net.wotonomy.control.internal
Class Surrogate

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap
          net.wotonomy.foundation.NSDictionary
              net.wotonomy.foundation.NSMutableDictionary
                  net.wotonomy.control.internal.Surrogate

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map, net.wotonomy.foundation.NSKeyValueCoding

public class Surrogate
extends net.wotonomy.foundation.NSMutableDictionary

A Surrogate is a special object that can be used in a display group when you wish to emulate other objects or modify their behaviors. Because it is a Map, it makes use of Introspector's ability to treat keys in a map as if they were properties to implement the following features.

• By default, Surrogate works like a Map, and reading and writing properties to a Surrogate gets and puts values in the Map.
• If one or more delegate objects are specified, property keys that do not exist in the map are read from and written to the delegate object.
• If a default value is specified, that value will be returned for all property reads that do not exist in the map or in the delegate object. (Subsequent writes to those properties will create a key in the map and then subsequent reads will read not read the default object.)
• Subclasses can override the get(Object) method to further customize the behavior of a Surrogate.

Author:

michael@mpowers.net

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface net.wotonomy.foundation.NSKeyValueCoding

net.wotonomy.foundation.NSKeyValueCoding.DefaultImplementation, net.wotonomy.foundation.NSKeyValueCoding.Null, net.wotonomy.foundation.NSKeyValueCoding.Utility

Field Summary

protected java.lang.Object	defaultValue
protected java.lang.Object[]	delegates

Fields inherited from class net.wotonomy.foundation.NSDictionary

EmptyDictionary

Fields inherited from interface net.wotonomy.foundation.NSKeyValueCoding

NullValue

Constructor Summary

Surrogate()
Default constructor with no delegate object and no default value.

Surrogate(java.lang.Object aDefault)
Constructor specifying a default value.

Surrogate(java.lang.Object[] aDelegateArray)
Constructor specifying a delegate object.

Surrogate(java.lang.Object[] aDelegateArray, java.lang.Object aDefault)
Constructor specifying a delegate object and a default value.

Method Summary

java.lang.Object	directGet(java.lang.Object aKey) Called by get to retrieve a value from the internal map.
java.lang.Object	directPut(java.lang.Object aKey, java.lang.Object aValue) Called by put to retrieve a value from the internal map.
boolean	equals(java.lang.Object anObject) Overridden to compare by reference.
java.lang.Object	get(java.lang.Object aKey) Overridden to consult each delegate before checking the internal list of keys.
java.lang.Object	getDefaultValue() Returns the current default value, or null if no default exists.
java.lang.Object	getDelegate() Returns the first delegate object, or null if no delegates exist.
java.lang.Object[]	getDelegates() Returns the list of delegates in the order in which they are consulted.
java.lang.Object	put(java.lang.Object aKey, java.lang.Object aValue) Overridden to attempt to write each delegate, writing to only the first successful delegate, before storing the value in the internal map.
void	setDefaultValue(java.lang.Object aDefault) Sets the default value.
void	setDelegate(java.lang.Object aDelegate) Sets the delegate object list to contain only the specified object.
void	setDelegates(java.lang.Object[] aDelegateArray) Sets the list of delegates in the order in which they will be consulted.

Methods inherited from class net.wotonomy.foundation.NSMutableDictionary

addEntriesFromDictionary, removeAllObjects, removeObjectForKey, removeObjectsForKeys, setDictionary, setObjectForKey

Methods inherited from class net.wotonomy.foundation.NSDictionary

allKeys, allKeysForObject, allValues, count, handleQueryWithUnboundKey, handleTakeValueForUnboundKey, isEqualToDictionary, keyEnumerator, objectEnumerator, objectForKey, objectsForKeys, storedValueForKey, takeStoredValueForKey, takeValueForKey, toString, unableToSetNullForKey, validateTakeValueForKeyPath, valueForKey

Methods inherited from class java.util.HashMap

clear, clone, containsKey, containsValue, entrySet, isEmpty, keySet, putAll, remove, size, values

Methods inherited from class java.util.AbstractMap

hashCode

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

hashCode

Field Detail

delegates

protected java.lang.Object[] delegates

defaultValue

protected java.lang.Object defaultValue

Constructor Detail

Surrogate

public Surrogate()

Default constructor with no delegate object and no default value.

Surrogate

public Surrogate(java.lang.Object[] aDelegateArray)

Constructor specifying a delegate object.

Surrogate

public Surrogate(java.lang.Object aDefault)

Constructor specifying a default value.

Surrogate

public Surrogate(java.lang.Object[] aDelegateArray,
                 java.lang.Object aDefault)

Constructor specifying a delegate object and a default value.

Method Detail

getDelegate

public java.lang.Object getDelegate()

Returns the first delegate object, or null if no delegates exist.

setDelegate

public void setDelegate(java.lang.Object aDelegate)

Sets the delegate object list to contain only the specified object.

getDelegates

public java.lang.Object[] getDelegates()

Returns the list of delegates in the order in which they are consulted.

setDelegates

public void setDelegates(java.lang.Object[] aDelegateArray)

Sets the list of delegates in the order in which they will be consulted.

getDefaultValue

public java.lang.Object getDefaultValue()

Returns the current default value, or null if no default exists.

setDefaultValue

public void setDefaultValue(java.lang.Object aDefault)

Sets the default value.

directGet

public java.lang.Object directGet(java.lang.Object aKey)

Called by get to retrieve a value from the internal map. This implementation simply calls super.get().

directPut

public java.lang.Object directPut(java.lang.Object aKey,
                                  java.lang.Object aValue)

Called by put to retrieve a value from the internal map. This implementation simply calls super.put().

get

public java.lang.Object get(java.lang.Object aKey)

Overridden to consult each delegate before checking the internal list of keys. No matching key is found, returns the default object, or null if no default object exists.

Specified by:

get in interface java.util.Map

Overrides:

get in class java.util.HashMap

put

public java.lang.Object put(java.lang.Object aKey,
                            java.lang.Object aValue)

Overridden to attempt to write each delegate, writing to only the first successful delegate, before storing the value in the internal map.

Specified by:

put in interface java.util.Map

Overrides:

put in class java.util.HashMap

equals

public boolean equals(java.lang.Object anObject)

Overridden to compare by reference.

Specified by:

equals in interface java.util.Map

Overrides:

equals in class java.util.AbstractMap