Package org.apache.velocity.context
Class AbstractContext
- java.lang.Object
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- org.apache.velocity.context.InternalContextBase
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- org.apache.velocity.context.AbstractContext
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- All Implemented Interfaces:
Context
,InternalEventContext
,InternalHousekeepingContext
- Direct Known Subclasses:
VelocityContext
public abstract class AbstractContext extends InternalContextBase 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.
- Version:
- $Id: AbstractContext.java 732250 2009-01-07 07:37:10Z byron $
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Field Summary
Fields Modifier and Type Field Description private Context
innerContext
the chained Context if any
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Constructor Summary
Constructors Constructor Description AbstractContext()
default CTORAbstractContext(Context inner)
Chaining constructor accepts a Context argument.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description boolean
containsKey(java.lang.Object key)
Indicates whether the specified key is in the context.java.lang.Object
get(java.lang.String key)
Gets the value corresponding to the provided key from the context.Context
getChainedContext()
returns innerContext if one is chainedjava.lang.Object[]
getKeys()
Get all the keys for the values in the contextabstract boolean
internalContainsKey(java.lang.Object key)
Implement to determine if a key is in the storage.abstract java.lang.Object
internalGet(java.lang.String key)
Implement to return a value from the context storage.abstract java.lang.Object[]
internalGetKeys()
Implement to return an object array of key strings from your storage.abstract java.lang.Object
internalPut(java.lang.String key, java.lang.Object value)
Implement to put a value into the context storage.abstract java.lang.Object
internalRemove(java.lang.Object key)
I mplement to remove an item from your storage.java.lang.Object
put(java.lang.String key, java.lang.Object value)
Adds a name/value pair to the context.java.lang.Object
remove(java.lang.Object key)
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 Detail
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innerContext
private Context innerContext
the chained Context if any
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Constructor Detail
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AbstractContext
public AbstractContext()
default CTOR
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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
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Method Detail
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internalGet
public abstract java.lang.Object internalGet(java.lang.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
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internalPut
public abstract java.lang.Object internalPut(java.lang.String key, java.lang.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 valuevalue
- value to be associated with the key- Returns:
- previously stored value if exists, or null
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internalContainsKey
public abstract boolean internalContainsKey(java.lang.Object 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 existance- Returns:
- true if found, false if not
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internalGetKeys
public abstract java.lang.Object[] 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
public abstract java.lang.Object internalRemove(java.lang.Object key)
I mplement 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
public java.lang.Object put(java.lang.String key, java.lang.Object value)
Adds a name/value pair to the context.
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get
public java.lang.Object get(java.lang.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.
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containsKey
public boolean containsKey(java.lang.Object key)
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
public java.lang.Object[] getKeys()
Get all the keys for the values in the context
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remove
public java.lang.Object remove(java.lang.Object key)
Removes the value associated with the specified key from the context.
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getChainedContext
public Context getChainedContext()
returns innerContext if one is chained- Returns:
- Context if chained,
null
if not
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