/*****************************************************************************
* Copyright (c) PicoContainer Organization. All rights reserved. *
* ------------------------------------------------------------------------- *
* The software in this package is published under the terms of the BSD *
* style license a copy of which has been included with this distribution in *
* the LICENSE.txt file. *
* *
* Idea by Rachel Davies, Original code by Jon Tirsen *
*****************************************************************************/
package org.picocontainer.defaults;
import org.picocontainer.ComponentAdapter;
import org.picocontainer.Parameter;
import org.picocontainer.PicoContainer;
import org.picocontainer.PicoException;
import org.picocontainer.PicoIntrospectionException;
import org.picocontainer.PicoVisitor;
import java.io.Serializable;
import java.lang.reflect.Field;
/**
* A ConstantParameter should be used to pass in "constant" arguments to constructors. This
* includes {@link String}s,{@link Integer}s or any other object that is not registered in
* the container.
*
* @author Jon Tirsén
* @author Aslak Hellesøy
* @author Jörg Schaible
* @author Thomas Heller
* @version $Revision: 1801 $
*/
public class ConstantParameter
implements Parameter, Serializable {
private final Object value;
public ConstantParameter(Object value) {
this.value = value;
}
public Object resolveInstance(PicoContainer container, ComponentAdapter adapter, Class expectedType) {
return value;
}
public boolean isResolvable(PicoContainer container, ComponentAdapter adapter, Class expectedType) {
try {
verify(container, adapter, expectedType);
return true;
} catch(final PicoIntrospectionException e) {
return false;
}
}
/**
* {@inheritDoc}
*
* @see org.picocontainer.Parameter#verify(org.picocontainer.PicoContainer,
* org.picocontainer.ComponentAdapter, java.lang.Class)
*/
public void verify(PicoContainer container, ComponentAdapter adapter, Class expectedType) throws PicoException {
if (!checkPrimitive(expectedType) && !expectedType.isInstance(value)) {
throw new PicoIntrospectionException(expectedType.getClass().getName()
+ " is not assignable from "
+ value.getClass().getName());
}
}
/**
* Visit the current {@link Parameter}.
*
* @see org.picocontainer.Parameter#accept(org.picocontainer.PicoVisitor)
*/
public void accept(final PicoVisitor visitor) {
visitor.visitParameter(this);
}
private boolean checkPrimitive(Class expectedType) {
try {
if (expectedType.isPrimitive()) {
final Field field = value.getClass().getField("TYPE");
final Class type = (Class) field.get(value);
return expectedType.isAssignableFrom(type);
}
} catch (NoSuchFieldException e) {
} catch (IllegalAccessException e) {
}
return false;
}
}