Package nl.tudelft.simulation.naming.context

Class JvmContext

java.lang.Object
org.djutils.event.LocalEventProducer
nl.tudelft.simulation.naming.context.JvmContext
All Implemented Interfaces:
ContextInterface, org.djutils.event.EventProducer
public class JvmContext extends org.djutils.event.LocalEventProducer implements ContextInterface
The JvmContext is an in-memory, thread-safe context implementation of the ContextInterface.

Copyright (c) 2020-2025 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information DSOL Manual. The DSOL project is distributed under a three-clause BSD-style license, which can be found at DSOL License.

Author:
Alexander Verbraeck

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    JvmContext.ContextName
    Record with Context and Name combination.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected Map<String,Object>
    elements
    the children.
    protected ContextInterface
    parent
    the parent context.

    Fields inherited from interface nl.tudelft.simulation.naming.context.ContextInterface

    OBJECT_ADDED_EVENT, OBJECT_CHANGED_EVENT, OBJECT_REMOVED_EVENT, REPLACE_SEPARATOR, ROOT, SEPARATOR

    Fields inherited from interface org.djutils.event.EventProducer

    FIRST_POSITION, LAST_POSITION

  • Constructor Summary

    Constructors
    Constructor
    Description
    JvmContext(String atomicName)
    constructs a new root JvmContext.
    JvmContext(ContextInterface parent, String atomicName)
    Constructs a new JvmContext.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    bind(String name, Object object)
    Binds an object into the Context using the name.
    Map<String,Object>
    bindings()
    Returns a (raw) map of bindings in the current context, mapping the name on the registered objects.
    void
    bindObject(Object object)
    Binds an object into the Context using the toString() method of the object as the key.
    void
    bindObject(String key, Object object)
    Binds an object into this Context using the key.
    void
    checkCircular(Object newObject)
    Check whether a circular reference would occur when the object would be inserted into the current context.
    void
    close()
    Closes the context and removes all content from the context.
    ContextInterface
    createSubcontext(String name)
    Creates and binds a new context into the current Context using the name.
    protected void
    destroy(ContextInterface context)
    Recursively unbind and destroy all keys and subcontexts from the given context, leaving it empty.
    void
    destroySubcontext(String name)
    Removes the binding for an existing, empty subcontext with the given name, and recursively unbinds all objects and contexts in the context indicated by the name.
    boolean
    exists(String name)
    Indicates whether an object with the given name has been registered in the Context.
    void
    fireObjectChangedEventKey(String key)
    Fire an OBJECT_CHANGED_EVENT for an object with the given key in the current context.
    void
    fireObjectChangedEventValue(Object object)
    Fire an OBJECT_CHANGED_EVENT for an object within the current context.
    Object
    get(String name)
    Retrieves the named object from the Context.
    String
    getAbsolutePath()
    Returns the absolute path for this context, or an empty string when this is the root context.
    String
    getAtomicName()
    Retrieves the atomic name of this context.
    Object
    getObject(String key)
    Retrieves the named object from the Context.
    ContextInterface
    getParent()
    Retrieves the parent context for this context, or null when this is the root context.
    ContextInterface
    getRootContext()
    Retrieves the root context for this context, or the current context when this is the root context.
    boolean
    hasKey(String key)
    Indicates whether the key has been registered in the current Context.
    boolean
    hasObject(Object object)
    Indicates whether the object has been registered (once or more) in the current Context.
    boolean
    isEmpty()
    Indicates whether the current context is empty.
    Set<String>
    keySet()
    Returns a set of registered keys in the current context.
    protected JvmContext.ContextName
    lookup(String name)
    Take a (compound) name such as "sub1/sub2/key" or "key" or "/sub/key" and lookup the final sub-context of the path, and store it in the ContextName.
    protected ContextInterface
    lookupAndBuild(String name)
    Take a (compound) name such as "sub1/sub2/key" or "key" or "/sub/key" and lookup and/or create all intermediate contexts as well as the final sub-context of the path.
    void
    rebind(String name, Object object)
    Replaces an object in the Context with the given name, or registers the object when a registration with the name does not exist yet.
    void
    rebindObject(String key, Object object)
    Replaces an object in this Context with the given key, or registers the object when a registration with the key does not exist yet.
    void
    rename(String oldName, String newName)
    Replaces the name under which an object has been registered in the Context.
    String
    toString()
     
    String
    toString(boolean verbose)
    Return a String with the hierarchical content of the Context in case verbose is true; otherwise return the atomic name.
    void
    unbind(String name)
    Removes the binding for an object in the Context with the given name.
    void
    unbindObject(String key)
    Removes the binding for an object in this Context with the given key.
    Collection<Object>
    values()
    Returns a (raw) collection of registered values in the current context.

