com.massa.mrules.accessor

Class MPropertyAccessor

java.lang.Object

com.massa.mrules.base.AbstractMRulesObject

com.massa.mrules.addon.AbstractAddon

com.massa.mrules.accessor.AbstractReadAccessor

com.massa.mrules.accessor.MPropertyAccessor

All Implemented Interfaces:

IAccessor, IAccessorValueHandler, IReadAccessor, IReadAccessor.Standalone, IReadWriteAccessor, IWriteAccessor, IAddon, IMRulesObject, Outable, Serializable, Cloneable

@PersistantProperty(property="property") @PersistantProperty(property="source") @PersistantProperty(property="optimizeMultiRead",defaultValue="true")
public class MPropertyAccessor
extends AbstractReadAccessor
implements IReadAccessor.Standalone, IReadWriteAccessor, IAccessorValueHandler

Allows to retrieve value from an object and to cast it depending on target. if the object is issued from an accessor instead of the context, the compilation will make less verifications, and problems might appear at runtime. Moreover, the property accessor can only be used as read only if there is an source accessor and it's iterable. The standard source for property access is the context read base for the "get" method, and the context write base for the "set" method. Some exceptions :

• if the "source" accessor is not null, it's data will be the base for access.
• if the property name starts with "$", it designs a variable.
• if the property name starts with "#", it designs a global variable, in which case the "source" accessor will be ignored.

The synthax is very common and is an extention of the Apache commons-beanutils language :

• property1.property2: Equivalent to Java call context.getReadBase().getProperty1().getProperty2()
• mapProperty.propertyName: Equivalent to Java call context.getReadBase().getMapProperty().get("propertyName")
• mapProperty("propertyName"): Equivalent to Java call context.getReadBase().getMapProperty().get("propertyName")
• mapProperty('propertyName'): Still the same.
• Please note that mapProperty.propertyName1.propertyName2 is not equivalent to mapProperty("propertyName1.propertyName2")
• mapProperty(subProperty1.subProperty2): Equivalent to Java call context.getReadBase().getMapProperty().get(context.getReadBase().getSubProperty1().getSubProperty2())
• mapProperty($var.subProperty): to use a local variable
• mapProperty(#VAR.subProperty): to use a global variable
• Indexed property (Arrays and Lists) can be used in the same way that maps, but with brackets: "[" and "]".

An option allows to optimize multiple read of a same field by caching result. The caching will be deactivated for accessing variables. If a source accessor is specified, this optimization won't be effective.
The cache might also partially be deactivated with the specific feature "property-access", which would disable caching of reflection calls results but would not disable caching for parent addons.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.massa.mrules.accessor.IReadAccessor

IReadAccessor.Standalone

Field Summary

Fields

Modifier and Type	Field and Description
static String	PROPERTY_FEATURE The value of this constant ("property-access") allows to disable caching of property access results, meaning that the value returned by the accessed method will not be cached, but the value returned by the property accessor might be cached to avoid multiple casts of the same values.
static String	PROPERTY_ID

Constructor Summary

Constructors

Constructor and Description
MPropertyAccessor()
MPropertyAccessor(IReadAccessor source) Property has to be set later.
MPropertyAccessor(IReadAccessor source, String property)
MPropertyAccessor(String property)

