public class XMLBeanDeclaration extends Object implements BeanDeclaration
An implementation of the BeanDeclaration
interface that is suitable for XML configuration files.
This class defines the standard layout of a bean declaration in an XML configuration file. Such a declaration must look like the following example fragment:
... <personBean config-class="my.model.PersonBean" lastName="Doe" firstName="John"> <config-constrarg config-value="ID03493" config-type="java.lang.String"/> <address config-class="my.model.AddressBean" street="21st street 11" zip="1234" city="TestCity"/> </personBean>
The bean declaration can be contained in an arbitrary element. Here it is the personBean
element. In the
attributes of this element there can occur some reserved attributes, which have the following meaning:
config-class
defaultClass
passed to the BeanHelper
class.config-factory
BeanFactory
that should be used for creating the bean. If it
is defined, a factory with this name must have been registered at the BeanHelper
class. If this attribute is
missing, the default bean factory will be used.config-factoryParam
All further attributes starting with the config-
prefix are considered as meta data and will be ignored. All
other attributes are treated as properties of the bean to be created, i.e. corresponding setter methods of the bean
will be invoked with the values specified here.
If the bean to be created has also some complex properties (which are itself beans), their values cannot be initialized from attributes. For this purpose nested elements can be used. The example listing shows how an address bean can be initialized. This is done in a nested element whose name must match the name of a property of the enclosing bean declaration. The format of this nested element is exactly the same as for the bean declaration itself, i.e. it can have attributes defining meta data or bean properties and even further nested elements for complex bean properties.
If the bean should be created using a specific constructor, the constructor arguments have to be specified. This is
done by an arbitrary number of nested <config-constrarg>
elements. Each element can either have the
config-value
attribute - then it defines a simple value - or must be again a bean declaration (conforming to
the format defined here) defining the complex value of this constructor argument.
A XMLBeanDeclaration
object is usually created from a HierarchicalConfiguration
. From this it will
derive a SubnodeConfiguration
, which is used to access the needed properties. This subnode configuration can
be obtained using the getConfiguration()
method. All of its properties can be accessed in the usual way. To
ensure that the property keys used by this class are understood by the configuration, the default expression engine
will be set.
Modifier and Type | Field and Description |
---|---|
static String |
ATTR_BEAN_CLASS
Constant for the bean class attribute.
|
static String |
ATTR_BEAN_FACTORY
Constant for the bean factory attribute.
|
static String |
ATTR_FACTORY_PARAM
Constant for the bean factory parameter attribute.
|
static String |
ATTR_PREFIX
Constant for the prefix for reserved attributes.
|
static String |
RESERVED_PREFIX
Constant for the prefix of reserved attributes.
|
Constructor and Description |
---|
XMLBeanDeclaration(HierarchicalConfiguration<T> config)
Constructs a new instance of
XMLBeanDeclaration and initializes it from the given configuration. |
XMLBeanDeclaration(HierarchicalConfiguration<T> config,
String key)
Constructs a new instance of
XMLBeanDeclaration and initializes it from the given configuration. |
XMLBeanDeclaration(HierarchicalConfiguration<T> config,
String key,
boolean optional)
Constructs a new instance of
XMLBeanDeclaration and initializes it from the given configuration supporting
optional declarations. |
XMLBeanDeclaration(HierarchicalConfiguration<T> config,
String key,
boolean optional,
String defBeanClsName)
Constructs a new instance of
XMLBeanDeclaration and initializes it from the given configuration supporting
optional declarations and a default bean class name. |
Modifier and Type | Method and Description |
---|---|
protected Set<String> |
getAttributeNames()
Gets a set with the names of the attributes of the configuration node holding the data of this bean declaration.
|
String |
getBeanClassName()
Gets the name of the class of the bean to be created.
|
String |
getBeanFactoryName()
Gets the name of the bean factory.
|
Object |
getBeanFactoryParameter()
Gets a parameter for the bean factory.
|
Map<String,Object> |
getBeanProperties()
Gets a map with the bean's (simple) properties.
|
HierarchicalConfiguration<?> |
getConfiguration()
Gets the configuration object this bean declaration is based on.
|
Collection<ConstructorArg> |
getConstructorArgs()
Gets a collection with constructor arguments.
|
String |
getDefaultBeanClassName()
Gets the name of the default bean class.
