NestedBasicPropertyIA.java

/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.joran.action;

import java.util.Stack;

import ch.qos.logback.core.joran.spi.ElementPath;
import org.xml.sax.Attributes;

import ch.qos.logback.core.joran.spi.InterpretationContext;
import ch.qos.logback.core.joran.util.PropertySetter;
import ch.qos.logback.core.util.AggregationType;

/**
 * This action is responsible for tying together a parent object with one of its
 * <em>simple</em> properties specified as an element but for which there is
 * no explicit rule.
 * 
 * @author Ceki Gülcü
 */
public class NestedBasicPropertyIA extends ImplicitAction {


  // We use a stack of IADataForBasicProperty objects in order to 
  // support nested elements which are handled by the same NestedBasicPropertyIA instance.
  // We push a IADataForBasicProperty 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<IADataForBasicProperty> actionDataStack = new Stack<IADataForBasicProperty>();

  public boolean isApplicable(ElementPath elementPath, Attributes attributes,
      InterpretationContext ec) {
    // System.out.println("in NestedSimplePropertyIA.isApplicable [" + pattern +
    // "]");
    String nestedElementTagName = elementPath.peekLast();

    // no point in attempting if there is no parent object
    if (ec.isEmpty()) {
      return false;
    }

    Object o = ec.peekObject();
    PropertySetter parentBean = new PropertySetter(o);
    parentBean.setContext(context);

    AggregationType aggregationType = parentBean
        .computeAggregationType(nestedElementTagName);

    switch (aggregationType) {
    case NOT_FOUND:
    case AS_COMPLEX_PROPERTY:
    case AS_COMPLEX_PROPERTY_COLLECTION:
      return false;

    case AS_BASIC_PROPERTY:
    case AS_BASIC_PROPERTY_COLLECTION:
      IADataForBasicProperty ad = new IADataForBasicProperty(parentBean,
          aggregationType, nestedElementTagName);
      actionDataStack.push(ad);
      // addInfo("NestedSimplePropertyIA deemed applicable [" + pattern + "]");
      return true;
    default:
      addError("PropertySetter.canContainComponent returned " + aggregationType);
      return false;
    }
  }

  public void begin(InterpretationContext ec, String localName,
      Attributes attributes) {
    // NOP
  }

  public void body(InterpretationContext ec, String body) {

    String finalBody = ec.subst(body);
    // get the action data object pushed in isApplicable() method call
    IADataForBasicProperty actionData = (IADataForBasicProperty) actionDataStack.peek();
    switch (actionData.aggregationType) {
    case AS_BASIC_PROPERTY:
      actionData.parentBean.setProperty(actionData.propertyName, finalBody);
      break;
    case AS_BASIC_PROPERTY_COLLECTION:
      actionData.parentBean
          .addBasicProperty(actionData.propertyName, finalBody);
    }
  }

  public void end(InterpretationContext ec, String tagName) {
    // pop the action data object pushed in isApplicable() method call
    actionDataStack.pop();
  }
}