com.yworks.yfiles.graph

Class LookupDecorator<TDecoratedType,TInterface>

java.lang.Object

com.yworks.yfiles.graph.LookupDecorator<TDecoratedType,TInterface>

Type Parameters:

TDecoratedType - The type of the instances whose ILookup.lookup(Class) behavior should be modified.

TInterface - The interface or type that clients will use during the ILookup.lookup(Class) call. Note that this is normally an interface and not the implementation of the interface since client code will use the interface for the query.

public final class LookupDecorator<TDecoratedType,TInterface>
extends Object

A convenience class that simplifies using an ILookupDecorator.

This class provides convenience methods that help in performing common tasks related to decorating the ILookup.lookup(Class) method for a certain TDecoratedType.

See Also:

ILookup, GraphDecorator, LookupExtensions

Constructor Summary

Constructors

Constructor and Description
LookupDecorator(Class<TDecoratedType> decoratedType, Class<TInterface> interfaceType, ILookupDecorator decorator, boolean decorateNulls, boolean nullIsFallback) Initializes a new instance of the LookupDecorator class.

Method Summary

Modifier and Type	Method and Description
IContextLookupChainLink	addChainLink(IContextLookupChainLink lookup) Simple helper method that tries to add the provided chain link to the Decorator.
ILookupDecorator	getDecorator() Gets the ILookupDecorator instance that is used.
IContextLookupChainLink	hideImplementation() Amends the lookup chain for all TDecoratedType items matching a predicate to return null if TInterface is queried during the ILookup.lookup(Class).
IContextLookupChainLink	hideImplementation(Predicate<TDecoratedType> predicate) Amends the lookup chain for all TDecoratedType items matching a predicate to return null if TInterface is queried during the ILookup.lookup(Class).
boolean	isDecoratingNullsEnabled() Gets a value indicating whether wrapping implementations will wrap null values from the rest of the lookup chain or those values will simply be returned instead.
boolean	isNullFallback() Gets a value indicating whether a null result value of the methods setImplementation(Predicate, java.lang.Object) and setFactory(Function) should be interpreted as taking the fallback value, or actually return null.
void	setDecoratingNullsEnabled(boolean value) Sets a value indicating whether wrapping implementations will wrap null values from the rest of the lookup chain or those values will simply be returned instead.
IContextLookupChainLink	setFactory(Function<TDecoratedType,TInterface> factory) Amends the lookup chain for all TDecoratedType items, so that factory is used to create a TInterface instance if TInterface is queried during the ILookup.lookup(Class).
IContextLookupChainLink	setFactory(Predicate<TDecoratedType> predicate, Function<TDecoratedType,TInterface> factory) Amends the lookup chain for items matching a predicate with a factory that creates a TInterface instance if TInterface is queried during the ILookup.lookup(Class).
IContextLookupChainLink	setImplementation(Predicate<TDecoratedType> predicate, TInterface implementation) Amends the lookup chain for all items matching a predicate with a fixed TInterface implementation if TInterface is queried on an item's ILookup.lookup(Class).
IContextLookupChainLink	setImplementation(TDecoratedType item, TInterface implementation) Amends the lookup chain for a single item with a fixed TInterface implementation if TInterface is queried on the item's ILookup.lookup(Class).
IContextLookupChainLink	setImplementation(TInterface implementation) Amends the lookup chain, so that implementation is always returned if TInterface is queried on an item's ILookup.lookup(Class).
IContextLookupChainLink	setImplementationWrapper(BiFunction<TDecoratedType,TInterface,TInterface> factory) Amends the lookup chain for all items with a factory callback that wraps the underlying implementation if TInterface is queried during the ILookup.lookup(Class).
IContextLookupChainLink	setImplementationWrapper(Predicate<TDecoratedType> predicate, BiFunction<TDecoratedType,TInterface,TInterface> factory) Amends the lookup chain for all items matching a predicate with a factory callback that wraps the underlying implementation if TInterface is queried during the ILookup.lookup(Class).
void	setNullFallback(boolean value) Sets a value indicating whether a null result value of the methods setImplementation(Predicate, java.lang.Object) and setFactory(Function) should be interpreted as taking the fallback value, or actually return null.

Methods inherited from class java.lang.Object

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

Constructor Detail

LookupDecorator

public LookupDecorator(Class<TDecoratedType> decoratedType,
                       Class<TInterface> interfaceType,
                       ILookupDecorator decorator,
                       boolean decorateNulls,
                       boolean nullIsFallback)

Initializes a new instance of the LookupDecorator class.