|
Map<String,Object> |
getNestedBeanDeclarations()
Gets a map with bean declarations for the complex properties of the bean to be created.
|
protected Object |
interpolate(Object value)
Performs interpolation for the specified value.
|
protected boolean |
isReservedAttributeName(String name)
Tests if the specified attribute name is reserved and thus does not point to a property of the bean to be created.
|
protected boolean |
isReservedChildName(String name)
Tests if the specified child node name is reserved and thus should be ignored.
|
protected boolean |
isReservedName(String name)
Tests if the specified name of a node or attribute is reserved and thus should be ignored.
|
public static final String RESERVED_PREFIX
public static final String ATTR_PREFIX
public static final String ATTR_BEAN_CLASS
public static final String ATTR_BEAN_FACTORY
public static final String ATTR_FACTORY_PARAM
public XMLBeanDeclaration(HierarchicalConfiguration<T> config, String key)
XMLBeanDeclaration
and initializes it from the given configuration. The passed in
key points to the bean declaration.T
- the node type of the configurationconfig
- the configuration (must not be null)key
- the key to the bean declaration (this key must point to exactly one bean declaration or a
IllegalArgumentException
exception will be thrown)IllegalArgumentException
- if required information is missing to construct the bean declarationpublic XMLBeanDeclaration(HierarchicalConfiguration<T> config, String key, boolean optional)
XMLBeanDeclaration
and initializes it from the given configuration supporting
optional declarations.T
- the node type of the configurationconfig
- the configuration (must not be null)key
- the key to the bean declarationoptional
- a flag whether this declaration is optional; if set to true, no exception will be thrown if
the passed in key is undefinedIllegalArgumentException
- if required information is missing to construct the bean declarationpublic XMLBeanDeclaration(HierarchicalConfiguration<T> config, String key, boolean optional, String defBeanClsName)
XMLBeanDeclaration
and initializes it from the given configuration supporting
optional declarations and a default bean class name. The passed in key points to the bean declaration. If the key
does not exist and the boolean argument is true, the declaration is initialized with an empty configuration.
It is possible to create objects from such an empty declaration if a default class is provided. If the key on the
other hand has multiple values or is undefined and the boolean argument is false, a
IllegalArgumentException
exception will be thrown. It is possible to set a default bean class name; this name
is used if the configuration does not contain a bean class.T
- the node type of the configurationconfig
- the configuration (must not be null)key
- the key to the bean declarationoptional
- a flag whether this declaration is optional; if set to true, no exception will be thrown if
the passed in key is undefineddefBeanClsName
- a default bean class nameIllegalArgumentException
- if required information is missing to construct the bean declarationpublic XMLBeanDeclaration(HierarchicalConfiguration<T> config)
XMLBeanDeclaration
and initializes it from the given configuration. The
configuration's root node must contain the bean declaration.T
- the node type of the configurationconfig
- the configuration with the bean declarationpublic HierarchicalConfiguration<?> getConfiguration()
public String getDefaultBeanClassName()
public String getBeanFactoryName()
config-factory
attribute.getBeanFactoryName
in interface BeanDeclaration
public Object getBeanFactoryParameter()
config-factoryParam
attribute.getBeanFactoryParameter
in interface BeanDeclaration
public String getBeanClassName()
config-class
attribute.getBeanClassName
in interface BeanDeclaration
public Map<String,Object> getBeanProperties()
getBeanProperties
in interface BeanDeclaration
public Map<String,Object> getNestedBeanDeclarations()
getNestedBeanDeclarations
in interface BeanDeclaration
public Collection<ConstructorArg> getConstructorArgs()
config-constrarg
. If such a node
has a config-class
attribute, it is considered a nested bean declaration; otherwise it is interpreted as a
simple value. If no nested constructor argument declarations are found, result is an empty collection.getConstructorArgs
in interface BeanDeclaration
protected Object interpolate(Object value)
value
- the value that is to be interpolatedprotected boolean isReservedChildName(String name)
isReservedName(String)
.name
- the name of the child node to be checkedprotected boolean isReservedAttributeName(String name)
isReservedName(String)
.name
- the name of the attribute to be checkedprotected boolean isReservedName(String name)
name
- the name to be checkedprotected Set<String> getAttributeNames()
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