    Methods inherited from class org.djutils.event.LocalEventProducer

    getEventListenerMap

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    Methods inherited from interface org.djutils.event.EventProducer

    addListener, addListener, addListener, addListener, fireEvent, fireEvent, fireEvent, fireTimedEvent, fireTimedEvent, fireTimedEvent, fireUnverifiedEvent, fireUnverifiedEvent, fireUnverifiedTimedEvent, fireUnverifiedTimedEvent, getEventListenerMap, getEventTypesWithListeners, getListenerReferences, hasListeners, numberOfListeners, removeAllListeners, removeAllListeners, removeListener

  • Field Details

  • Constructor Details

    • JvmContext

      public JvmContext(String atomicName)
      constructs a new root JvmContext.
      Parameters:
      atomicName - the name under which the root context will be registered

    • JvmContext

      public JvmContext(ContextInterface parent, String atomicName)
      Constructs a new JvmContext.
      Parameters:
      parent - the parent context
      atomicName - the name under which the context will be registered

  • Method Details

    • getAtomicName

      public String getAtomicName()
      Description copied from interface: ContextInterface
      Retrieves the atomic name of this context.
      Specified by:
      getAtomicName in interface ContextInterface
      Returns:
      the atomic name of this context

    • getParent

      public ContextInterface getParent()
      Description copied from interface: ContextInterface
      Retrieves the parent context for this context, or null when this is the root context.
      Specified by:
      getParent in interface ContextInterface
      Returns:
      parent context for this context, or null when this is the root context

    • getRootContext

      public ContextInterface getRootContext()
      Description copied from interface: ContextInterface
      Retrieves the root context for this context, or the current context when this is the root context.
      Specified by:
      getRootContext in interface ContextInterface
      Returns:
      the root context for this context

    • getAbsolutePath

      public String getAbsolutePath()
      Description copied from interface: ContextInterface
      Returns the absolute path for this context, or an empty string when this is the root context.
      Specified by:
      getAbsolutePath in interface ContextInterface
      Returns:
      the absolute path for this context, or an empty string when this is the root context

    • getObject

      public Object getObject(String key) throws NamingException
      Description copied from interface: ContextInterface
      Retrieves the named object from the Context. The key is not compound. Key cannot be empty or contain "/".
      Specified by:
      getObject in interface ContextInterface
      Parameters:
      key - the name of the object to look up; NOT a compound name
      Returns:
      the Context or Object indicated by the key
      Throws:
      NamingException - when key is the empty string or when key contains "/"
      NameNotFoundException - if the key does not exist in the current context

    • get

      public Object get(String name) throws NamingException
      Description copied from interface: ContextInterface
      Retrieves the named object from the Context. The name may be a compound name where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts must exist. When name is the empty String or "/", the current Context is returned.
      Specified by:
      get in interface ContextInterface
      Parameters:
      name - the name of the object to look up; may be a compound name
      Returns:
      the Context or Object indicated by the name
      Throws:
      NamingException - as a placeholder overarching exception
      NameNotFoundException - if an intermediate context or the reference does not exist

    • exists

      public boolean exists(String name) throws NamingException
      Description copied from interface: ContextInterface
      Indicates whether an object with the given name has been registered in the Context. The name may be a compound name where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts must exist. When name is the empty String or "/", the method returns true.
      Specified by:
      exists in interface ContextInterface
      Parameters:
      name - the name of the object to look up; may be a compound name
      Returns:
      whether an object with the given name has been registered
      Throws:
      NamingException - as a placeholder overarching exception
      NameNotFoundException - when an intermediate context does not exist

    • hasKey

      public boolean hasKey(String key) throws NamingException
      Description copied from interface: ContextInterface
      Indicates whether the key has been registered in the current Context. The name is not compound. When name is the empty String or "/", the method returns an exception.
      Specified by:
      hasKey in interface ContextInterface
      Parameters:
      key - the name of the object to look up; NOT compound
      Returns:
      whether an object with the given key has been registered in the current context
      Throws:
      NamingException - when key is the empty string or when key contains "/"

