/*
* Copyright 2008 biaoping.yin
*
* 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.frameworkset.spi.support;
import org.apache.log4j.Logger;
import org.frameworkset.spi.ApplicationContextException;
import org.frameworkset.spi.BaseApplicationContext;
import com.frameworkset.spi.assemble.BeanInstanceException;
/**
* <p>Title: ApplicationObjectSupport.java</p>
* <p>Description: </p>
* <p>bboss workgroup</p>
* <p>Copyright (c) 2007</p>
* @Date 2010-9-24 下午04:51:39
* @author biaoping.yin
* @version 1.0
*/
public class ApplicationObjectSupport {
/** Logger that is available to subclasses */
protected static final Logger logger = Logger.getLogger(ApplicationObjectSupport.class);
/** ApplicationContext this object runs in */
private BaseApplicationContext applicationContext;
/** MessageSourceAccessor for easy message access */
private MessageSourceAccessor messageSourceAccessor;
public final void setApplicationContext(BaseApplicationContext context) throws BeanInstanceException {
if (context == null && !isContextRequired()) {
// Reset internal context state.
this.applicationContext = null;
this.messageSourceAccessor = null;
}
else if (this.applicationContext == null) {
// Initialize with passed-in context.
if (!requiredContextClass().isInstance(context)) {
throw new ApplicationContextException(
"Invalid application context: needs to be of type [" + requiredContextClass().getName() + "]");
}
this.applicationContext = context;
this.messageSourceAccessor = new MessageSourceAccessor(context);
initApplicationContext(context);
}
else {
// Ignore reinitialization if same context passed in.
if (this.applicationContext != context) {
throw new ApplicationContextException(
"Cannot reinitialize with different application context: current one is [" +
this.applicationContext + "], passed-in one is [" + context + "]");
}
}
}
/**
* Determine whether this application object needs to run in an ApplicationContext.
* <p>Default is "false". Can be overridden to enforce running in a context
* (i.e. to throw IllegalStateException on accessors if outside a context).
* @see #getApplicationContext
* @see #getMessageSourceAccessor
*/
protected boolean isContextRequired() {
return false;
}
/**
* Determine the context class that any context passed to
* <code>setApplicationContext</code> must be an instance of.
* Can be overridden in subclasses.
* @see #setApplicationContext
*/
protected Class requiredContextClass() {
return BaseApplicationContext.class;
}
/**
* Subclasses can override this for custom initialization behavior.
* Gets called by <code>setApplicationContext</code> after setting the context instance.
* <p>Note: Does </i>not</i> get called on reinitialization of the context
* but rather just on first initialization of this object's context reference.
* <p>The default implementation calls the overloaded {@link #initApplicationContext()}
* method without ApplicationContext reference.
* @param context the containing ApplicationContext
* @throws ApplicationContextException in case of initialization errors
* @throws Exception if thrown by ApplicationContext methods
* @see #setApplicationContext
*/
protected void initApplicationContext(BaseApplicationContext context) throws RuntimeException {
initApplicationContext();
}
/**
* Subclasses can override this for custom initialization behavior.
* <p>The default implementation is empty. Called by
* {@link #initApplicationContext(org.frameworkset.spi.ApplicationContext)}.
* @throws ApplicationContextException in case of initialization errors
* @throws Exception if thrown by ApplicationContext methods
* @see #setApplicationContext
*/
protected void initApplicationContext() throws RuntimeException {
}
/**
* Return the ApplicationContext that this object is associated with.
* @throws IllegalStateException if not running in an ApplicationContext
*/
public final BaseApplicationContext getApplicationContext() throws IllegalStateException {
if (this.applicationContext == null && isContextRequired()) {
throw new IllegalStateException(
"ApplicationObjectSupport instance [" + this + "] does not run in an ApplicationContext");
}
return this.applicationContext;
}
/**
* Return a MessageSourceAccessor for the application context
* used by this object, for easy message access.
* @throws IllegalStateException if not running in an ApplicationContext
*/
protected final MessageSourceAccessor getMessageSourceAccessor() throws IllegalStateException {
if (this.messageSourceAccessor == null && isContextRequired()) {
throw new IllegalStateException(
"ApplicationObjectSupport instance [" + this + "] does not run in an ApplicationContext");
}
return this.messageSourceAccessor;
}
}