Parameters:

decoratedType - The type of the instances whose ILookup.lookup(Class) behavior should be modified.

interfaceType - The interface or type that clients will use during the ILookup.lookup(Class) call. Note that this is normally an interface and not the implementation of the interface since client code will use the interface for the query.

decorator - The decorator instance that will be used to extend the Lookup mechanism.

decorateNulls - The initial value of the DecoratingNullsEnabled property.

nullIsFallback - The initial value of the NullFallback property.

Method Detail

addChainLink

public final IContextLookupChainLink addChainLink(IContextLookupChainLink lookup)

Simple helper method that tries to add the provided chain link to the Decorator.

Parameters:

lookup - The link to add.

Returns:

The lookup that has been added to the Decorator as a result of this call, or null if the decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

getDecorator

public final ILookupDecorator getDecorator()

Gets the ILookupDecorator instance that is used.

This can be null. In this case all methods of this class do nothing.

Returns:

The Decorator.

hideImplementation

public final IContextLookupChainLink hideImplementation()

Amends the lookup chain for all TDecoratedType items matching a predicate to return null if TInterface is queried during the ILookup.lookup(Class).

This can be used to temporarily or permanently disable a certain behavior for all items. To do this only for items matching a predicate, use hideImplementation(Predicate) instead.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

hideImplementation

public final IContextLookupChainLink hideImplementation(Predicate<TDecoratedType> predicate)

Amends the lookup chain for all TDecoratedType items matching a predicate to return null if TInterface is queried during the ILookup.lookup(Class).

This can be used to temporarily or permanently disable a certain behavior for all items. To do this only for items matching a predicate, use hideImplementation(Predicate) instead.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

predicate - The predicate that determines for which items the implementation shall be hidden.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

isDecoratingNullsEnabled

public final boolean isDecoratingNullsEnabled()

Gets a value indicating whether wrapping implementations will wrap null values from the rest of the lookup chain or those values will simply be returned instead.

If this is true, then the SetImplementationWrapper methods will not wrap null values from the rest of the lookup chain and the result of the call to ILookup.lookup(Class) will simply be null. If this is false, the wrapper will get null as the implementation to wrap and should handle this accordingly.

Returns:

The DecoratingNullsEnabled.

See Also:

setDecoratingNullsEnabled(boolean)

isNullFallback

public final boolean isNullFallback()

Gets a value indicating whether a null result value of the methods setImplementation(Predicate, java.lang.Object) and setFactory(Function) should be interpreted as taking the fallback value, or actually return null.

If this is true, then null values returned from the implementation or factory set with setImplementation(java.lang.Object) or setFactory(Function) are not returned, but rather interpreted as a hint to query the rest of the lookup chain. If this is false, then null values are returned as is.

Returns:

The NullFallback.

See Also:

setNullFallback(boolean)

setDecoratingNullsEnabled

public final void setDecoratingNullsEnabled(boolean value)

Sets a value indicating whether wrapping implementations will wrap null values from the rest of the lookup chain or those values will simply be returned instead.

If this is true, then the SetImplementationWrapper methods will not wrap null values from the rest of the lookup chain and the result of the call to ILookup.lookup(Class) will simply be null. If this is false, the wrapper will get null as the implementation to wrap and should handle this accordingly.

Parameters:

value - The DecoratingNullsEnabled to set.

See Also:

isDecoratingNullsEnabled()

setFactory

public final IContextLookupChainLink setFactory(Function<TDecoratedType,TInterface> factory)

Amends the lookup chain for all TDecoratedType items, so that factory is used to create a TInterface instance if TInterface is queried during the ILookup.lookup(Class).

This can be used to modify the lookup of all items where the returned instance either depends on the item or uses it in some way.

To only adjust the lookup of items matching a predicate in this manner, use setFactory(Predicate, Function) instead. To adjust the lookup of a single item, use setImplementation(java.lang.Object).

Note that depending on the value of the NullFallback property a null return value from the factory will be either returned directly, or interpreted as a hint to return a fallback value which is obtained by querying the remainder of the lookup chain.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

factory - The factory that is queried to create the result.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions, isNullFallback()

setFactory

public final IContextLookupChainLink setFactory(Predicate<TDecoratedType> predicate,
                                                Function<TDecoratedType,TInterface> factory)

Amends the lookup chain for items matching a predicate with a factory that creates a TInterface instance if TInterface is queried during the ILookup.lookup(Class).

This can be used to modify the lookup of all items matching a certain predicate where the returned instance either depends on the item or uses it in some way.

To adjust the lookup of all items in this manner, use setFactory(Function) instead. To adjust the lookup of a single item, use setImplementation(java.lang.Object).

