlreadyBoundException - if newName is already bound
      NamingException - if a naming exception is encountered

    • list

      NamingEnumeration<NameClassPair> list(Name name) throws NamingException
      Enumerates the names bound in the named context, along with the class names of objects bound to them. The contents of any subcontexts are not included.

      If a binding is added to or removed from this context, its effect on an enumeration previously returned is undefined.

      Parameters:
      name - the name of the context to list
      Returns:
      an enumeration of the names and class names of the bindings in this context. Each element of the enumeration is of type NameClassPair.
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • list

      NamingEnumeration<NameClassPair> list(String name) throws NamingException
      Enumerates the names bound in the named context, along with the class names of objects bound to them. See list(Name) for details.
      Parameters:
      name - the name of the context to list
      Returns:
      an enumeration of the names and class names of the bindings in this context. Each element of the enumeration is of type NameClassPair.
      Throws:
      NamingException - if a naming exception is encountered

    • listBindings

      NamingEnumeration<Binding> listBindings(Name name) throws NamingException
      Enumerates the names bound in the named context, along with the objects bound to them. The contents of any subcontexts are not included.

      If a binding is added to or removed from this context, its effect on an enumeration previously returned is undefined.

      Parameters:
      name - the name of the context to list
      Returns:
      an enumeration of the bindings in this context. Each element of the enumeration is of type Binding.
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • listBindings

      NamingEnumeration<Binding> listBindings(String name) throws NamingException
      Enumerates the names bound in the named context, along with the objects bound to them. See listBindings(Name) for details.
      Parameters:
      name - the name of the context to list
      Returns:
      an enumeration of the bindings in this context. Each element of the enumeration is of type Binding.
      Throws:
      NamingException - if a naming exception is encountered

    • destroySubcontext

      void destroySubcontext(Name name) throws NamingException
      Destroys the named context and removes it from the namespace. Any attributes associated with the name are also removed. Intermediate contexts are not destroyed.

      This method is idempotent. It succeeds even if the terminal atomic name is not bound in the target context, but throws NameNotFoundException if any of the intermediate contexts do not exist.

      In a federated naming system, a context from one naming system may be bound to a name in another. One can subsequently look up and perform operations on the foreign context using a composite name. However, an attempt destroy the context using this composite name will fail with NotContextException, because the foreign context is not a "subcontext" of the context in which it is bound. Instead, use unbind() to remove the binding of the foreign context. Destroying the foreign context requires that the destroySubcontext() be performed on a context from the foreign context's "native" naming system.

      Parameters:
      name - the name of the context to be destroyed; may not be empty
      Throws:
      NameNotFoundException - if an intermediate context does not exist
      NotContextException - if the name is bound but does not name a context, or does not name a context of the appropriate type
      ContextNotEmptyException - if the named context is not empty
      NamingException - if a naming exception is encountered
      See Also:

    • destroySubcontext

      void destroySubcontext(String name) throws NamingException
      Destroys the named context and removes it from the namespace. See destroySubcontext(Name) for details.
      Parameters:
      name - the name of the context to be destroyed; may not be empty
      Throws:
      NameNotFoundException - if an intermediate context does not exist
      NotContextException - if the name is bound but does not name a context, or does not name a context of the appropriate type
      ContextNotEmptyException - if the named context is not empty
      NamingException - if a naming exception is encountered

    • createSubcontext

      Context createSubcontext(Name name) throws NamingException
      Creates and binds a new context. Creates a new context with the given name and binds it in the target context (that named by all but terminal atomic component of the name). All intermediate contexts and the target context must already exist.
      Parameters:
      name - the name of the context to create; may not be empty
      Returns:
      the newly created context
      Throws:
      NameAlreadyBoundException - if name is already bound
      InvalidAttributesException - if creation of the subcontext requires specification of mandatory attributes
      NamingException - if a naming exception is encountered
      See Also:

    • createSubcontext

      Context createSubcontext(String name) throws NamingException
      Creates and binds a new context. See createSubcontext(Name) for details.
      Parameters:
      name - the name of the context to create; may not be empty
      Returns:
      the newly created context
      Throws:
      NameAlreadyBoundException - if name is already bound
      InvalidAttributesException - if creation of the subcontext requires specification of mandatory attributes
      NamingException - if a naming exception is encountered

    • lookupLink

      Object lookupLink(Name name) throws NamingException
      Retrieves the named object, following links except for the terminal atomic component of the name. If the object bound to name is not a link, returns the object itself.
      Parameters:
      name - the name of the object to look up
      Returns:
      the object bound to name, not following the terminal link (if any).
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • lookupLink

