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 java.io.Serializable;
022import java.util.Map;
023
024import org.mvel2.MVEL;
025import org.mvel2.compiler.BlankLiteral;
026import org.nuxeo.ecm.automation.OperationContext;
027
028/**
029 * @author <a href="mailto:[email protected]">Bogdan Stefanescu</a>
030 */
031public class MvelExpression implements Expression {
032
033    private static final long serialVersionUID = 1L;
034
035    protected transient volatile Serializable compiled;
036
037    protected final String expr;
038
039    public MvelExpression(String expr) {
040        this.expr = expr;
041    }
042
043    @Override
044    public Object eval(OperationContext ctx) {
045        if (compiled == null) {
046            compiled = MVEL.compileExpression(expr);
047        }
048        Object result = MVEL.executeExpression(compiled, getBindings(ctx));
049
050        return result != null && result.getClass().isAssignableFrom(BlankLiteral.class) ? "" : result;
051    }
052
053    @Override
054    public String getExpr() {
055        return expr;
056    }
057
058    /**
059     * @since 5.9.3
060     */
061    protected Map<String, Object> getBindings(OperationContext ctx) {
062        return Scripting.initBindings(ctx);
063    }
064}