Method Summary

Modifier and Type	Method and Description
MPropertyAccessor	clone() Clones the Addon.
<G,C extends Collection<G>> void	compileCollection(ICompilationContext ctxt, Class<C> expectedType, Class<G> expectedGenericType) Implementation to handle case when expected result is a Collection.
void	compileReadWrite(ICompilationContext ctxt, boolean forReadTarget) Compiles this accessor to get or set a value.
void	compileValue(ICompilationContext ctxt, Class<?> expectedType) Implementation to handle case when expected result is a single value.
void	compileWrite(ICompilationContext ctxt) Compiles this accessor to set a value.
boolean	equals(Object o)
Object	get(IExecutionContext ctxt, boolean instantiateAll) Gets the value of the target.
CostInfo	getEstimatedReadCost(ICompilationContext ctxt) Estimates the reading complexity, to allow callers to optimize calls.
Class<?>	getGenericCollectionType(IContext ctxt) Returns the Generic type, if value is a collection or an array, evaluated : at compilation time for standard compilation at runtime for light compilation and execution phase or null if the type can't be resolved or value is not a collection.
Class<?>[]	getGenericTypes(IContext ctxt) By default, creates a 1 cell array with IAccessor.getGenericCollectionType(IContext) return value if any, or null if no value.
String	getImplementationId() Unique addon implementation ID.
Integer	getInternalCacheIdentifier() Returns null by default.
String	getProperty()
protected PropertyCompiler2	getPropertyCompiler(ICompilationContext ctxt) Allows to override usage of PropertyCompiler2 for this Accessor.
IReadAccessor	getSource()
Class<?>	getType(IContext ctxt) Returns the value's class, evaluated : at compilation time for standard compilation at runtime for light compilation or null if the type can't be resolved.
Object	handleValue(IExecutionContext ctxt, Object srcValue) Called for each value of the iterated element.
Object	handleValue(IExecutionContext ctxt, Object srcValue, boolean instantiateAll)
int	hashCode()
protected Object	internalGet(IExecutionContext ctxt) Specific addon implementation must be here.
boolean	isCacheUsed() Returns false by default.
boolean	isGlobalVar()
boolean	isInternalCacheIdentifierNeeded() This method allows to tell the engine if a cache identifier is needed.
boolean	isLocalVar()
boolean	isOptimizeMultiRead()
boolean	isShouldIterate() If this iterator is dedicated to iterate over values, then it should be precised.
boolean	isVar()
void	resetCachedData(IExecutionContext ctxt) Does nothing.
Object	set(IExecutionContext ctxt, IReadAccessor accessor) Sets the value.
Object	set(IExecutionContext ctxt, Object obj) Sets the value.
void	setInternalCacheIdentifier(Integer internalIdentifier) Stores nothing.
void	setOptimizeMultiRead(boolean optimizeMultiRead)
void	setProperty(String property)
void	setSource(IReadAccessor source)
void	toString(OuterWithLevel outer) Method used to send String representation of the current object to the OuterWithLevel.
boolean	wasRegistered(ICompilationContext ctxt, IAddon parent, AddonInfo info) Convenience method, which does nothing.

Methods inherited from class com.massa.mrules.accessor.AbstractReadAccessor

castToExpected, compileRead, compileRead, compileRead, compileRead, get, isConstantValue, isShouldBeWrappedToConstantValue, isShouldNotCache

Methods inherited from class com.massa.mrules.addon.AbstractAddon

optimize, toString

Methods inherited from class com.massa.mrules.base.AbstractMRulesObject

getDebugInfo, getDescription, getName, setDebugInfo, setDescription, setName

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.massa.mrules.accessor.IReadAccessor

compileRead, compileRead, compileRead, compileRead, get, isConstantValue, isShouldBeWrappedToConstantValue

Methods inherited from interface com.massa.mrules.addon.IAddon

optimize

Methods inherited from interface com.massa.mrules.base.IMRulesObject

getDebugInfo, getDescription, getName, setDebugInfo, setDescription, setName

Field Detail

PROPERTY_ID

public static final String PROPERTY_ID

See Also:

Constant Field Values

PROPERTY_FEATURE

public static final String PROPERTY_FEATURE

The value of this constant ("property-access") allows to disable caching of property access results, meaning that the value returned by the accessed method will not be cached, but the value returned by the property accessor might be cached to avoid multiple casts of the same values.

See Also:

ICacheActivationResolver.isCacheEnabled(String), Constant Field Values

Constructor Detail

MPropertyAccessor

public MPropertyAccessor()

MPropertyAccessor

public MPropertyAccessor(String property)

MPropertyAccessor

public MPropertyAccessor(IReadAccessor source)

Property has to be set later.

MPropertyAccessor

public MPropertyAccessor(IReadAccessor source,
                         String property)

Method Detail

compileValue

public void compileValue(ICompilationContext ctxt,
                         Class<?> expectedType)
                  throws MRuleValidationException

Description copied from class: AbstractReadAccessor

Implementation to handle case when expected result is a single value.

Specified by:

compileValue in class AbstractReadAccessor

Throws:

MRuleValidationException

compileCollection

public <G,C extends Collection<G>> void compileCollection(ICompilationContext ctxt,
                                                          Class<C> expectedType,
                                                          Class<G> expectedGenericType)
                                                   throws MRuleValidationException

Description copied from class: AbstractReadAccessor

Implementation to handle case when expected result is a Collection.

