/**
* LOGBack: the generic, reliable, fast and flexible logging framework.
*
* Copyright (C) 1999-2006, QOS.ch
*
* This library 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.
*/
package ch.qos.logback.core.joran.action;
import java.util.Stack;
import org.xml.sax.Attributes;
import ch.qos.logback.core.joran.spi.InterpretationContext;
import ch.qos.logback.core.joran.spi.Pattern;
import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.LifeCycle;
import ch.qos.logback.core.util.ContainmentType;
import ch.qos.logback.core.util.Loader;
import ch.qos.logback.core.util.OptionHelper;
import ch.qos.logback.core.util.PropertySetter;
/**
* This action is responsible for tying together a parent object with a child
* element for which there is no explicit rule.
*
* @author Ceki Gülcü
*/
public class NestedComponentIA extends ImplicitAction {
// actionDataStack contains ActionData instances
// We use a stack of ActionData objects in order to support nested
// elements which are handled by the same NestComponentIA instance.
// We push a ActionData instance in the isApplicable method (if the
// action is applicable) and pop it in the end() method.
// The XML well-formedness property will guarantee that a push will eventually
// be followed by the corresponding pop.
Stack<ImplicitActionData> actionDataStack = new Stack<ImplicitActionData>();
public boolean isApplicable(Pattern pattern, Attributes attributes,
InterpretationContext ec) {
// System.out.println("in NestComponentIA.isApplicable [" + pattern + "]");
String nestedElementTagName = pattern.peekLast();
// calling ec.peekObject with an empty stack will throw an exception
if (ec.isEmpty()) {
return false;
}
Object o = ec.peekObject();
PropertySetter parentBean = new PropertySetter(o);
parentBean.setContext(context);
ContainmentType containmentType = parentBean
.canContainComponent(nestedElementTagName);
switch (containmentType) {
case NOT_FOUND:
case AS_SINGLE_PROPERTY:
case AS_PROPERTY_COLLECTION:
return false;
// we only push action data if NestComponentIA is applicable
case AS_COMPONENT_COLLECTION:
case AS_SINGLE_COMPONENT:
//addInfo("was deemed applicable for " + pattern);
ImplicitActionData ad = new ImplicitActionData(parentBean,
containmentType);
actionDataStack.push(ad);
return true;
default:
addError("PropertySetter.canContainComponent returned " + containmentType);
return false;
}
}
public void begin(InterpretationContext ec, String localName,
Attributes attributes) {
// LogLog.debug("in NestComponentIA begin method");
// get the action data object pushed in isApplicable() method call
ImplicitActionData actionData = (ImplicitActionData) actionDataStack.peek();
String className = attributes.getValue(CLASS_ATTRIBUTE);
// perform variable name substitution
className = ec.subst(className);
if (OptionHelper.isEmpty(className)) {
actionData.inError = true;
String errMsg = "No class name attribute in [" + localName + "]";
addError(errMsg);
return;
}
try {
// getLogger().debug(
// "About to instantiate component [{}] of type [{}]", localName,
// className);
// FIXME: Loading classes should be governed by config file rules.
actionData.nestedComponent = Loader.loadClass(className, context).newInstance();
// pass along the repository
if (actionData.nestedComponent instanceof ContextAware) {
((ContextAware) actionData.nestedComponent).setContext(this.context);
}
// getLogger().debug(
addInfo("Pushing component [" + localName
+ "] on top of the object stack.");
ec.pushObject(actionData.nestedComponent);
} catch (Exception oops) {
actionData.inError = true;
String msg = "Could not create component [" + localName + "] of type ["
+ className + "]";
addError(msg, oops);
}
}
public void end(InterpretationContext ec, String tagName) {
// pop the action data object pushed in isApplicable() method call
// we assume that each this begin
ImplicitActionData actionData = (ImplicitActionData) actionDataStack.pop();
if (actionData.inError) {
return;
}
PropertySetter nestedBean = new PropertySetter(actionData.nestedComponent);
nestedBean.setContext(context);
if (nestedBean.canContainComponent("parent") == ContainmentType.AS_SINGLE_COMPONENT) {
nestedBean.setComponent("parent", actionData.parentBean.getObj());
}
if (actionData.nestedComponent instanceof LifeCycle) {
((LifeCycle) actionData.nestedComponent).start();
}
Object o = ec.peekObject();
if (o != actionData.nestedComponent) {
addError("The object on the top the of the stack is not the component pushed earlier.");
} else {
// getLogger().debug("Removing component from the object stack");
ec.popObject();
// Now let us attach the component
switch (actionData.containmentType) {
case AS_SINGLE_COMPONENT:
// addInfo("Setting ["+tagName+"}] to parent of type
// ["+actionData.parentBean.getObjClass()+"]");
actionData.parentBean.setComponent(tagName, actionData.nestedComponent);
break;
case AS_COMPONENT_COLLECTION:
// getLogger().debug(
// "Adding [{}] to parent of type [{}]", tagName,
// actionData.parentBean.getObjClass());
actionData.parentBean.addComponent(tagName, actionData.nestedComponent);
break;
}
}
}
}