org.apache.commons.collections

Class BeanMap

public class BeanMap extends AbstractMap implements Cloneable

Deprecated: Identical class now available in commons-beanutils (full jar version). This version is due to be removed in collections v4.0.

An implementation of Map for JavaBeans which uses introspection to get and put properties in the bean.

If an exception occurs during attempts to get or set a property then the property is considered non existent in the Map

Since: Commons Collections 1.0

Version: $Revision: 158697 $ $Date: 2005-03-22 23:47:45 +0000 (Tue, 22 Mar 2005) $

Author: James Strachan Stephen Colebourne Dimiter Dimitrov

Nested Class Summary
protected static classBeanMap.MyMapEntry
Map entry used by BeanMap.
Field Summary
static HashMapdefaultTransformers
Maps primitive Class types to transformers.
static Object[]NULL_ARGUMENTS
An empty array.
Constructor Summary
BeanMap()
Constructs a new empty BeanMap.
BeanMap(Object bean)
Constructs a new BeanMap that operates on the specified bean.
Method Summary
voidclear()
This method reinitializes the bean map to have default values for the bean's properties.
Objectclone()
Clone this bean map using the following process:
  • If there is no underlying bean, return a cloned BeanMap without a bean.
booleancontainsKey(Object name)
Returns true if the bean defines a property with the given name.
booleancontainsValue(Object value)
Returns true if the bean defines a property whose current value is the given object.
protected ObjectconvertType(Class newType, Object value)
Converts the given value to the given type.
protected Object[]createWriteMethodArguments(Method method, Object value)
Creates an array of parameters to pass to the given mutator method.
IteratorentryIterator()
Convenience method for getting an iterator over the entries.
SetentrySet()
Gets a Set of MapEntry objects that are the mappings for this BeanMap.
protected voidfirePropertyChange(Object key, Object oldValue, Object newValue)
Called during a successful put operation.
Objectget(Object name)
Returns the value of the bean's property with the given name.
ObjectgetBean()
Returns the bean currently being operated on.
MethodgetReadMethod(String name)
Returns the accessor for the property with the given name.
protected MethodgetReadMethod(Object name)
Returns the accessor for the property with the given name.
ClassgetType(String name)
Returns the type of the property with the given name.
protected TransformergetTypeTransformer(Class aType)
Returns a transformer for the given primitive type.
MethodgetWriteMethod(String name)
Returns the mutator for the property with the given name.
protected MethodgetWriteMethod(Object name)
Returns the mutator for the property with the given name.
IteratorkeyIterator()
Convenience method for getting an iterator over the keys.
SetkeySet()
Get the keys for this BeanMap.
protected voidlogInfo(Exception ex)
Logs the given exception to System.out.
protected voidlogWarn(Exception ex)
Logs the given exception to System.err.
Objectput(Object name, Object value)
Sets the bean property with the given name to the given value.
voidputAllWriteable(BeanMap map)
Puts all of the writable properties from the given BeanMap into this BeanMap.
protected voidreinitialise()
Reinitializes this bean.
voidsetBean(Object newBean)
Sets the bean to be operated on by this map.
intsize()
Returns the number of properties defined by the bean.
StringtoString()
IteratorvalueIterator()
Convenience method for getting an iterator over the values.
Collectionvalues()
Returns the values for the BeanMap.

Field Detail

defaultTransformers

public static HashMap defaultTransformers
Maps primitive Class types to transformers. The transformer transform strings into the appropriate primitive wrapper.

NULL_ARGUMENTS

public static final Object[] NULL_ARGUMENTS
An empty array. Used to invoke accessors via reflection.

Constructor Detail

BeanMap

public BeanMap()
Constructs a new empty BeanMap.

BeanMap

public BeanMap(Object bean)
Constructs a new BeanMap that operates on the specified bean. If the given bean is null, then this map will be empty.

Parameters: bean the bean for this map to operate on

Method Detail

clear

public void clear()
This method reinitializes the bean map to have default values for the bean's properties. This is accomplished by constructing a new instance of the bean which the map uses as its underlying data source. This behavior for clear() differs from the Map contract in that the mappings are not actually removed from the map (the mappings for a BeanMap are fixed).

clone

public Object clone()
Clone this bean map using the following process:

containsKey

public boolean containsKey(Object name)
Returns true if the bean defines a property with the given name.

The given name must be a String; if not, this method returns false. This method will also return false if the bean does not define a property with that name.

Write-only properties will not be matched as the test operates against property read methods.

Parameters: name the name of the property to check

Returns: false if the given name is null or is not a String; false if the bean does not define a property with that name; or true if the bean does define a property with that name

containsValue

public boolean containsValue(Object value)
Returns true if the bean defines a property whose current value is the given object.

Parameters: value the value to check

Returns: false true if the bean has at least one property whose current value is that object, false otherwise

convertType

protected Object convertType(Class newType, Object value)
Converts the given value to the given type. First, reflection is is used to find a public constructor declared by the given class that takes one argument, which must be the precise type of the given value. If such a constructor is found, a new object is created by passing the given value to that constructor, and the newly constructed object is returned.