    • hasObject

      public boolean hasObject(Object object)
      Indicates whether the object has been registered (once or more) in the current Context. The object may be null.
      Specified by:
      hasObject in interface ContextInterface
      Parameters:
      object - the object to look up; mey be null
      Returns:
      whether an object with the given key has been registered once or more in the current context

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: ContextInterface
      Indicates whether the current context is empty.
      Specified by:
      isEmpty in interface ContextInterface
      Returns:
      whether the current context is empty

    • bindObject

      public void bindObject(String key, Object object) throws NamingException
      Description copied from interface: ContextInterface
      Binds an object into this Context using the key. The key is not compound. The key cannot be empty or "/". An OBJECT_ADDED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the object when a new binding has taken place.
      Specified by:
      bindObject in interface ContextInterface
      Parameters:
      key - the key under which the object will be stored; NOT a compound name
      object - the Context or Object to be stored into this Context using the given name; a null object is allowed
      Throws:
      NamingException - when key is the empty string or when key contains "/"
      NameAlreadyBoundException - if key is already bound to an object

    • bindObject

      public void bindObject(Object object) throws NamingException
      Description copied from interface: ContextInterface
      Binds an object into the Context using the toString() method of the object as the key. All "/" characters in the toString() result will be replaced by "#" characters. An OBJECT_ADDED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the object when a new binding has taken place.
      Specified by:
      bindObject in interface ContextInterface
      Parameters:
      object - the Context or Object to be stored into this Context using the toString() result as the key; a null object is not allowed
      Throws:
      NamingException - when the toString() of the object results in an empty string
      NameAlreadyBoundException - if key is already bound to an object

    • bind

      public void bind(String name, Object object) throws NamingException
      Description copied from interface: ContextInterface
      Binds an object into the Context using the name. The name may be a compound name where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts must already exist. The object will be registered using the terminal atomic reference in the deepest subcontext provided. Name cannot be empty or "/". An OBJECT_ADDED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the object when a new binding has taken place.
      Specified by:
      bind in interface ContextInterface
      Parameters:
      name - the name under which the object will be stored; may be a compound name with the terminal reference indicating the key under which the object will be stored
      object - the Context or Object to be stored into the given context; a null object is allowed
      Throws:
      NamingException - when the reference is "/" or empty
      NameAlreadyBoundException - if name is already bound to an object
      NameNotFoundException - when an intermediate context does not exist

    • unbindObject

      public void unbindObject(String key) throws NamingException
      Description copied from interface: ContextInterface
      Removes the binding for an object in this Context with the given key. The key is not compound. The key cannot be empty or "/". It is not a problem when there is no object registered with the given key. An OBJECT_REMOVED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the removed object when a binding has been removed.
      Specified by:
      unbindObject in interface ContextInterface
      Parameters:
      key - the key of the object that has to be removed; NOT a compound name
      Throws:
      NamingException - when key is the empty string or when key contains "/"

    • unbind

      public void unbind(String name) throws NamingException
      Description copied from interface: ContextInterface
      Removes the binding for an object in the Context with the given name. The name may be a compound name where parts are separated by separation strings indicating subcontexts. Name cannot be empty or "/". It is not a problem when there is no object registered with the given name. An OBJECT_REMOVED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the removed object when a binding has been removed.
      Specified by:
      unbind in interface ContextInterface
      Parameters:
      name - the name of the object that has to be removed; may be a compound name with the terminal reference indicating the key under which the object is stored
      Throws:
      NamingException - when the reference is "/" or empty
      NameNotFoundException - when an intermediate context does not exist

    • rebindObject

      public void rebindObject(String key, Object object) throws NamingException
      Description copied from interface: ContextInterface
      Replaces an object in this Context with the given key, or registers the object when a registration with the key does not exist yet. The key is not a compound name. Name cannot be empty or "/". An OBJECT_REMOVED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the removed object when a binding had to be removed, followed by an OBJECT_ADDED_EVENT containing an object array with a pointer to the context, the key, and the new object when a new binding has taken place.
      Specified by:
      rebindObject in interface ContextInterface
      Parameters:
      key - the key of the object to be replaced, or under which the object will be stored; NOT a compound name
      object - the Context or Object to be replaced or stored into this Context using the given name; a null object is allowed
      Throws:
      NamingException - when key is the empty string or when key contains "/"