Note that depending on the value of the NullFallback property a null return value from the factory will be either returned directly, or interpreted as a hint to return a fallback value which is obtained by querying the remainder of the lookup chain.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

predicate - The predicate that determines for which items the factory shall be called.

factory - The factory that is queried to create the result.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions, isNullFallback()

setImplementation

public final IContextLookupChainLink setImplementation(Predicate<TDecoratedType> predicate,
                                                       TInterface implementation)

Amends the lookup chain for all items matching a predicate with a fixed TInterface implementation if TInterface is queried on an item's ILookup.lookup(Class).

This can be used to modify the lookup of all items matching a certain predicate in the same way.

To adjust the lookup of only a single item, use setImplementation(java.lang.Object, java.lang.Object) instead. To adjust the lookup of all items, use setImplementation(java.lang.Object).

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

predicate - A predicate that determines which items are affected.

implementation - The implementation to return if the predicate matches and TInterface is queried.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

setImplementation

public final IContextLookupChainLink setImplementation(TDecoratedType item,
                                                       TInterface implementation)

Amends the lookup chain for a single item with a fixed TInterface implementation if TInterface is queried on the item's ILookup.lookup(Class).

This can be used to modify the lookup of a single item only.

To adjust the lookup of all items matching a predicate, use setImplementation(Predicate, java.lang.Object) instead. To adjust the lookup of all items, use setImplementation(java.lang.Object).

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

item - The item for which the implementation shall be returned.

implementation - The implementation to return if item is queried for TInterface.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

setImplementation

public final IContextLookupChainLink setImplementation(TInterface implementation)

Amends the lookup chain, so that implementation is always returned if TInterface is queried on an item's ILookup.lookup(Class).

This can be used to modify the lookup of all items in the same way.

To adjust the lookup of only a single item, use setImplementation(java.lang.Object, java.lang.Object) instead. To adjust the lookup of all items matching a certain predicate, use setImplementation(Predicate, java.lang.Object).

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

implementation - The implementation to return unconditionally.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

setImplementationWrapper

public final IContextLookupChainLink setImplementationWrapper(BiFunction<TDecoratedType,TInterface,TInterface> factory)

Amends the lookup chain for all items with a factory callback that wraps the underlying implementation if TInterface is queried during the ILookup.lookup(Class).

This can be used to modify the lookup of all items matching where the factory implementation may delegate to the wrapped implementation in certain cases.

To adjust the lookup in this manner only for items matching a predicate, use setImplementationWrapper(Predicate, BiFunction) instead. To adjust the lookup of a single item, use setImplementation(java.lang.Object).

Note that depending on the value of the DecoratingNullsEnabled property, the factory will not not be called to decorate null results.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

factory - The factory that will be passed the underlying implementation and that is queried to create the result.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

setImplementationWrapper

public final IContextLookupChainLink setImplementationWrapper(Predicate<TDecoratedType> predicate,
                                                              BiFunction<TDecoratedType,TInterface,TInterface> factory)

Amends the lookup chain for all items matching a predicate with a factory callback that wraps the underlying implementation if TInterface is queried during the ILookup.lookup(Class).

This can be used to modify the lookup of all items matching a certain predicate where the factory implementation may delegate to the wrapped implementation in certain cases.

To adjust the lookup for all items in this manner, use setImplementationWrapper(BiFunction) instead. To adjust the lookup of a single item, use setImplementation(java.lang.Object).

Note that depending on the value of the DecoratingNullsEnabled property, the factory will not not be called to decorate null results.

The effects of this method call can be undone by passing the return value to ILookupDecorator.removeLookup(Class, IContextLookupChainLink).

Parameters:

predicate - The predicate that determines for which items the wrapping shall be performed.

factory - The factory that will be passed the underlying implementation and that is queried to create the result.

Returns:

An IContextLookupChainLink that has been added to the Decorator as a result of this call, or null if decoration was unsuccessful.

See Also:

ILookupDecorator.addLookup(Class, IContextLookupChainLink), LookupExtensions

setNullFallback

public final void setNullFallback(boolean value)

Sets a value indicating whether a null result value of the methods setImplementation(Predicate, java.lang.Object) and setFactory(Function) should be interpreted as taking the fallback value, or actually return null.

If this is true, then null values returned from the implementation or factory set with setImplementation(java.lang.Object) or setFactory(Function) are not returned, but rather interpreted as a hint to query the rest of the lookup chain. If this is false, then null values are returned as is.

Parameters:

value - The NullFallback to set.

See Also:

isNullFallback()