| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.commons.jelly.tags.bsf; |
| |
| import org.apache.bsf.BSFEngine; |
| import org.apache.bsf.BSFManager; |
| |
| import java.util.Iterator; |
| |
| import org.apache.commons.jelly.JellyContext; |
| import org.apache.commons.jelly.expression.ExpressionSupport; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| |
| /** Represents a BSF expression |
| * |
| * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> |
| * @version $Revision$ |
| */ |
| public class BSFExpression extends ExpressionSupport { |
| |
| /** The Log to which logging calls will be made. */ |
| private static final Log log = LogFactory.getLog( BSFExpression.class ); |
| |
| /** The expression */ |
| private String text; |
| |
| /** The BSF Engine to evaluate expressions */ |
| private BSFEngine engine; |
| /** The BSF Manager to evaluate expressions */ |
| private BSFManager manager; |
| |
| /** The adapter to BSF's ObjectRegistry that uses the JellyContext */ |
| private JellyContextRegistry registry; |
| |
| public BSFExpression(String text, BSFEngine engine, BSFManager manager, JellyContextRegistry registry) { |
| this.text = text; |
| this.engine = engine; |
| this.manager = manager; |
| this.registry = registry; |
| } |
| |
| // Expression interface |
| //------------------------------------------------------------------------- |
| public String getExpressionText() { |
| return "${" + text + "}"; |
| } |
| |
| public Object evaluate(JellyContext context) { |
| // XXXX: unfortunately we must synchronize evaluations |
| // so that we can swizzle in the context. |
| // maybe we could create an expression from a context |
| // (and so create a BSFManager for a context) |
| synchronized (registry) { |
| registry.setJellyContext(context); |
| |
| try { |
| // XXXX: hack - there must be a better way!!! |
| for ( Iterator iter = context.getVariableNames(); iter.hasNext(); ) { |
| String name = (String) iter.next(); |
| Object value = context.getVariable( name ); |
| manager.declareBean( name, value, value.getClass() ); |
| } |
| return engine.eval( text, -1, -1, text ); |
| } |
| catch (Exception e) { |
| log.warn( "Caught exception evaluating: " + text + ". Reason: " + e, e ); |
| return null; |
| } |
| } |
| } |
| } |