    • rebind

      public void rebind(String name, Object object) throws NamingException
      Description copied from interface: ContextInterface
      Replaces an object in the Context with the given name, or registers the object when a registration with the name does not exist yet. The name may be a compound name where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts must already exist. The object will be (re)registered using the terminal atomic reference in the deepest subcontext provided. Name cannot be empty or "/". An OBJECT_REMOVED_EVENT is fired containing an object array with a pointer to the context, the relative key, and the removed object when a binding had to be removed, followed by an OBJECT_ADDED_EVENT containing an object array with a pointer to the context, the key, and the new object when a new binding has taken place.
      Specified by:
      rebind in interface ContextInterface
      Parameters:
      name - the name of the object to be replaced, or under which the object will be stored; may be a compound name with the terminal reference indicating the key under which the object will be stored
      object - the Context or Object to be replaced or stored into this Context using the given name; a null object is allowed
      Throws:
      NamingException - when the reference is "/" or empty
      NameNotFoundException - when an intermediate context does not exist

    • rename

      public void rename(String oldName, String newName) throws NamingException
      Description copied from interface: ContextInterface
      Replaces the name under which an object has been registered in the Context. Both names are relative to the current Context, and may be compound names where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts of the new name must already exist. The object will be deregistered under the old name, and reregistered using the terminal atomic reference in the deepest subcontext of the newName. Nether the oldName, nor the newName can be empty or "/". An OBJECT_REMOVED_EVENT is fired containing an object array with a pointer to the old context, the old relative key, and the object when a binding had to be removed, followed by an OBJECT_ADDED_EVENT containing an object array with a pointer to the new context, the new relative key, and the object when a new binding has taken place. When the new name is illegal or occupied, the object will not be renamed.
      Specified by:
      rename in interface ContextInterface
      Parameters:
      oldName - the (compound) name of the object to be moved to a new location
      newName - the (compound) name with the terminal reference indicating where the object will be stored
      Throws:
      NamingException - when the reference of oldName or newName is "/" or empty
      NameNotFoundException - when an intermediate context of oldName or newName does not exist, or when there is no registration at the oldName reference
      NameAlreadyBoundException - if newName is already bound to an object

    • createSubcontext

      public ContextInterface createSubcontext(String name) throws NamingException
      Description copied from interface: ContextInterface
      Creates and binds a new context into the current Context using the name. The name may be a compound name where parts are separated by separation strings indicating subcontexts. All intermediate subcontexts that do not yet exist, will be created. The new context will be registered using the terminal atomic reference in the deepest subcontext provided. Name cannot be empty or "/". On success, OBJECT_ADDED_EVENTs are fired for the created context and each new intermediate context, containing an object array with an object array with a pointer to the embedding context, the local key in the embedding context, and the newly created (intermediate) context.
      Specified by:
      createSubcontext in interface ContextInterface
      Parameters:
      name - the name under which the new context will be stored; may be a compound name with the terminal reference indicating the key under which the new context will be stored
      Returns:
      a pointer to the newly created subcontext
      Throws:
      NamingException - when the terminal reference is "/" or empty
      NameNotFoundException - when an intermediate context does not exist
      NameAlreadyBoundException - if name is already bound to an object or context

    • destroySubcontext

      public void destroySubcontext(String name) throws NamingException
      Description copied from interface: ContextInterface
      Removes the binding for an existing, empty subcontext with the given name, and recursively unbinds all objects and contexts in the context indicated by the name. The name may be a compound name where parts are separated by separation strings indicating subcontexts. Name cannot be empty or "/". A context has to be registered with the given name. For all removed objects and contexts, OBJECT_REMOVED_EVENT events are fired containing an object array with a pointer to the context from which content has been removed, the key of the binding that has been removed, and the removed object. The OBJECT_REMOVED_EVENT events are fired in depth-first order.
      Specified by:
      destroySubcontext in interface ContextInterface
      Parameters:
      name - the name of the object that has to be removed; may be a compound name with the terminal reference indicating the key under which the object is stored
      Throws:
      NamingException - when the reference is "/" or empty
      NotContextException - if the name is bound but does not name a context
      NameNotFoundException - when an intermediate context does not exist, or when no object is registered with the terminating atomic reference

    • lookupAndBuild

      protected ContextInterface lookupAndBuild(String name) throws NamingException
      Take a (compound) name such as "sub1/sub2/key" or "key" or "/sub/key" and lookup and/or create all intermediate contexts as well as the final sub-context of the path.
      Parameters:
      name - the (possibly compound) name
      Returns:
      the context, possibly built new
      Throws:
      NamingException - as a placeholder overarching exception
      NameNotFoundException - when an intermediate context does not exist
      NullPointerException - when name is null