Specified by:

compileCollection in class AbstractReadAccessor

Throws:

MRuleValidationException

compileWrite

public void compileWrite(ICompilationContext ctxt)
                  throws MRuleValidationException

Description copied from interface: IWriteAccessor

Compiles this accessor to set a value.

Specified by:

compileWrite in interface IWriteAccessor

Throws:

MRuleValidationException - if validation problem detected.

compileReadWrite

public void compileReadWrite(ICompilationContext ctxt,
                             boolean forReadTarget)
                      throws MRuleValidationException

Description copied from interface: IReadWriteAccessor

Compiles this accessor to get or set a value. The default target is the context read or write base depending on the "forReadTarget" parameter value.
The contract of the "compileRead(*)" and "compileWrite(*)" methods is globally updated :

• compileRead will always target the read base.
• compileWrite will always target the write base.

Specified by:

compileReadWrite in interface IReadWriteAccessor

forReadTarget - To choose between read or write base for compilation and execution.

Throws:

MRuleValidationException - if validation problem detected.

getPropertyCompiler

protected PropertyCompiler2 getPropertyCompiler(ICompilationContext ctxt)

Allows to override usage of PropertyCompiler2 for this Accessor.

wasRegistered

public boolean wasRegistered(ICompilationContext ctxt,
                             IAddon parent,
                             AddonInfo info)
                      throws MRuleValidationException

Description copied from class: AbstractAddon

Convenience method, which does nothing. All implementing classes may override to perform internal operations, starting with a "super" call to keep compatibility with future versions.

Specified by:

wasRegistered in interface IAddon

Overrides:

wasRegistered in class AbstractAddon

parent - Parent from which this instance of addon was registered.

info - Addon info for the currently registered addon

Returns:

false

Throws:

MRuleValidationException

getEstimatedReadCost

public CostInfo getEstimatedReadCost(ICompilationContext ctxt)
                              throws MRuleValidationException

Description copied from interface: IReadAccessor

Estimates the reading complexity, to allow callers to optimize calls. Calls to this method should be done on a compiled accessor, so that all information is available to compute complexity.
Calls to non-compiled instance may return non-accurate results.

Specified by:

getEstimatedReadCost in interface IReadAccessor

Parameters:

ctxt - Compilation context.

Throws:

MRuleValidationException - if validation problem detected.

internalGet

protected Object internalGet(IExecutionContext ctxt)
                      throws MAccessorException

Description copied from class: AbstractReadAccessor

Specific addon implementation must be here.

Specified by:

internalGet in class AbstractReadAccessor

Throws:

MAccessorException

get

public Object get(IExecutionContext ctxt,
                  boolean instantiateAll)
           throws MAccessorException

Description copied from interface: IReadWriteAccessor

Gets the value of the target. Automatic cast might be done according to specified expected types. If requested, all nested null properties and the final one will be instantiated, if possible. If impossible, an exception is raised.

Specified by:

get in interface IReadWriteAccessor

Throws:

MAccessorException

handleValue

public Object handleValue(IExecutionContext ctxt,
                          Object srcValue)
                   throws MAccessorException

Description copied from interface: IAccessorValueHandler

Called for each value of the iterated element.

Specified by:

handleValue in interface IAccessorValueHandler

Throws:

MAccessorException

handleValue

public Object handleValue(IExecutionContext ctxt,
                          Object srcValue,
                          boolean instantiateAll)
                   throws MAccessorException

Throws:

MAccessorException

set

public Object set(IExecutionContext ctxt,
                  IReadAccessor accessor)
           throws MAccessorException

Description copied from interface: IWriteAccessor

Sets the value. Automatic cast might be done according to the target type.

Specified by:

set in interface IWriteAccessor

Returns:

Value set.

Throws:

MAccessorException

set

public Object set(IExecutionContext ctxt,
                  Object obj)
           throws MAccessorException

Description copied from interface: IWriteAccessor

Sets the value. Automatic cast might be done according to the target type.

Specified by:

set in interface IWriteAccessor

Returns:

Value set.

Throws:

MAccessorException

getType

public Class<?> getType(IContext ctxt)
                 throws MAccessorException

Description copied from interface: IAccessor

Returns the value's class, evaluated :

• at compilation time for standard compilation
• at runtime for light compilation

or null if the type can't be resolved.

Specified by:

getType in interface IAccessor

Throws:

MAccessorException

getGenericCollectionType

public Class<?> getGenericCollectionType(IContext ctxt)
                                  throws MAccessorException

Description copied from interface: IAccessor

Returns the Generic type, if value is a collection or an array, evaluated :

• at compilation time for standard compilation
• at runtime for light compilation and execution phase

or null if the type can't be resolved or value is not a collection.

