Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, 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.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, 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 ch.qos.logback.core.joran.action.ActionUtil.Scope;
import ch.qos.logback.core.joran.spi.InterpretationContext;
import ch.qos.logback.core.joran.spi.ActionException;
import ch.qos.logback.core.spi.LifeCycle;
import ch.qos.logback.core.util.OptionHelper;
import ch.qos.logback.core.spi.PropertyDefiner;
import org.xml.sax.Attributes;

Instantiate class for define property value. Get future property name and
property definer class from attributes. Some property definer properties
could be used. After defining put new property to context.
Author:
Aleksey Didik/**
 * Instantiate class for define property value. Get future property name and
 * property definer class from attributes. Some property definer properties
 * could be used. After defining put new property to context.
 * 
 * @author Aleksey Didik
 */
public class DefinePropertyAction extends Action {

    String scopeStr;
    Scope scope;
    String propertyName;
    PropertyDefiner definer;
    boolean inError;

    public void begin(InterpretationContext ec, String localName, Attributes attributes) throws ActionException {
        // reset variables
        scopeStr = null;
        scope = null;
        propertyName = null;
        definer = null;
        inError = false;

        // read future property name
        propertyName = attributes.getValue(NAME_ATTRIBUTE);
        scopeStr = attributes.getValue(SCOPE_ATTRIBUTE);

        scope = ActionUtil.stringToScope(scopeStr);
        if (OptionHelper.isEmpty(propertyName)) {
            addError("Missing property name for property definer. Near [" + localName + "] line " + getLineNumber(ec));
            inError = true;
            return;
        }

        // read property definer class name
        String className = attributes.getValue(CLASS_ATTRIBUTE);
        if (OptionHelper.isEmpty(className)) {
            addError("Missing class name for property definer. Near [" + localName + "] line " + getLineNumber(ec));
            inError = true;
            return;
        }

        // try to instantiate property definer
        try {
            addInfo("About to instantiate property definer of type [" + className + "]");
            definer = (PropertyDefiner) OptionHelper.instantiateByClassName(className, PropertyDefiner.class, context);
            definer.setContext(context);
            if (definer instanceof LifeCycle) {
                ((LifeCycle) definer).start();
            }
            ec.pushObject(definer);
        } catch (Exception oops) {
            inError = true;
            addError("Could not create an PropertyDefiner of type [" + className + "].", oops);
            throw new ActionException(oops);
        }
    }

    
Now property definer is initialized by all properties and we can put
property value to context
/**
     * Now property definer is initialized by all properties and we can put
     * property value to context
     */
    public void end(InterpretationContext ec, String name) {
        if (inError) {
            return;
        }

        Object o = ec.peekObject();

        if (o != definer) {
            addWarn("The object at the of the stack is not the property definer for property named [" + propertyName + "] pushed earlier.");
        } else {
            addInfo("Popping property definer for property named [" + propertyName + "] from the object stack");
            ec.popObject();
            // let's put defined property and value to context but only if it is
            // not null
            String propertyValue = definer.getPropertyValue();
            if (propertyValue != null) {
                ActionUtil.setProperty(ec, propertyName, propertyValue, scope);
            }
        }
    }
}