org.vedantatree.expressionoasis

Class ExpressionContext

java.lang.Object

org.vedantatree.expressionoasis.ExpressionContext

Direct Known Subclasses:

CustomExpressionContext

public class ExpressionContext
extends Object

Object of this class carry the contextual information for expressions during expression evaluation process. Like it can have information for variable providers, function providers and other properties. This is a thread safe object, hence can be used with multiple expression evaluation process at the same time in multiple threads. Care needs to be taken for the properties if threads are changing them at the same time. It may results in unexpected result.

Version:

1.0 Modified constructor to register function providers that are configured in XML file rather than hardcoded function providers, so that function providers can be added and removed as required by a given application without needing to recompile., 1.1

Author:

Mohit Gupta, Parmod Kamboj, Kris Marwood

Constructor Summary

Constructors

Constructor and Description
ExpressionContext() Constructor

Method Summary

Modifier and Type	Method and Description
void	addFunctionProvider(FunctionProvider functionProvider) Adds function provider to the expression context.
void	addVariableProvider(VariableProvider variableProvider) Adds variable provider to the expression context.
void	addVariableProvider(VariableProvider variableProvider, String providerName)
void	clearVariableProviders()
Object	getContextProperty(String propertyName) Returns the value for a property.
Collection<FunctionProvider>	getFunctionProviders() Gets the collection of function providers.
VariableProvider	getVariableProvider(String providerName)
Collection<VariableProvider>	getVariableProviders() Gets the collection of variable providers.
void	reset() Resets the expression context.
void	setContextProperty(String propertyName, Object propertyValue) Sets the value for any context property.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExpressionContext

public ExpressionContext()
                  throws ExpressionEngineException

Constructor

Throws:

ExpressionEngineException

Method Detail

addVariableProvider

public void addVariableProvider(VariableProvider variableProvider,
                                String providerName)

addVariableProvider

public void addVariableProvider(VariableProvider variableProvider)

Adds variable provider to the expression context.

Parameters:

variableProvider - the variable provider to add

addFunctionProvider

public void addFunctionProvider(FunctionProvider functionProvider)
                         throws ExpressionEngineException

Adds function provider to the expression context.

Parameters:

functionProvider - the function provider to add

Throws:

ExpressionEngineException

getFunctionProviders

public Collection<FunctionProvider> getFunctionProviders()

Gets the collection of function providers. It is an unmodifiable list.

Returns:

Returns the functionProviders.

getVariableProviders

public Collection<VariableProvider> getVariableProviders()

Gets the collection of variable providers. It is an unmodifiable list.

Returns:

Returns the variableProviders

getVariableProvider

public VariableProvider getVariableProvider(String providerName)

setContextProperty

public void setContextProperty(String propertyName,
                               Object propertyValue)

Sets the value for any context property.

Parameters:

propertyName - the name of property

propertyValue - the value of property

getContextProperty

public Object getContextProperty(String propertyName)

Returns the value for a property.

Parameters:

propertyName - the name of property

Returns:

the value corresponding to the property. null if no property exists in expression context

clearVariableProviders

public void clearVariableProviders()

reset

public void reset()

Resets the expression context. Cleans all the states of this expression context for further reuse.