Specified by:

getGenericCollectionType in interface IAccessor

Throws:

MAccessorException

getGenericTypes

public Class<?>[] getGenericTypes(IContext ctxt)
                           throws MAccessorException

Description copied from class: AbstractReadAccessor

By default, creates a 1 cell array with IAccessor.getGenericCollectionType(IContext) return value if any, or null if no value.

Specified by:

getGenericTypes in interface IAccessor

Overrides:

getGenericTypes in class AbstractReadAccessor

Throws:

MAccessorException

isShouldIterate

public boolean isShouldIterate()

Description copied from interface: IReadAccessor

If this iterator is dedicated to iterate over values, then it should be precised. In this case, the "get" method should return an Iterator, of instances of "getType".
Non-read only accessors should not be iterable. BUT it's not mandatory. In this particular case, the "set" method should be described precisely ...
Please not that returned Iterators should not support the "remove" method.
They also should use MRuleInternalRuntimeException if Exception must be thrown.
This method is not dependent on the compilation process. it can be called before and will return the correct result.

Specified by:

isShouldIterate in interface IReadAccessor

getImplementationId

public String getImplementationId()

Description copied from interface: IAddon

Unique addon implementation ID. In case of conflict, an Class Initialization error will be raised.

Specified by:

getImplementationId in interface IAddon

clone

public MPropertyAccessor clone()

Description copied from interface: IAddon

Clones the Addon.
The general contract is that the clone of a compiled Addon is still compiled.

Specified by:

clone in interface IAccessor

Specified by:

clone in interface IReadAccessor

Specified by:

clone in interface IReadWriteAccessor

Specified by:

clone in interface IWriteAccessor

Specified by:

clone in interface IAddon

Specified by:

clone in interface IMRulesObject

Overrides:

clone in class AbstractReadAccessor

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public void toString(OuterWithLevel outer)
              throws IOException

Description copied from interface: Outable

Method used to send String representation of the current object to the OuterWithLevel.

Specified by:

toString in interface Outable

Throws:

IOException

getProperty

public String getProperty()

setProperty

public final void setProperty(String property)

getSource

public IReadAccessor getSource()

setSource

public void setSource(IReadAccessor source)

isOptimizeMultiRead

public boolean isOptimizeMultiRead()

setOptimizeMultiRead

public void setOptimizeMultiRead(boolean optimizeMultiRead)

resetCachedData

public void resetCachedData(IExecutionContext ctxt)

Description copied from class: AbstractAddon

Does nothing.

Specified by:

resetCachedData in interface IAddon

Overrides:

resetCachedData in class AbstractAddon

isCacheUsed

public boolean isCacheUsed()

Description copied from class: AbstractAddon

Returns false by default.

Specified by:

isCacheUsed in interface IAddon

Overrides:

isCacheUsed in class AbstractAddon

isVar

public boolean isVar()

isLocalVar

public boolean isLocalVar()

isGlobalVar

public boolean isGlobalVar()

setInternalCacheIdentifier

public final void setInternalCacheIdentifier(Integer internalIdentifier)

Description copied from class: AbstractAddon

Stores nothing.

Specified by:

setInternalCacheIdentifier in interface IAddon

Overrides:

setInternalCacheIdentifier in class AbstractAddon

Parameters:

internalIdentifier - Internal identifier

See Also:

IAddon.getInternalCacheIdentifier()

getInternalCacheIdentifier

public final Integer getInternalCacheIdentifier()

Description copied from class: AbstractAddon

Returns null by default.

Specified by:

getInternalCacheIdentifier in interface IAddon

Overrides:

getInternalCacheIdentifier in class AbstractAddon

Returns:

Internal identifier

See Also:

IAddon.setInternalCacheIdentifier(Integer)

isInternalCacheIdentifierNeeded

public boolean isInternalCacheIdentifierNeeded()

Description copied from class: AbstractAddon

This method allows to tell the engine if a cache identifier is needed. If not, the Addon will not be able to use internal execution cache.

Specified by:

isInternalCacheIdentifierNeeded in interface IAddon

Overrides:

isInternalCacheIdentifierNeeded in class AbstractAddon

Returns:

Internal identifier

See Also:

AbstractAddon.setInternalCacheIdentifier(Integer)