    • destroy

      protected void destroy(ContextInterface context) throws NamingException
      Recursively unbind and destroy all keys and subcontexts from the given context, leaving it empty. All removals will fire an OBJECT_REMOVED event, depth first.
      Parameters:
      context - the context to empty
      Throws:
      NamingException - on tree inconsistencies

    • keySet

      public Set<String> keySet()
      Description copied from interface: ContextInterface
      Returns a set of registered keys in the current context.
      Specified by:
      keySet in interface ContextInterface
      Returns:
      a set of registered keys in the current context

    • values

      public Collection<Object> values()
      Description copied from interface: ContextInterface
      Returns a (raw) collection of registered values in the current context.
      Specified by:
      values in interface ContextInterface
      Returns:
      a raw set of registered objects in the current context

    • bindings

      public Map<String,Object> bindings()
      Description copied from interface: ContextInterface
      Returns a (raw) map of bindings in the current context, mapping the name on the registered objects. Both regular objects and subcontexts are returned. Mappings to null objects can exist.
      Specified by:
      bindings in interface ContextInterface
      Returns:
      a map of registered names and their bound (possibly null) object in the current context

    • fireObjectChangedEventValue

      public void fireObjectChangedEventValue(Object object) throws NameNotFoundException, NullPointerException, NamingException
      Description copied from interface: ContextInterface
      Fire an OBJECT_CHANGED_EVENT for an object within the current context. Look up if the the object exists using the toString() method of the object as the key. All "/" characters in the toString() result will be replaced by "#" characters. When the object does not exist directly in the context, a NameNotFoundException is thrown.
      Specified by:
      fireObjectChangedEventValue in interface ContextInterface
      Parameters:
      object - the object that has changed and for which an event should be fired
      Throws:
      NameNotFoundException - when no object is registered with object.toString() as the key
      NullPointerException - when object is null
      NamingException - on general error in the method, e.g., a problem with remote connections

    • fireObjectChangedEventKey

      public void fireObjectChangedEventKey(String key) throws NameNotFoundException, NullPointerException, NamingException
      Description copied from interface: ContextInterface
      Fire an OBJECT_CHANGED_EVENT for an object with the given key in the current context. If the the key does not exist directly in the context, a NameNotFoundException is thrown. The key should not be the empty String or contain "/" characters.
      Specified by:
      fireObjectChangedEventKey in interface ContextInterface
      Parameters:
      key - the key within the context of the object that has changed and for which an event should be fired
      Throws:
      NameNotFoundException - when no object is registered with the key in the given context
      NullPointerException - when key is null
      NamingException - when key is the empty string or when key contains "/", or on a general error in the method, e.g., a problem with remote connections

    • checkCircular

      public void checkCircular(Object newObject) throws NamingException
      Description copied from interface: ContextInterface
      Check whether a circular reference would occur when the object would be inserted into the current context. Insertion potentially causes a problem when the object to be inserted is a Context.
      Specified by:
      checkCircular in interface ContextInterface
      Parameters:
      newObject - the object to be inserted
      Throws:
      NamingException - when a circular reference would occur

    • close

      public void close() throws NamingException
      Description copied from interface: ContextInterface
      Closes the context and removes all content from the context. No events will be fired that the content of the context has been removed. Some contexts, such as the FileContext could have to be really closed as well.
      Specified by:
      close in interface ContextInterface
      Throws:
      NamingException - when a problem occurs during closing (e.g., of a FileContext)

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • toString

      public String toString(boolean verbose)
      Description copied from interface: ContextInterface
      Return a String with the hierarchical content of the Context in case verbose is true; otherwise return the atomic name.
      Specified by:
      toString in interface ContextInterface
      Parameters:
      verbose - whether the information is exhaustive or very brief
      Returns:
      formatted content of the context when verbose is true; otherwise the atomic name

    • lookup

      protected JvmContext.ContextName lookup(String name) throws NamingException
      Take a (compound) name such as "sub1/sub2/key" or "key" or "/sub/key" and lookup the final sub-context of the path, and store it in the ContextName. Store the key String in the ContextName without checking whether it exists.
      Parameters:
      name - the (possibly compound) name
      Returns:
      a ContextName combination string the subcontext and final reference name
      Throws:
      NamingException - as a placeholder overarching exception
      NameNotFoundException - when an intermediate context does not exist
      NullPointerException - when name is null