Package org.apache.velocity.context
Class AbstractContext
java.lang.Object
org.apache.velocity.context.InternalContextBase
org.apache.velocity.context.AbstractContext
- All Implemented Interfaces:
Context
,InternalEventContext
,InternalHousekeepingContext
- Direct Known Subclasses:
VelocityContext
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.
- Version:
- $Id$
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptiondefault CTORAbstractContext
(Context inner) Chaining constructor accepts a Context argument. -
Method Summary
Modifier and TypeMethodDescriptionboolean
containsKey
(String key) Indicates whether the specified key is in the context.Gets the value corresponding to the provided key from the context.returns innerContext if one is chainedString[]
getKeys()
Get all the keys for the values in the contextabstract boolean
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[]
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.Adds a name/value pair to the context.Removes the value associated with the specified key from the context.Methods inherited from class org.apache.velocity.context.InternalContextBase
attachEventCartridge, getCurrentMacroCallDepth, getCurrentMacroName, getCurrentResource, getCurrentTemplateName, getEventCartridge, getMacroLibraries, getMacroNameStack, getTemplateNameStack, icacheGet, icachePut, popCurrentMacroName, popCurrentTemplateName, pushCurrentMacroName, pushCurrentTemplateName, setCurrentResource, setMacroLibraries
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Field Details
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innerContext
the chained Context if any
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Constructor Details
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AbstractContext
public AbstractContext()default CTOR -
AbstractContext
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
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Method Details
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internalGet
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
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internalPut
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 valuevalue
- value to be associated with the key- Returns:
- previously stored value if exists, or null
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internalContainsKey
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
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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
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internalRemove
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
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put
Adds a name/value pair to the context. -
get
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. -
containsKey
Indicates whether the specified key is in the context. Provided for debugging purposes.- Specified by:
containsKey
in interfaceContext
- Parameters:
key
- The key to look for.- Returns:
- true if the key is in the context, false if not.
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getKeys
Get all the keys for the values in the context -
remove
Removes the value associated with the specified key from the context. -
getChainedContext
returns innerContext if one is chained- Returns:
- Context if chained,
null
if not
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