Package org.apache.velocity.context

Class AbstractContext

java.lang.Object
org.apache.velocity.context.AbstractContext
All Implemented Interfaces:
Context, InternalEventContext
Direct Known Subclasses:
DBContext, TreeMapContext, VelocityContext
public abstract class AbstractContext extends Object implements Context
This class is the abstract base class for all conventional Velocity Context implementations. Simply extend this class and implement the abstract routines that access your preferred storage method. Takes care of context chaining. Also handles / enforces policy on null keys and values :
  • Null keys and values are accepted and basically dropped.
  • If you place an object into the context with a null key, it will be ignored and logged.
  • If you try to place a null into the context with any key, it will be dropped and logged.
The default implementation of this for application use is org.apache.velocity.VelocityContext. All thanks to Fedor for the chaining idea.
Version:
$Id$
Author:
Geir Magnusson Jr., Fedor Karpelevitch, Jason van Zyl

  • Constructor Details

    • AbstractContext

      public AbstractContext()
      default CTOR

    • AbstractContext

      public AbstractContext(Context inner)
      Chaining constructor accepts a Context argument. It will relay get() operations into this Context in the even the 'local' get() returns null.
      Parameters:
      inner - context to be chained

  • Method Details

    • internalGet

      public abstract Object internalGet(String key)
      Implement to return a value from the context storage.

      The implementation of this method is required for proper operation of a Context implementation in general Velocity use.
      Parameters:
      key - key whose associated value is to be returned
      Returns:
      object stored in the context

    • internalPut

      public abstract Object internalPut(String key, Object value)
      Implement to put a value into the context storage.

      The implementation of this method is required for proper operation of a Context implementation in general Velocity use.
      Parameters:
      key - key with which to associate the value
      value - value to be associated with the key
      Returns:
      previously stored value if exists, or null

    • internalContainsKey

      public abstract boolean internalContainsKey(String key)
      Implement to determine if a key is in the storage.

      Currently, this method is not used internally by the Velocity engine.
      Parameters:
      key - key to test for existence
      Returns:
      true if found, false if not

    • internalGetKeys

      public abstract String[] internalGetKeys()
      Implement to return an object array of key strings from your storage.

      Currently, this method is not used internally by the Velocity engine.
      Returns:
      array of keys

    • internalRemove

      public abstract Object internalRemove(String key)
      Implement to remove an item from your storage.

      Currently, this method is not used internally by the Velocity engine.
      Parameters:
      key - key to remove
      Returns:
      object removed if exists, else null

    • put

      public Object put(String key, Object value)
      Adds a name/value pair to the context.
      Specified by:
      put in interface Context
      Parameters:
      key - The name to key the provided value with.
      value - The corresponding value.
      Returns:
      Object that was replaced in the the Context if applicable or null if not.

    • get

      public Object get(String key)
      Gets the value corresponding to the provided key from the context. Supports the chaining context mechanism. If the 'local' context doesn't have the value, we try to get it from the chained context.
      Specified by:
      get in interface Context
      Parameters:
      key - The name of the desired value.
      Returns:
      The value corresponding to the provided key or null if the key param is null.

    • containsKey

      public boolean containsKey(String key)
      Indicates whether the specified key is in the context. Provided for debugging purposes.
      Specified by:
      containsKey in interface Context
      Parameters:
      key - The key to look for.
      Returns:
      true if the key is in the context, false if not.

    • getKeys

      public String[] getKeys()
      Get all the keys for the values in the context
      Specified by:
      getKeys in interface Context
      Returns:
      Object[] of keys in the Context. Does not return keys in chained context.

    • remove

      public Object remove(String key)
      Removes the value associated with the specified key from the context.
      Specified by:
      remove in interface Context
      Parameters:
      key - The name of the value to remove.
      Returns:
      The value that the key was mapped to, or null if unmapped.

    • getChainedContext

      public Context getChainedContext()
      returns innerContext if one is chained
      Returns:
      Context if chained, null if not

    • pushCurrentTemplateName

      public void pushCurrentTemplateName(String s)
      set the current template name on top of stack
      Parameters:
      s - current template name

    • popCurrentTemplateName

      public void popCurrentTemplateName()
      remove the current template name from stack

    • getCurrentTemplateName

      public String getCurrentTemplateName()
      get the current template name
      Returns:
      String current template name

    • getTemplateNameStack

      public String[] getTemplateNameStack()
      get the current template name stack
      Returns:
      String[] with the template name stack contents.

    • pushCurrentMacroName

      public void pushCurrentMacroName(String s)
      set the current macro name on top of stack
      Parameters:
      s - current macro name

    • popCurrentMacroName

      public void popCurrentMacroName()
      remove the current macro name from stack

    • getCurrentMacroName

      public String getCurrentMacroName()
      get the current macro name
      Returns:
      String current macro name

    • getCurrentMacroCallDepth

      public int getCurrentMacroCallDepth()
      get the current macro call depth
      Returns:
      int current macro call depth

    • getMacroNameStack

      public String[] getMacroNameStack()
      get the current macro name stack
      Returns:
      String[] with the macro name stack contents.

    • icacheGet

      public IntrospectionCacheData icacheGet(Object key)
      returns an IntrospectionCache Data (@see IntrospectionCacheData) object if exists for the key
      Parameters:
      key - key to find in cache
      Returns:
      cache object

    • icachePut

      public void icachePut(Object key, IntrospectionCacheData o)
      places an IntrospectionCache Data (@see IntrospectionCacheData) element in the cache for specified key
      Parameters:
      key - key
      o - IntrospectionCacheData object to place in cache

    • setCurrentResource

      public void setCurrentResource(Resource r)
      See Also:
      • InternalHousekeepingContext.setCurrentResource(org.apache.velocity.runtime.resource.Resource)

    • getCurrentResource

      public Resource getCurrentResource()
      See Also:
      • InternalHousekeepingContext.getCurrentResource()

    • setMacroLibraries

      public void setMacroLibraries(List<Template> macroLibraries)
      See Also:
      • InternalHousekeepingContext.setMacroLibraries(List)

    • getMacroLibraries

      public List<Template> getMacroLibraries()
      See Also:
      • InternalHousekeepingContext.getMacroLibraries()

    • attachEventCartridge

      public EventCartridge attachEventCartridge(EventCartridge ec)
      Specified by:
      attachEventCartridge in interface InternalEventContext
      Parameters:
      ec -
      Returns:
      The old EventCartridge.
      See Also:

    • getEventCartridge

      public EventCartridge getEventCartridge()
      Specified by:
      getEventCartridge in interface InternalEventContext
      Returns:
      The current EventCartridge.
      See Also: