AbstractContext (Apache Velocity 2.3 API)

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 Summary

Constructors
Constructor and Description

AbstractContext()
default CTOR

AbstractContext(Context inner)
Chaining constructor accepts a Context argument.

Constructors
Constructor and Description
`AbstractContext()` default CTOR
`AbstractContext(Context inner)` Chaining constructor accepts a Context argument.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`EventCartridge`	`attachEventCartridge(EventCartridge ec)`
`boolean`	`containsKey(String key)` Indicates whether the specified key is in the context.
`Object`	`get(String key)` Gets the value corresponding to the provided key from the context.
`Context`	`getChainedContext()` returns innerContext if one is chained
`int`	`getCurrentMacroCallDepth()` get the current macro call depth
`String`	`getCurrentMacroName()` get the current macro name
`Resource`	`getCurrentResource()` temporary fix to enable #include() to figure out current encoding.
`String`	`getCurrentTemplateName()` get the current template name
`EventCartridge`	`getEventCartridge()`
`String[]`	`getKeys()` Get all the keys for the values in the context
`List<Template>`	`getMacroLibraries()` Get the macro library list for the current template.
`String[]`	`getMacroNameStack()` get the current macro name stack
`String[]`	`getTemplateNameStack()` get the current template name stack
`IntrospectionCacheData`	`icacheGet(Object key)` returns an IntrospectionCache Data (@see IntrospectionCacheData) object if exists for the key
`void`	`icachePut(Object key, IntrospectionCacheData o)` places an IntrospectionCache Data (@see IntrospectionCacheData) element in the cache for specified key
`abstract boolean`	`internalContainsKey(String key)` Implement to determine if a key is in the storage.
`abstract Object`	`internalGet(String key)` Implement to return a value from the context storage.
`abstract String[]`	`internalGetKeys()` Implement to return an object array of key strings from your storage.
`abstract Object`	`internalPut(String key, Object value)` Implement to put a value into the context storage.
`abstract Object`	`internalRemove(String key)` Implement to remove an item from your storage.
`void`	`popCurrentMacroName()` remove the current macro name from stack
`void`	`popCurrentTemplateName()` remove the current template name from stack
`void`	`pushCurrentMacroName(String s)` set the current macro name on top of stack
`void`	`pushCurrentTemplateName(String s)` set the current template name on top of stack
`Object`	`put(String key, Object value)` Adds a name/value pair to the context.
`Object`	`remove(String key)` Removes the value associated with the specified key from the context.
`void`	`setCurrentResource(Resource r)`
`void`	`setMacroLibraries(List<Template> macroLibraries)` Set the macro library list for the current template.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - 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 Detail
  - 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()
```
    temporary fix to enable #include() to figure out current encoding.
    
    Returns:
    
    The current resource.
    
    See Also:
    
    InternalHousekeepingContext.getCurrentResource()
  - setMacroLibraries
```
public void setMacroLibraries(List<Template> macroLibraries)
```
    Set the macro library list for the current template.
    
    Parameters:
    
    macroLibraries - list of macro libraries to set
    
    See Also:
    
    InternalHousekeepingContext.setMacroLibraries(List)
  - getMacroLibraries
```
public List<Template> getMacroLibraries()
```
    Get the macro library list for the current template.
    
    Returns:
    
    List of macro library names
    
    See Also:
    
    InternalHousekeepingContext.getMacroLibraries()
  - attachEventCartridge
```
public EventCartridge attachEventCartridge(EventCartridge ec)
```
    Specified by:
    
    attachEventCartridge in interface InternalEventContext
    
    Returns:
    
    The old EventCartridge.
    
    See Also:
    
    InternalEventContext.attachEventCartridge(org.apache.velocity.app.event.EventCartridge)
  - getEventCartridge
```
public EventCartridge getEventCartridge()
```
    Specified by:
    
    getEventCartridge in interface InternalEventContext
    
    Returns:
    
    The current EventCartridge.
    
    See Also:
    
    InternalEventContext.getEventCartridge()

Class AbstractContext

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

AbstractContext

AbstractContext

Method Detail

internalGet

internalPut

internalContainsKey

internalGetKeys

internalRemove

put

get

containsKey

getKeys

remove

getChainedContext

pushCurrentTemplateName

popCurrentTemplateName

getCurrentTemplateName

getTemplateNameStack

pushCurrentMacroName

popCurrentMacroName

getCurrentMacroName

getCurrentMacroCallDepth

getMacroNameStack

icacheGet

icachePut

setCurrentResource

getCurrentResource

setMacroLibraries

getMacroLibraries

attachEventCartridge

getEventCartridge