Package org.springframework.beans.propertyeditors

Class CustomCollectionEditor

java.lang.Object

java.beans.PropertyEditorSupport

org.springframework.beans.propertyeditors.CustomCollectionEditor

All Implemented Interfaces:

PropertyEditor

public class CustomCollectionEditor
extends PropertyEditorSupport

Property editor for Collections, converting any source Collection to a given target Collection type.

By default registered for Set, SortedSet and List, to automatically convert any given Collection to one of those target types if the type does not match the target property.

Since:

1.1.3

Author:

Juergen Hoeller

See Also:

• Collection
• Set
• SortedSet
• List

Constructor Summary

Constructors

Constructor	Description
CustomCollectionEditor(Class<? extends Collection> collectionType)	Create a new CustomCollectionEditor for the given target type, keeping an incoming null as-is.
CustomCollectionEditor(Class<? extends Collection> collectionType, boolean nullAsEmptyCollection)	Create a new CustomCollectionEditor for the given target type.

Method Summary

Modifier and Type	Method	Description
protected boolean	alwaysCreateNewCollection()	Return whether to always create a new Collection, even if the type of the passed-in Collection already matches.
protected Object	convertElement(Object element)	Hook to convert each encountered Collection/array element.
protected Collection<Object>	createCollection(Class<? extends Collection> collectionType, int initialCapacity)	Create a Collection of the given type, with the given initial capacity (if supported by the Collection 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 Collection with a single element.
void	setValue(Object value)	Convert the given value to a Collection 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 Details

CustomCollectionEditor

public CustomCollectionEditor(Class<? extends Collection> collectionType)

Create a new CustomCollectionEditor for the given target type, keeping an incoming null as-is.

Parameters:

collectionType - the target type, which needs to be a sub-interface of Collection or a concrete Collection class

See Also:

• Collection
• ArrayList
• TreeSet
• LinkedHashSet

CustomCollectionEditor

public CustomCollectionEditor(Class<? extends Collection> collectionType,
 boolean nullAsEmptyCollection)

Create a new CustomCollectionEditor 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 Collection type or an array, it will be converted to a default implementation of the given Collection type. If the value is anything else, a target Collection with that single value will be created.

The default Collection implementations are: ArrayList for List, TreeSet for SortedSet, and LinkedHashSet for Set.

Parameters:

collectionType - the target type, which needs to be a sub-interface of Collection or a concrete Collection class

nullAsEmptyCollection - whether to convert an incoming null value to an empty Collection (of the appropriate type)

See Also:

• Collection
• ArrayList
• TreeSet
• LinkedHashSet

Method Details

setAsText

public void setAsText(String text)
               throws IllegalArgumentException

Convert the given text value to a Collection with a single element.

Specified by:

setAsText in interface PropertyEditor

Overrides:

setAsText in class PropertyEditorSupport

Throws:

IllegalArgumentException

setValue

public void setValue(@Nullable
 Object value)

Convert the given value to a Collection of the target type.

Specified by:

setValue in interface PropertyEditor

Overrides:

setValue in class PropertyEditorSupport

createCollection

protected Collection<Object> createCollection(Class<? extends Collection> collectionType,
 int initialCapacity)

Create a Collection of the given type, with the given initial capacity (if supported by the Collection type).

Parameters:

collectionType - a sub-interface of Collection

initialCapacity - the initial capacity

Returns:

the new Collection instance

alwaysCreateNewCollection

protected boolean alwaysCreateNewCollection()

Return whether to always create a new Collection, even if the type of the passed-in Collection already matches.

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

See Also:

• convertElement(java.lang.Object)

convertElement

protected Object convertElement(Object element)

Hook to convert each encountered Collection/array element. The default implementation simply returns the passed-in element as-is.

Can be overridden to perform conversion of certain elements, for example String to Integer if a String array comes in and should be converted to a Set of Integer objects.

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

Parameters:

element - the source element

Returns:

the element to be used in the target Collection

See Also:

• alwaysCreateNewCollection()

getAsText

@Nullable
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