      Object lookupLink(String name) throws NamingException
      Retrieves the named object, following links except for the terminal atomic component of the name. See lookupLink(Name) for details.
      Parameters:
      name - the name of the object to look up
      Returns:
      the object bound to name, not following the terminal link (if any)
      Throws:
      NamingException - if a naming exception is encountered

    • getNameParser

      NameParser getNameParser(Name name) throws NamingException
      Retrieves the parser associated with the named context. In a federation of namespaces, different naming systems will parse names differently. This method allows an application to get a parser for parsing names into their atomic components using the naming convention of a particular naming system. Within any single naming system, NameParser objects returned by this method must be equal (using the equals() test).
      Parameters:
      name - the name of the context from which to get the parser
      Returns:
      a name parser that can parse compound names into their atomic components
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • getNameParser

      NameParser getNameParser(String name) throws NamingException
      Retrieves the parser associated with the named context. See getNameParser(Name) for details.
      Parameters:
      name - the name of the context from which to get the parser
      Returns:
      a name parser that can parse compound names into their atomic components
      Throws:
      NamingException - if a naming exception is encountered

    • composeName

      Name composeName(Name name, Name prefix) throws NamingException
      Composes the name of this context with a name relative to this context. Given a name (name) relative to this context, and the name (prefix) of this context relative to one of its ancestors, this method returns the composition of the two names using the syntax appropriate for the naming system(s) involved. That is, if name names an object relative to this context, the result is the name of the same object, but relative to the ancestor context. None of the names may be null.

      For example, if this context is named "wiz.com" relative to the initial context, then 

        composeName("east", "wiz.com")
      might return "east.wiz.com". If instead this context is named "org/research", then 
        composeName("user/jane", "org/research")
      might return "org/research/user/jane" while 
        composeName("user/jane", "research")
      returns "research/user/jane".
      Parameters:
      name - a name relative to this context
      prefix - the name of this context relative to one of its ancestors
      Returns:
      the composition of prefix and name
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • composeName

      String composeName(String name, String prefix) throws NamingException
      Composes the name of this context with a name relative to this context. See composeName(Name, Name) for details.
      Parameters:
      name - a name relative to this context
      prefix - the name of this context relative to one of its ancestors
      Returns:
      the composition of prefix and name
      Throws:
      NamingException - if a naming exception is encountered

    • addToEnvironment

      Object addToEnvironment(String propName, Object propVal) throws NamingException
      Adds a new environment property to the environment of this context. If the property already exists, its value is overwritten. See class description for more details on environment properties.
      Parameters:
      propName - the name of the environment property to add; may not be null
      propVal - the value of the property to add; may not be null
      Returns:
      the previous value of the property, or null if the property was not in the environment before
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • removeFromEnvironment

      Object removeFromEnvironment(String propName) throws NamingException
      Removes an environment property from the environment of this context. See class description for more details on environment properties.
      Parameters:
      propName - the name of the environment property to remove; may not be null
      Returns:
      the previous value of the property, or null if the property was not in the environment
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • getEnvironment

      Hashtable<?,?> getEnvironment() throws NamingException
      Retrieves the environment in effect for this context. See class description for more details on environment properties.

      The caller should not make any changes to the object returned: their effect on the context is undefined. The environment of this context may be changed using addToEnvironment() and removeFromEnvironment().

      Returns:
      the environment of this context; never null
      Throws:
      NamingException - if a naming exception is encountered
      See Also:

    • close

      void close() throws NamingException
      Closes this context. This method releases this context's resources immediately, instead of waiting for them to be released automatically by the garbage collector.

      This method is idempotent: invoking it on a context that has already been closed has no effect. Invoking any other method on a closed context is not allowed, and results in undefined behaviour.

      Throws:
      NamingException - if a naming exception is encountered

    • getNameInNamespace

      String getNameInNamespace() throws NamingException
      Retrieves the full name of this context within its own namespace.

      Many naming services have a notion of a "full name" for objects in their respective namespaces. For example, an LDAP entry has a distinguished name, and a DNS record has a fully qualified name. This method allows the client application to retrieve this name. The string returned by this method is not a JNDI composite name and should not be passed directly to context methods. In naming systems for which the notion of full name does not make sense, OperationNotSupportedException is thrown.

      Returns:
      this context's name in its own namespace; never null
      Throws:
      OperationNotSupportedException - if the naming system does not have the notion of a full name
      NamingException - if a naming exception is encountered
      Since:
      1.3