src/main/java/org/apache/maven/plugins/help/SystemMojo.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.help;

import javax.inject.Inject;

import java.io.IOException;
import java.util.Properties;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.annotations.Mojo;
import org.apache.maven.project.ProjectBuilder;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.cli.CommandLineUtils;
import org.eclipse.aether.RepositorySystem;

/**
 * Displays a list of the platform details like system properties and environment variables.
 *
 * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
 * @since 2.1
 */
@Mojo(name = "system", requiresProject = false)
public class SystemMojo extends AbstractHelpMojo {

    @Inject
    public SystemMojo(ProjectBuilder projectBuilder, RepositorySystem repositorySystem) {
        super(projectBuilder, repositorySystem);
    }

    /** Magic number to beautify the output */
    private static final int REPEAT = 25;

    // ----------------------------------------------------------------------
    // Public methods
    // ----------------------------------------------------------------------

    /** {@inheritDoc} */
    @Override
    public void execute() throws MojoExecutionException {
        StringBuilder message = new StringBuilder();

        message.append(LS);
        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);
        message.append(StringUtils.repeat("=", REPEAT));
        message.append(" Platform Properties Details ");
        message.append(StringUtils.repeat("=", REPEAT)).append(LS);
        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);
        message.append(LS);

        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);
        message.append("System Properties").append(LS);
        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);

        Properties systemProperties = System.getProperties();
        for (String key : systemProperties.stringPropertyNames()) {
            message.append(LS);
            message.append(key).append("=").append(systemProperties.getProperty(key));
        }

        message.append(LS).append(LS);
        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);
        message.append("Environment Variables").append(LS);
        message.append(StringUtils.repeat("=", LINE_LENGTH)).append(LS);
        Properties envVars = CommandLineUtils.getSystemEnvVars();
        for (String key : envVars.stringPropertyNames()) {
            message.append(LS);
            message.append(key).append("=").append(envVars.getProperty(key));
        }

        message.append(LS);

        if (output != null) {
            StringBuilder sb = new StringBuilder();
            sb.append("Generated by Maven Help Plugin").append(LS);
            sb.append("See: https://maven.apache.org/plugins/maven-help-plugin/")
                    .append(LS)
                    .append(LS);
            sb.append(message.toString());

            try {
                writeFile(output, sb);
            } catch (IOException e) {
                throw new MojoExecutionException("Cannot write system report to output: " + output, e);
            }

            getLog().info("System report written to: " + output);
        } else {
            getLog().info(message);
        }
    }
}