001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 */
019package org.nuxeo.ecm.automation.core.scripting;
020
021import org.mvel2.compiler.BlankLiteral;
022import org.mvel2.templates.CompiledTemplate;
023import org.mvel2.templates.TemplateCompiler;
024import org.mvel2.templates.TemplateRuntime;
025import org.nuxeo.ecm.automation.OperationContext;
026
027/**
028 * @author <a href="mailto:[email protected]">Bogdan Stefanescu</a>
029 */
030public class MvelTemplate implements Expression {
031
032    private static final long serialVersionUID = 1L;
033
034    protected transient volatile CompiledTemplate compiled;
035
036    protected final String expr;
037
038    public MvelTemplate(String expr) {
039        this.expr = expr;
040    }
041
042    @Override
043    public Object eval(OperationContext ctx) {
044        if (compiled == null) {
045            compiled = TemplateCompiler.compileTemplate(expr);
046        }
047        Object obj = TemplateRuntime.execute(compiled, Scripting.initBindings(ctx));
048        return obj == null || obj.getClass().isAssignableFrom(BlankLiteral.class) ? "" : obj.toString();
049    }
050
051    @Override
052    public String getExpr() {
053        return expr;
054    }
055
056}