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CustomMapEditor (Spring Framework API 2.0) - Spring Framework 2.0.5 API 文档英文版

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org.springframework.beans.propertyeditors
Class CustomMapEditor

java.lang.Object
  extended by java.beans.PropertyEditorSupport
      extended by org.springframework.beans.propertyeditors.CustomMapEditor
All Implemented Interfaces:
PropertyEditor

public class CustomMapEditor
extends PropertyEditorSupport

Property editor for Maps, converting any source Map to a given target Map type.

Since:
2.0.1
Author:
Juergen Hoeller
See Also:
Map, SortedMap

Constructor Summary
CustomMapEditor(Class mapType)
          Create a new CustomMapEditor for the given target type, keeping an incoming null as-is.
CustomMapEditor(Class mapType, boolean nullAsEmptyMap)
          Create a new CustomMapEditor for the given target type.
 
Method Summary
protected  boolean alwaysCreateNewMap()
          Return whether to always create a new Map, even if the type of the passed-in Map already matches.
protected  Object convertKey(Object key)
          Hook to convert each encountered Map key.
protected  Object convertValue(Object value)
          Hook to convert each encountered Map value.
protected  Map createMap(Class mapType, int initialCapacity)
          Create a Map of the given type, with the given initial capacity (if supported by the Map type).
 String getAsText()
          This implementation returns null to indicate that there is no appropriate text representation.
 void setAsText(String text)
          Convert the given text value to a Map with a single element.
 void setValue(Object value)
          Convert the given value to a Map of the target type.
 
Methods inherited from class java.beans.PropertyEditorSupport
addPropertyChangeListener, firePropertyChange, getCustomEditor, getJavaInitializationString, getSource, getTags, getValue, isPaintable, paintValue, removePropertyChangeListener, setSource, supportsCustomEditor
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CustomMapEditor

public CustomMapEditor(Class mapType)
Create a new CustomMapEditor for the given target type, keeping an incoming null as-is.

Parameters:
mapType - the target type, which needs to be a sub-interface of Map or a concrete Map class
See Also:
Map, HashMap, TreeMap, CollectionFactory.createLinkedMapIfPossible(int)

CustomMapEditor

public CustomMapEditor(Class mapType,
                       boolean nullAsEmptyMap)
Create a new CustomMapEditor for the given target type.

If the incoming value is of the given type, it will be used as-is. If it is a different Map type or an array, it will be converted to a default implementation of the given Map type. If the value is anything else, a target Map with that single value will be created.

The default Map implementations are: ArrayList for List, TreeSet for SortedSet, and LinkedHashSet or HashSet for Set.

Parameters:
mapType - the target type, which needs to be a sub-interface of Map or a concrete Map class
nullAsEmptyMap - ap whether to convert an incoming null value to an empty Map (of the appropriate type)
See Also:
Map, HashMap, TreeMap, CollectionFactory.createLinkedMapIfPossible(int)
Method Detail

setAsText

public void setAsText(String text)
               throws IllegalArgumentException
Convert the given text value to a Map with a single element.

Specified by:
setAsText in interface PropertyEditor
Overrides:
setAsText in class PropertyEditorSupport
Throws:
IllegalArgumentException

setValue

public void setValue(Object value)
Convert the given value to a Map of the target type.

Specified by:
setValue in interface PropertyEditor
Overrides:
setValue in class PropertyEditorSupport

createMap

protected Map createMap(Class mapType,
                        int initialCapacity)
Create a Map of the given type, with the given initial capacity (if supported by the Map type).

Parameters:
mapType - a sub-interface of Map
initialCapacity - the initial capacity
Returns:
the new Map instance

alwaysCreateNewMap

protected boolean alwaysCreateNewMap()
Return whether to always create a new Map, even if the type of the passed-in Map already matches.

Default is "false"; can be overridden to enforce creation of a new Map, for example to convert elements in any case.

See Also:
convertKey(java.lang.Object), convertValue(java.lang.Object)

convertKey

protected Object convertKey(Object key)
Hook to convert each encountered Map key. The default implementation simply returns the passed-in key as-is.

Can be overridden to perform conversion of certain keys, for example from String to Integer.

Only called if actually creating a new Map! This is by default not the case if the type of the passed-in Map already matches. Override alwaysCreateNewMap() to enforce creating a new Map in every case.

Parameters:
key - the source key
Returns:
the key to be used in the target Map
See Also:
alwaysCreateNewMap()

convertValue

protected Object convertValue(Object value)
Hook to convert each encountered Map value. The default implementation simply returns the passed-in value as-is.

Can be overridden to perform conversion of certain values, for example from String to Integer.

Only called if actually creating a new Map! This is by default not the case if the type of the passed-in Map already matches. Override alwaysCreateNewMap() to enforce creating a new Map in every case.

Parameters:
value - the source value
Returns:
the value to be used in the target Map
See Also:
alwaysCreateNewMap()

getAsText

public String getAsText()
This implementation returns null to indicate that there is no appropriate text representation.

Specified by:
getAsText in interface PropertyEditor
Overrides:
getAsText in class PropertyEditorSupport

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