src/main/java/org/apache/maven/plugins/scripting/EvalMojo.java

/*
 * 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.maven.plugins.scripting;

import javax.script.Bindings;
import javax.script.ScriptException;
import javax.script.SimpleBindings;

import java.io.File;

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugins.annotations.Mojo;
import org.apache.maven.plugins.annotations.Parameter;
import org.apache.maven.project.MavenProject;

/**
 * Evaluate the specified script or scriptFile
 *
 * @author Robert Scholte
 * @since 3.0.0
 */
@Mojo(name = "eval")
public class EvalMojo extends AbstractMojo {
    @Parameter
    private String engineName;

    /**
     * When used, also specify the engineName
     */
    @Parameter
    private String script;

    /**
     * Provide the script as an external file as an alternative to <script>.
     * When scriptFile provided the script is ignored.
     * The file name extension identifies the script language to use, as of javax.script.ScriptEngineManager
     * and {@linkplain "https://jcp.org/aboutJava/communityprocess/final/jsr223/index.html"}
     */
    @Parameter
    private File scriptFile;

    @Parameter
    String scriptResource;

    // script variables
    @Parameter(defaultValue = "${project}", readonly = true)
    private MavenProject project;

    @Override
    public void execute() throws MojoExecutionException, MojoFailureException {
        try {
            AbstractScriptEvaluator execute = constructExecute();

            Bindings bindings = new SimpleBindings();
            bindings.put("project", project);
            bindings.put("log", getLog());

            Object result = execute.eval(bindings, getLog());

            getLog().info("Result:");
            if (result != null) {
                getLog().info(result.toString());
            }
        } catch (ScriptException e) // configuring the plugin failed
        {
            throw new MojoExecutionException(e.getMessage(), e);
        } catch (UnsupportedScriptEngineException e) // execution failure
        {
            throw new MojoFailureException(e.getMessage(), e);
        }
    }

    private AbstractScriptEvaluator constructExecute() throws IllegalArgumentException {
        AbstractScriptEvaluator execute;

        if (scriptFile != null) {
            execute = new FileScriptEvaluator(engineName, scriptFile);

        } else if (scriptResource != null) {
            execute = new ResourceScriptEvaluator(engineName, scriptResource);

        } else if (script != null) {
            execute = new StringScriptEvaluator(engineName, script);

        } else {
            throw new IllegalArgumentException("Missing script or scriptFile provided");
        }
        return execute;
    }
}