/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.beans.metadata.plugins;
import java.io.Serializable;
import java.util.Stack;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlTransient;
import org.jboss.beans.info.spi.BeanInfo;
import org.jboss.beans.info.spi.PropertyInfo;
import org.jboss.beans.metadata.spi.BeanMetaData;
import org.jboss.beans.metadata.spi.MetaDataVisitor;
import org.jboss.beans.metadata.spi.MetaDataVisitorNode;
import org.jboss.beans.metadata.spi.PropertyMetaData;
import org.jboss.dependency.spi.Controller;
import org.jboss.dependency.spi.ControllerContext;
import org.jboss.dependency.spi.ControllerState;
import org.jboss.dependency.spi.dispatch.AttributeDispatchContext;
import org.jboss.kernel.plugins.config.Configurator;
import org.jboss.kernel.spi.config.KernelConfigurator;
import org.jboss.kernel.spi.dependency.KernelControllerContext;
import org.jboss.reflect.spi.ClassInfo;
import org.jboss.reflect.spi.TypeInfo;
import org.jboss.util.JBossStringBuilder;
import org.jboss.joinpoint.spi.Joinpoint;
/**
* A typed value.
*
* @author <a href="adrian@jboss.com">Adrian Brock</a>
* @author <a href="ales.justin@jboss.com">Ales Justin</a>
* @version $Revision: 68654 $
*/
public abstract class AbstractTypeMetaData extends AbstractValueMetaData
implements Serializable
{
private static final long serialVersionUID = 3L;
/**
* The type
*/
protected String type;
/**
* The context
*/
protected transient ControllerContext context;
/**
* The configurator
*/
protected transient KernelConfigurator configurator;
/**
* The property name
*/
protected String propertyName;
/**
* The bean name
*/
protected String beanName;
/**
* Create a new typed value
*/
public AbstractTypeMetaData()
{
}
/**
* Create a new typed value
*
* @param value the value
*/
public AbstractTypeMetaData(String value)
{
super(value);
}
/**
* Set the type
*
* @param type the type
*/
@XmlAttribute(name="class")
public void setType(String type)
{
this.type = type;
}
public String getType()
{
return type;
}
public void initialVisit(MetaDataVisitor visitor)
{
context = visitor.getControllerContext();
configurator = visitor.getControllerContext().getKernel().getConfigurator();
preparePreinstantiatedLookup(visitor);
visitor.initialVisit(this);
}
/**
* Check if we can extract the information about
* existing instance - only on property metadata.
*
* @param visitor underlying visitor
*/
protected void preparePreinstantiatedLookup(MetaDataVisitor visitor)
{
Stack<MetaDataVisitorNode> visitorNodes = visitor.visitorNodeStack();
// pop it so that we can get to grand parent for more info
MetaDataVisitorNode parent = visitorNodes.pop();
try
{
if (parent instanceof PropertyMetaData)
{
PropertyMetaData pmd = (PropertyMetaData)parent;
if (pmd.isPreInstantiate())
{
propertyName = pmd.getName();
Object gp = visitorNodes.peek();
if (gp instanceof BeanMetaData)
{
BeanMetaData bmd = (BeanMetaData)gp;
beanName = bmd.getName();
}
}
}
}
finally
{
visitorNodes.push(parent);
}
}
/**
* Check for already existing instances.
*
* @param <T> expected type
* @param cl the classloader
* @param expected the expected class
* @return existing instance or null otherwise
*/
protected <T> T preinstantiatedLookup(ClassLoader cl, Class<T> expected)
{
if (propertyName != null && beanName != null)
{
Object result = null;
try
{
Controller controller = context.getController();
ControllerContext context = controller.getContext(beanName, ControllerState.INSTANTIATED);
if (context != null && context instanceof AttributeDispatchContext)
{
Object target = context.getTarget();
if (target != null)
{
BeanInfo beanInfo = configurator.getBeanInfo(target.getClass());
PropertyInfo pi = Configurator.resolveProperty(log.isTraceEnabled(), beanInfo, cl, propertyName, null);
if (pi.getGetter() != null)
{
result = ((AttributeDispatchContext)context).get(propertyName);
}
}
}
}
catch (Throwable t)
{
log.warn("Exception in preinstantiated lookup for: " + beanName + "." + propertyName + ", " + t);
}
return checkResult(result, expected);
}
return null;
}
/**
* Check result for class compatibility.
