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/*

 * @test TestG1ConcRefinementThreads

 * @key gc

 * @bug 8047976

 * @summary Tests argument processing for G1ConcRefinementThreads

 * @library /testlibrary

 * @modules java.base/sun.misc

 *          java.management

 */

import jdk.test.lib.*;

import java.util.*;

import java.util.regex.*;

public class TestG1ConcRefinementThreads {

  static final int AUTO_SELECT_THREADS_COUNT = 0;

  static final int PASSED_THREADS_COUNT = 11;

  public static void main(String args[]) throws Exception {

    // default case

    runG1ConcRefinementThreadsTest(

        new String[]{}, // automatically selected

        AUTO_SELECT_THREADS_COUNT /* use default setting */);

    // zero setting case

    runG1ConcRefinementThreadsTest(

        new String[]{"-XX:G1ConcRefinementThreads=0"}, // automatically selected

        AUTO_SELECT_THREADS_COUNT /* set to zero */);

    // non-zero sestting case

    runG1ConcRefinementThreadsTest(

        new String[]{"-XX:G1ConcRefinementThreads="+Integer.toString(PASSED_THREADS_COUNT)},

        PASSED_THREADS_COUNT);

  }

  private static void runG1ConcRefinementThreadsTest(String[] passedOpts,

          int expectedValue) throws Exception {

    List<String> vmOpts = new ArrayList<>();

    if (passedOpts.length > 0) {

      Collections.addAll(vmOpts, passedOpts);

    }

    Collections.addAll(vmOpts, "-XX:+UseG1GC", "-XX:+PrintFlagsFinal", "-version");

    ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(vmOpts.toArray(new String[vmOpts.size()]));

    OutputAnalyzer output = new OutputAnalyzer(pb.start());

    output.shouldHaveExitValue(0);

    String stdout = output.getStdout();

    checkG1ConcRefinementThreadsConsistency(stdout, expectedValue);

  }

  private static void checkG1ConcRefinementThreadsConsistency(String output, int expectedValue) {

    int actualValue = getIntValue("G1ConcRefinementThreads", output);

    if (expectedValue == 0) {

      // If expectedValue is automatically selected, set it same as ParallelGCThreads.

      expectedValue = getIntValue("ParallelGCThreads", output);

    }

    if (expectedValue != actualValue) {

      throw new RuntimeException(

            "Actual G1ConcRefinementThreads(" + Integer.toString(actualValue)

            + ") is not equal to expected value(" + Integer.toString(expectedValue) + ")");

    }

  }

  public static int getIntValue(String flag, String where) {

    Matcher m = Pattern.compile(flag + "\\s+:?=\\s+\\d+").matcher(where);

    if (!m.find()) {

      throw new RuntimeException("Could not find value for flag " + flag + " in output string");

    }

    String match = m.group();

    return Integer.parseInt(match.substring(match.lastIndexOf(" ") + 1, match.length()));

  }

}