ConstructorArg (Apache Commons Configuration 2.7 API)

java.lang.Object
- org.apache.commons.configuration2.beanutils.ConstructorArg

```
public final class ConstructorArg
extends Object
```
A class representing an argument for a constructor invocation to be used by a BeanDeclaration.

A BeanDeclaration can provide a list of instances of this class to define the constructor to be invoked on the bean class. Each constructor argument can either be a simple value or a nested BeanDeclaration. In the latter case, the bean is resolved recursively.

The constructor to be invoked on the bean class has to be determined based on the types of the constructor arguments. To avoid ambiguity, the type name can be explicitly provided.

Since:

2.0

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static ConstructorArg`	`forBeanDeclaration(BeanDeclaration decl)` Creates a new instance of `ConstructorArg` for the specified `BeanDeclaration`.
`static ConstructorArg`	`forBeanDeclaration(BeanDeclaration beanDeclaration, String typeName)` Creates a new instance of `ConstructorArg` for the specified `BeanDeclaration` and sets the type name explicitly.
`static ConstructorArg`	`forValue(Object value)` Creates a new instance of `ConstructorArg` for the specified simple value.
`static ConstructorArg`	`forValue(Object value, String typeName)` Creates a new instance of `ConstructorArg` for the specified simple value and sets the type name explicitly.
`BeanDeclaration`	`getBeanDeclaration()` Returns the `BeanDeclaration` referenced by this constructor argument.
`String`	`getTypeName()` Returns the optional data type name of this constructor argument.
`Object`	`getValue()` Returns the value of this constructor argument.
`boolean`	`isNestedBeanDeclaration()` Returns a flag whether this constructor argument represents a `BeanDeclaration`.
`boolean`	`matches(Class<?> argCls)` Checks whether this constructor argument is compatible with the given class.
`String`	`toString()` Returns a string representation of this object.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Method Detail
  - forBeanDeclaration
```
public static ConstructorArg forBeanDeclaration(BeanDeclaration decl)
```
    Creates a new instance of ConstructorArg for the specified BeanDeclaration. The actual value of this argument is the resolved BeanDeclaration.
    
    Parameters:
    
    decl - the BeanDeclaration
    
    Returns:
    
    the newly created instance of this class
    
    Throws:
    
    NullPointerException - if the BeanDeclaration is null
  - forBeanDeclaration
```
public static ConstructorArg forBeanDeclaration(BeanDeclaration beanDeclaration,
                                                String typeName)
```
    Creates a new instance of ConstructorArg for the specified BeanDeclaration and sets the type name explicitly. The type name is used to match this argument against the parameter type of a constructor or the bean class.
    
    Parameters:
    
    beanDeclaration - the BeanDeclaration
    
    typeName - the name of the data type of this argument
    
    Returns:
    
    the newly created instance of this class
    
    Throws:
    
    NullPointerException - if the BeanDeclaration is null
  - forValue
```
public static ConstructorArg forValue(Object value)
```
    Creates a new instance of ConstructorArg for the specified simple value. The value is passed to the constructor invocation.
    
    Parameters:
    
    value - the value of this constructor argument (may be null)
    
    Returns:
    
    the newly created instance of this class
  - forValue
```
public static ConstructorArg forValue(Object value,
                                      String typeName)
```
    Creates a new instance of ConstructorArg for the specified simple value and sets the type name explicitly. The type name is used to match this argument against the parameter type of a constructor or the bean class.
    
    Parameters:
    
    value - the value of this constructor argument (may be null)
    
    typeName - the name of the data type of this argument
    
    Returns:
    
    the newly created instance of this class
  - getBeanDeclaration
```
public BeanDeclaration getBeanDeclaration()
```
    Returns the BeanDeclaration referenced by this constructor argument. A return value of null means that this constructor argument does not have a bean declaration as value; in this case, the value can be queried using the getValue() method.
    
    Returns:
    
    the referenced BeanDeclaration or null
  - isNestedBeanDeclaration
```
public boolean isNestedBeanDeclaration()
```
    Returns a flag whether this constructor argument represents a BeanDeclaration. If this method returns true, the actual value of this argument can be obtained by resolving the bean declaration returned by getBeanDeclaration(). Otherwise, this argument has a simple value which can be queried using getValue().
    
    Returns:
    
    a flag whether this constructor argument references a bean declaration
  - getValue
```
public Object getValue()
```
    Returns the value of this constructor argument. This method can be queried if isNestedBeanDeclaration() returns false. Note that a return value of null is legal (to pass null to a constructor argument).
    
    Returns:
    
    the simple value of this constructor argument
  - getTypeName
```
public String getTypeName()
```
    Returns the optional data type name of this constructor argument. The type name can be specified as a hint to select a specific constructor if there are ambiguities. Note that it does not necessarily has to match the data type of this argument's value because a type conversion may be performed before invoking the constructor.
    
    Returns:
    
    the data type name of this argument if defined or null otherwise
  - matches
```
public boolean matches(Class<?> argCls)
```
    Checks whether this constructor argument is compatible with the given class. This method is called to determine a matching constructor. It compares the argument's data type with the class name if it is defined. If no type name has been set, result is true as it is assumed that a type conversion can be performed when calling the constructor. This means that per default only the number of constructor arguments is checked to find a matching constructor. Only if there are multiple constructors with the same number of arguments, explicit type names have to be provided to select a specific constructor.
    
    Parameters:
    
    argCls - the class of the constructor argument to compare with
    
    Returns:
    
    true if this constructor argument is compatible with this class, false otherwise
  - toString
```
public String toString()
```
    Returns a string representation of this object. This string contains the value of this constructor argument and the explicit type if provided.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string for this object

Class ConstructorArg

Method Summary

Methods inherited from class java.lang.Object

Method Detail

forBeanDeclaration

forBeanDeclaration

forValue

forValue

getBeanDeclaration

isNestedBeanDeclaration

getValue

getTypeName

matches

toString