*
* @param <T> the expected type
* @param result the result
* @param expected expected class
* @return casted result
* @throws ClassCastException if result cannot be casted into expected parameter
*/
protected <T> T checkResult(Object result, Class<T> expected)
{
if (result != null && expected.isAssignableFrom(result.getClass()) == false)
throw new ClassCastException(result.getClass() + " is not a " + expected.getName());
return expected.cast(result);
}
/**
* Create new instance from type field.
* Fall back to info parameter if no type field is set.
*
* @param <T> expected type
* @param info the type of reference we are about to set
* @param cl the classloader to use
* @param expected the expected class
* @param explicit is type explicit
* @return class instance or null if type is too broad
* @throws Throwable on any error
*/
protected <T> T createInstance(TypeInfo info, ClassLoader cl, Class<T> expected, boolean explicit) throws Throwable
{
if (info == null || Object.class.getName().equals(info.getName()))
return null;
if (info instanceof ClassInfo == false)
{
if (explicit)
throw new IllegalArgumentException(info.getName() + " is not a class");
else
return null;
}
if (((ClassInfo) info).isInterface())
{
if (explicit)
throw new IllegalArgumentException(info.getName() + " is an interface");
else
return null;
}
BeanInfo beanInfo = configurator.getBeanInfo(info);
Joinpoint constructor = configurator.getConstructorJoinPoint(beanInfo);
Object result = constructor.dispatch();
if (expected.isAssignableFrom(result.getClass()) == false)
throw new ClassCastException(result.getClass() + " is not a " + expected.getName());
return expected.cast(result);
}
/**
* Create the class instance
*
* @param <T> expected type
* @param info the request type
* @param cl the classloader
* @param expected the expected class
* @return the class instance
* @throws Throwable for any error
*/
protected <T> T getTypeInstance(TypeInfo info, ClassLoader cl, Class<T> expected) throws Throwable
{
T result = null;
TypeInfo typeInfo = getClassInfo(cl);
// we have explicitly set type
if (typeInfo != null)
result = createInstance(typeInfo, cl, expected, true);
if (result == null)
{
result = preinstantiatedLookup(cl, expected);
// try info param
if (result == null)
{
result = createInstance(info, cl, expected, false);
// get default
if (result == null)
result = expected.cast(getDefaultInstance());
}
}
return result;
}
/**
* Get the default instance.
*
* @return the default instance
*/
protected abstract Object getDefaultInstance();
/**
* Set the configurator
*
* @param configurator the configurator
*/
@XmlTransient
public void setConfigurator(KernelConfigurator configurator)
{
this.configurator = configurator;
}
public void toString(JBossStringBuilder buffer)
{
super.toString(buffer);
if (type != null)
buffer.append(" type=").append(type);
}
/**
* Get the class info for this type
*
* @param cl classloader
* @return the class info
* @throws Throwable for any error
*/
protected ClassInfo getClassInfo(ClassLoader cl) throws Throwable
{
return getClassInfo(type, cl);
}
protected ClassInfo getClassInfo(String classType, ClassLoader cl) throws Throwable
{
if (classType == null)
return null;
return configurator.getClassInfo(classType, cl);
}
protected ClassInfo getClass(MetaDataVisitor visitor, String classType) throws Throwable
{
KernelControllerContext context = visitor.getControllerContext();
ClassLoader cl = Configurator.getClassLoader(context.getBeanMetaData());
return getClassInfo(classType, cl);
}
}