src/main/java/org/apache/maven/plugins/jlink/JLinkExecutor.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.jlink;

/*
 * 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.
 */

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.List;
import java.util.Optional;
import java.util.spi.ToolProvider;

import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.logging.Log;
import org.apache.maven.toolchain.Toolchain;

/**
 * JDK9+ executor for jlink.
 *
 * <p>This implementation uses the JDK9+ Toolprovider SPI to find and execute jlink.
 * This way, no fork needs to be created.</p>
 */
class JLinkExecutor extends AbstractJLinkToolchainExecutor {
    private final ToolProvider toolProvider;

    JLinkExecutor(Toolchain toolchain, Log log) {
        super(toolchain, log);
        this.toolProvider = getJLinkExecutable();
    }

    protected final ToolProvider getJLinkExecutable() {
        return ToolProvider.findFirst("jlink").orElseThrow(() -> new IllegalStateException("No jlink tool found."));
    }

    @Override
    public int executeJlink(List<String> jlinkArgs) throws MojoExecutionException {
        if (getToolchain().isPresent()) {
            return super.executeJlink(jlinkArgs);
        }

        if (getLog().isDebugEnabled()) {
            // no quoted arguments ???
            getLog().debug(this.toolProvider.name() + " " + jlinkArgs);
        }

        try (StringWriter strErr = new StringWriter();
                PrintWriter err = new PrintWriter(strErr);
                StringWriter strOut = new StringWriter();
                PrintWriter out = new PrintWriter(strOut)) {
            int exitCode = this.toolProvider.run(out, err, jlinkArgs.toArray(new String[0]));
            out.flush();
            err.flush();

            String outAsString = strOut.toString();
            String output = outAsString.isBlank() ? null : '\n' + outAsString.trim();

            if (exitCode != 0) {
                if (output != null && !output.isBlank()) {
                    // Reconsider to use WARN / ERROR ?
                    //  getLog().error( output );
                    for (String outputLine : output.split("\n")) {
                        getLog().error(outputLine);
                    }
                }

                StringBuilder msg = new StringBuilder("\nExit code: ");
                msg.append(exitCode);
                String errAsString = strErr.toString();
                if (errAsString != null && !errAsString.isBlank()) {
                    msg.append(" - ").append(errAsString);
                }
                msg.append('\n');
                msg.append("Command line was: ")
                        .append(this.toolProvider.name())
                        .append(' ')
                        .append(jlinkArgs)
                        .append('\n')
                        .append('\n');

                throw new MojoExecutionException(msg.toString());
            }

            if (output != null && !output.isBlank()) {
                // getLog().info( output );
                for (String outputLine : output.split("\n")) {
                    getLog().info(outputLine);
                }
            }

            return exitCode;
        } catch (IOException e) {
            throw new MojoExecutionException("Unable to execute jlink command: " + e.getMessage(), e);
        }
    }

    @Override
    public Optional<File> getJmodsFolder(/* nullable */ File sourceJdkModules) {
        if (getToolchain().isPresent()) {
            return super.getJmodsFolder(sourceJdkModules);
        }

        if (sourceJdkModules != null && sourceJdkModules.isDirectory()) {
            return Optional.of(new File(sourceJdkModules, JMODS));
        }

        // ToolProvider does not need jmods folder to be set.
        return Optional.empty();
    }
}