If no such constructor exists, and the given type is a primitive type, then the given value is converted to a string using its Object#toString() toString() method, and that string is parsed into the correct primitive type using, for instance, Integer#valueOf(String) to convert the string into an int.

If no special constructor exists and the given type is not a primitive type, this method returns the original value.

Parameters: newType the type to convert the value to value the value to convert

Returns: the converted value

Throws: NumberFormatException if newType is a primitive type, and the string representation of the given value cannot be converted to that type InstantiationException if the constructor found with reflection raises it InvocationTargetException if the constructor found with reflection raises it IllegalAccessException never IllegalArgumentException never

createWriteMethodArguments

protected Object[] createWriteMethodArguments(Method method, Object value)
Creates an array of parameters to pass to the given mutator method. If the given object is not the right type to pass to the method directly, it will be converted using convertType.

Parameters: method the mutator method value the value to pass to the mutator method

Returns: an array containing one object that is either the given value or a transformed value

Throws: IllegalAccessException if convertType raises it IllegalArgumentException if any other exception is raised by convertType

entryIterator

public Iterator entryIterator()
Convenience method for getting an iterator over the entries.

Returns: an iterator over the entries

entrySet

public Set entrySet()
Gets a Set of MapEntry objects that are the mappings for this BeanMap.

Each MapEntry can be set but not removed.

Returns: the unmodifiable set of mappings

firePropertyChange

protected void firePropertyChange(Object key, Object oldValue, Object newValue)
Called during a successful put operation. Default implementation does nothing. Override to be notified of property changes in the bean caused by this map.

Parameters: key the name of the property that changed oldValue the old value for that property newValue the new value for that property

get

public Object get(Object name)
Returns the value of the bean's property with the given name.

The given name must be a String and must not be null; otherwise, this method returns null. If the bean defines a property with the given name, the value of that property is returned. Otherwise, null is returned.

Write-only properties will not be matched as the test operates against property read methods.

Parameters: name the name of the property whose value to return

Returns: the value of the property with that name

getBean

public Object getBean()
Returns the bean currently being operated on. The return value may be null if this map is empty.

Returns: the bean being operated on by this map

getReadMethod

public Method getReadMethod(String name)
Returns the accessor for the property with the given name.

Parameters: name the name of the property

Returns: the accessor method for the property, or null

getReadMethod

protected Method getReadMethod(Object name)
Returns the accessor for the property with the given name.

Parameters: name the name of the property

Returns: null if the name is null; null if the name is not a String; null if no such property exists; or the accessor method for that property

getType

public Class getType(String name)
Returns the type of the property with the given name.

Parameters: name the name of the property

Returns: the type of the property, or null if no such property exists

getTypeTransformer

protected Transformer getTypeTransformer(Class aType)
Returns a transformer for the given primitive type.

Parameters: aType the primitive type whose transformer to return

Returns: a transformer that will convert strings into that type, or null if the given type is not a primitive type

getWriteMethod

public Method getWriteMethod(String name)
Returns the mutator for the property with the given name.

Parameters: name the name of the property

Returns: the mutator method for the property, or null

getWriteMethod

protected Method getWriteMethod(Object name)
Returns the mutator for the property with the given name.

Parameters: name the name of the

Returns: null if the name is null; null if the name is not a String; null if no such property exists; null if the property is read-only; or the mutator method for that property

keyIterator

public Iterator keyIterator()
Convenience method for getting an iterator over the keys.

Write-only properties will not be returned in the iterator.

Returns: an iterator over the keys

keySet

public Set keySet()
Get the keys for this BeanMap.

Write-only properties are not included in the returned set of property names, although it is possible to set their value and to get their type.

Returns: BeanMap keys. The Set returned by this method is not modifiable.

logInfo

protected void logInfo(Exception ex)
Logs the given exception to System.out. Used to display warnings while accessing/mutating the bean.

Parameters: ex the exception to log

logWarn

protected void logWarn(Exception ex)
Logs the given exception to System.err. Used to display errors while accessing/mutating the bean.

Parameters: ex the exception to log

put

public Object put(Object name, Object value)
Sets the bean property with the given name to the given value.

Parameters: name the name of the property to set value the value to set that property to

Returns: the previous value of that property

Throws: IllegalArgumentException if the given name is null; if the given name is not a String; if the bean doesn't define a property with that name; or if the bean property with that name is read-only

putAllWriteable

public void putAllWriteable(BeanMap map)
Puts all of the writable properties from the given BeanMap into this BeanMap. Read-only and Write-only properties will be ignored.

Parameters: map the BeanMap whose properties to put

reinitialise

protected void reinitialise()
Reinitializes this bean. Called during setBean. Does introspection to find properties.

setBean

public void setBean(Object newBean)
Sets the bean to be operated on by this map. The given value may be null, in which case this map will be empty.

Parameters: newBean the new bean to operate on

size

public int size()
Returns the number of properties defined by the bean.

Returns: the number of properties defined by the bean

toString

public String toString()

valueIterator

public Iterator valueIterator()
Convenience method for getting an iterator over the values.

Returns: an iterator over the values

values

public Collection values()
Returns the values for the BeanMap.

Returns: values for the BeanMap. The returned collection is not modifiable.

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