net.sf.jguiraffe.di.impl

Class ConstructorInvocation

java.lang.Object

net.sf.jguiraffe.di.impl.Invocation

net.sf.jguiraffe.di.impl.ConstructorInvocation

All Implemented Interfaces:

Invokable

public class ConstructorInvocation
extends Invocation
implements Invokable

A class that represents a constructor invocation.

Instances of this class can be used for creating objects by invoking constructors on their classes. For this purpose the parameters to be passed to the constructor must be specified, which is done in form of an array of Dependency objects. These dependencies can either refer to other beans (they will then be resolved by the dependency injection framework), or can contain constant values that will be directly passed to the constructor. If the constructor's signature is known, the types of its arguments can be defined. If this is not the case, the parameter types will be derived from the current parameter values. The InvocationHelper class is used to find the correct constructor to be invoked.

Objects of this class cannot be changed after they have been created. So they can be shared between multiple clients.

Version:

$Id: ConstructorInvocation.java 205 2012-01-29 18:29:57Z oheger $

Author:

Oliver Heger

Constructor Summary

Constructors

Constructor and Description
ConstructorInvocation(ClassDescription targetClass, ClassDescription[] paramTypes, Dependency... paramValues) Creates a new instance of ConstructorInvocation and initializes it.

Method Summary

Modifier and Type	Method and Description
protected void	invocationInfoToString(StringBuilder buf) Adds additional information about this invocation to the string buffer.
Object	invoke(DependencyProvider depProvider) Invokes the corresponding constructor on the specified target class and returns the newly created instance.
Object	invoke(DependencyProvider depProvider, Object target) Performs the invocation.

Methods inherited from class net.sf.jguiraffe.di.impl.Invocation

checkDependencyProvider, getParameterClasses, getParameterDependencies, getParameterTypes, getResolvedParameters, getTargetClass, isTypeInfoComplete, parametersToString, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.jguiraffe.di.impl.Invokable

getParameterDependencies

Constructor Detail

ConstructorInvocation

public ConstructorInvocation(ClassDescription targetClass,
                             ClassDescription[] paramTypes,
                             Dependency... paramValues)

Creates a new instance of ConstructorInvocation and initializes it. Refer to the base class for a detailed explanation of the arguments.

Parameters:

targetClass - the class, on which the method is to be invoked (must not be null)

paramTypes - an array with the parameter types

paramValues - the current parameter values (defined as Dependency objects); this array must not contain null elements

Throws:

IllegalArgumentException - if the length of the parameter types array does not match the length of the parameter values array, or if the values array contains null elements, of if the target class is null

See Also:

Invocation#Invocation(Class, Class[], Dependency...)

Method Detail

invoke

public Object invoke(DependencyProvider depProvider)

Invokes the corresponding constructor on the specified target class and returns the newly created instance. The required dependencies are resolved using the given DependencyProvider.

Parameters:

depProvider - the dependency provider (must not be null)

Returns:

the newly created instance of the target class

Throws:

InjectionException - if an error occurs

IllegalArgumentException - if the dependency provider is null

invoke

public Object invoke(DependencyProvider depProvider,
                     Object target)

Performs the invocation. This method is required by the Invokable interface. It delegates to the method with the same name, ignoring the target parameter (which is not needed for a constructor invocation).

Specified by:

invoke in interface Invokable

Parameters:

depProvider - the dependency provider (must not be null)

target - the target of the invocation

Returns:

the result of the invocation

Throws:

InjectionException - if an error occurs

IllegalArgumentException - if the dependency provider is null

invocationInfoToString

protected void invocationInfoToString(StringBuilder buf)

Adds additional information about this invocation to the string buffer. This implementation adds a name for the constructor.

Overrides:

invocationInfoToString in class Invocation

Parameters:

buf - the target buffer