| /* |
| * Copyright 1999,2004 The Apache Software Foundation. |
| * |
| * 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 joran.calculator; |
| |
| import org.apache.log4j.joran.action.Action; |
| import org.apache.log4j.joran.spi.ExecutionContext; |
| import org.apache.log4j.spi.ErrorItem; |
| |
| import org.xml.sax.Attributes; |
| |
| import java.util.EmptyStackException; |
| |
| |
| /** |
| * |
| * This action multiplies the two integers at the top of the stack (they are removed) |
| * and pushes the result on top the stack. |
| * |
| * @author Ceki Gülcü |
| */ |
| public class MultiplyAction extends Action { |
| |
| |
| public void begin(ExecutionContext ec, String name, Attributes attributes) { |
| int first = fetchInteger(ec); |
| int second = fetchInteger(ec); |
| ec.pushObject(new Integer(first * second)); |
| } |
| |
| /** |
| * Pop the Integer object at the top of the stack. |
| * This code illustrates usage of Joran's error handling paradigm. |
| */ |
| int fetchInteger(ExecutionContext ec) { |
| int result = 0; |
| |
| try { |
| Object o1 = ec.popObject(); |
| |
| if (o1 instanceof Integer) { |
| result = ((Integer) o1).intValue(); |
| } else { |
| String errMsg = |
| "Object [" + o1 |
| + "] currently at the top of the stack is not an integer."; |
| ec.addError(new ErrorItem(errMsg)); |
| throw new IllegalArgumentException(errMsg); |
| } |
| } catch (EmptyStackException ese) { |
| ec.addError( |
| new ErrorItem("Expecting an integer on the execution stack.")); |
| throw ese; |
| } |
| return result; |
| } |
| |
| public void end(ExecutionContext ec, String name) { |
| // Nothing to do here. |
| // In general, the end() method of actions associated with elements |
| // having no children do not need to perform any processing in their |
| // end() method. |
| } |
| } |