001package org.apache.maven.plugins.enforcer;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
023import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
024import org.apache.maven.plugin.logging.Log;
025import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
026import org.codehaus.plexus.util.StringUtils;
027
028import bsh.EvalError;
029import bsh.Interpreter;
030
031/**
032 * Rule for Maven Enforcer using Beanshell to evaluate a conditional expression.
033 *
034 * @author hugonnem
035 */
036public class EvaluateBeanshell
037    extends AbstractNonCacheableEnforcerRule
038{
039
040    /** Beanshell interpreter. */
041    private static final Interpreter BSH = new Interpreter();
042
043    /** The condition to be evaluated.
044     *  
045     * @see {@link #setCondition(String)}
046     * @see {@link #getCondition()}
047     * */
048    private String condition;
049
050    public final void setCondition( String condition )
051    {
052        this.condition = condition;
053    }
054    
055    public final String getCondition()
056    {
057        return condition;
058    }
059
060    /*
061     * (non-Javadoc)
062     *
063     * @see org.apache.maven.enforcer.rule.api.EnforcerRule#execute(org.apache.maven.enforcer.rule.api.EnforcerRuleHelper)
064     */
065    public void execute( EnforcerRuleHelper helper )
066        throws EnforcerRuleException
067    {
068        Log log = helper.getLog();
069
070        try
071        {
072            log.debug( "Echo condition : " + this.condition );
073            // Evaluate condition within Plexus Container
074            String script = (String) helper.evaluate( this.condition );
075            log.debug( "Echo script : " + script );
076            if ( !evaluateCondition( script, log ) )
077            {
078                String message = getMessage();
079                if ( StringUtils.isEmpty( message ) )
080                {
081                    message = "The expression \"" + condition + "\" is not true.";
082                }
083                throw new EnforcerRuleException( message );
084            }
085        }
086        catch ( ExpressionEvaluationException e )
087        {
088            throw new EnforcerRuleException( "Unable to evaluate an expression '" + condition + "'", e );
089        }
090    }
091
092    /**
093     * Evaluate expression using Beanshell.
094     *
095     * @param script the expression to be evaluated
096     * @param log the logger
097     * @return boolean the evaluation of the expression
098     * @throws EnforcerRuleException if the script could not be evaluated
099     */
100    protected boolean evaluateCondition( String script, Log log )
101        throws EnforcerRuleException
102    {
103        Boolean evaluation = Boolean.FALSE;
104        try
105        {
106            evaluation = (Boolean) BSH.eval( script );
107            log.debug( "Echo evaluating : " + evaluation );
108        }
109        catch ( EvalError ex )
110        {
111            throw new EnforcerRuleException( "Couldn't evaluate condition: " + script, ex );
112        }
113        return evaluation.booleanValue();
114    }
115}