org.directwebremoting.impl.DefaultContainer Maven / Gradle / Ivy
/*
* Copyright 2005 Joe Walker
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.directwebremoting.impl;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;
import javax.servlet.Servlet;
import org.directwebremoting.Container;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Logger;
/**
* DefaultContainer is like a mini-IoC container for DWR.
* At least it is an IoC container by interface (check: no params that have
* anything to do with DWR), but it is hard coded specifically for DWR. If we
* want to make more of it we can later, but this is certainly not going to
* become a full blown IoC container.
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class DefaultContainer extends AbstractContainer implements Container
{
/**
* Set the class that should be used to implement the given interface
* @param askFor The interface to implement
* @param valueParam The new implementation
* @throws IllegalAccessException If the specified beans could not be accessed
* @throws InstantiationException If the specified beans could not be created
*/
public void addParameter(Object askFor, Object valueParam) throws InstantiationException, IllegalAccessException
{
Object value = valueParam;
// Maybe the value is a classname that needs instansiating
if (value instanceof String)
{
try
{
Class impl = LocalUtil.classForName((String) value);
value = impl.newInstance();
}
catch (ClassNotFoundException ex)
{
// it's not a classname, leave it
}
}
// If we have an instansiated value object and askFor is an interface
// then we can check that one implements the other
if (!(value instanceof String) && askFor instanceof String)
{
try
{
Class iface = LocalUtil.classForName((String) askFor);
if (!iface.isAssignableFrom(value.getClass()))
{
log.error("Can't cast: " + value + " to " + askFor);
}
}
catch (ClassNotFoundException ex)
{
// it's not a classname, leave it
}
}
if (log.isDebugEnabled())
{
if (value instanceof String)
{
log.debug("Adding IoC setting: " + askFor + "=" + value);
}
else
{
log.debug("Adding IoC implementation: " + askFor + "=" + value.getClass().getName());
}
}
beans.put(askFor, value);
}
/**
* Called to indicate that we finished adding parameters.
* The thread safety of a large part of DWR depends on this function only
* being called from {@link Servlet#init(javax.servlet.ServletConfig)},
* where all the setup is done, and where we depend on the undocumented
* feature of all servlet containers that they complete the init process
* of a Servlet before they begin servicing requests.
* @see DefaultContainer#addParameter(Object, Object)
* @noinspection UnnecessaryLabelOnContinueStatement
*/
public void setupFinished()
{
// We try to autowire each bean in turn
for (Iterator it = beans.entrySet().iterator(); it.hasNext();)
{
Map.Entry entry = (Map.Entry) it.next();
// Class type = (Class) entry.getKey();
Object ovalue = entry.getValue();
if (!(ovalue instanceof String))
{
log.debug("Trying to autowire: " + ovalue.getClass().getName());
Method[] methods = ovalue.getClass().getMethods();
methods:
for (int i = 0; i < methods.length; i++)
{
Method setter = methods[i];
if (setter.getName().startsWith("set") &&
setter.getName().length() > 3 &&
setter.getParameterTypes().length == 1)
{
String name = Character.toLowerCase(setter.getName().charAt(3)) + setter.getName().substring(4);
Class propertyType = setter.getParameterTypes()[0];
// First we try auto-wire by name
Object setting = beans.get(name);
if (setting != null)
{
if (propertyType.isAssignableFrom(setting.getClass()))
{
log.debug("- autowire-by-name: " + name + "=" + setting);
invoke(setter, ovalue, setting);
continue methods;
}
else if (setting.getClass() == String.class)
{
try
{
Object value = LocalUtil.simpleConvert((String) setting, propertyType);
log.debug("- autowire-by-name: " + name + "=" + value);
invoke(setter, ovalue, value);
}
catch (IllegalArgumentException ex)
{
// Ignore - this was a specuative convert anyway
}
continue methods;
}
}
// Next we try autowire-by-type
Object value = beans.get(propertyType.getName());
if (value != null)
{
log.debug("- autowire-by-type: " + name + "=" + value.getClass().getName());
invoke(setter, ovalue, value);
continue methods;
}
log.debug("- skipped autowire: " + name);
}
}
}
}
callInitializingBeans();
}
/**
* A helper to do the reflection.
* This helper throws away all exceptions, prefering to log.
* @param setter The method to invoke
* @param bean The object to invoke the method on
* @param value The value to assign to the property using the setter method
*/
private static void invoke(Method setter, Object bean, Object value)
{
try
{
setter.invoke(bean, new Object[] { value });
}
catch (IllegalArgumentException ex)
{
log.error("- Internal error: " + ex.getMessage());
}
catch (IllegalAccessException ex)
{
log.error("- Permission error: " + ex.getMessage());
}
catch (InvocationTargetException ex)
{
log.error("- Exception during auto-wire: ", ex.getTargetException());
}
}
/* (non-Javadoc)
* @see org.directwebremoting.Container#getBean(java.lang.String)
*/
public Object getBean(String id)
{
Object reply = beans.get(id);
if (reply == null)
{
log.debug("DefaultContainer: No bean with id=" + id);
}
return reply;
}
/* (non-Javadoc)
* @see org.directwebremoting.Container#getBeanNames()
*/
public Collection getBeanNames()
{
return Collections.unmodifiableCollection(beans.keySet());
}
/**
* The beans that we know of indexed by type
*/
protected Map beans = new TreeMap();
/**
* The log stream
*/
private static final Logger log = Logger.getLogger(DefaultContainer.class);
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy