#4: Add (deactivated) functionality to write execAndSave()-dumps to a…

… directory

Since this only one piece for the directory support, it is not activated for use in the command line tool or UI.

src/main/java/jdump/dump/Configuration.java

@@ -1,5 +1,7 @@
 package jdump.dump;
 
+import jdump.output.Output;
+
 import java.time.Duration;
 
 /**
@@ -15,6 +17,7 @@ public class Configuration {
     private Duration jfrDuration = JFRDump.DEFAULT_JFR_DURATION;
     private boolean wantNmtForAll = false;
     private String outputDirectory = System.getProperty("user.dir");
+    private Output.TYPE outputType = Output.TYPE.FILE;
 
     private Configuration() {}
 
@@ -25,6 +28,8 @@ private Configuration(Configuration configuration) {
         this.jfrDuration = configuration.jfrDuration;
         this.wantNmtForAll = configuration.wantNmtForAll;
         this.outputDirectory = configuration.outputDirectory;
+        this.outputType = configuration.outputType ==
+                Output.TYPE.DIRECTORY || moreThanOneDump() ? Output.TYPE.DIRECTORY : Output.TYPE.FILE;
     }
 
     public static class Mutable extends Configuration {
@@ -60,6 +65,24 @@ public void wantAllDumps() {
             super.wantJfrForAll();
             super.wantNmtForAll();
         }
+
+        public Mutable outputDirectory(String directoryName) {
+            super.outputDirectory(directoryName);
+            return this;
+        }
+
+        public Mutable outputType(Output.TYPE outputType) {
+            super.outputType(outputType);
+            return this;
+        }
+    }
+
+    private void outputType(Output.TYPE outputType) {
+        this.outputType = outputType;
+    }
+
+    private void outputDirectory(String directoryName) {
+        this.outputDirectory = directoryName;
     }
 
     private void wantNmtForAll() {
@@ -106,8 +129,20 @@ public Duration jfrDuration() {
         return jfrDuration;
     }
 
+    public Output.TYPE outputType() {
+        return outputType;
+    }
+
     static Configuration defaultConfiguration() {
         return new Configuration();
     }
 
+    private boolean moreThanOneDump() {
+        int numberOfDumpTypes = 0;
+        if (wantHeapDumpForAll) numberOfDumpTypes++;
+        if (wantThreadDumpForAll) numberOfDumpTypes++;
+        if (wantJFRForAll) numberOfDumpTypes++;
+        if (wantNmtForAll) numberOfDumpTypes++;
+        return numberOfDumpTypes > 1;
+    }
 }

src/main/java/jdump/dump/HotspotDump.java

@@ -2,9 +2,9 @@
 
 import com.sun.tools.attach.AttachNotSupportedException;
 import com.sun.tools.attach.VirtualMachineDescriptor;
+import jdump.output.Output;
 import sun.tools.attach.HotSpotVirtualMachine;
 
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
@@ -38,14 +38,15 @@ void execAndPrint(VirtualMachineDescriptor vmd, String command, Object... args)
     /**
      * Executes an Attach API command and writes the returned output to a given file.
      * @param vmd the {@link VirtualMachineDescriptor} describing the JVM to which to send the command
-     * @param outputFile the file to which to write the output
+     * @param output the {@link Output} for persisting the dump
      * @param command the Attach API command to send to the JVM
      * @param args the Arguments for the Attach API command
      */
-    void execAndSave(VirtualMachineDescriptor vmd, File outputFile, String command, Object... args) {
+    void execAndSave(VirtualMachineDescriptor vmd, Output output, String command, Object... args) {
         try {
             InputStream is = executeCommand(vmd, command, args);
-            Files.copy(is, outputFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+            System.out.println("dumping to " + output.path());
+            Files.copy(is, output.path(), StandardCopyOption.REPLACE_EXISTING);
         } catch (Exception e) {
             System.err.println("Failed for JVM " + vmd.id() + ": " + e);
         }

src/main/java/jdump/dump/NMTDump.java

@@ -1,39 +1,31 @@
 package jdump.dump;
 
 import com.sun.tools.attach.VirtualMachineDescriptor;
-
-import java.io.File;
-import java.io.IOException;
-import java.nio.file.Files;
-import java.nio.file.Paths;
+import jdump.output.Output;
 
 /**
  * Supports dumping native memory tracks.
  */
 public class NMTDump extends HotspotDump {
-    private final String outputDirectory;
+    private final Configuration configuration;
 
     NMTDump(Configuration configuration) {
-        this.outputDirectory = configuration.outputDirectory();
+        this.configuration = configuration;
     }
 
     @Override
     void performFor(VirtualMachineDescriptor vmd) {
         System.out.println("Dump NMT for JVM " + vmd.id());
-        execAndSave(vmd, new File(filenameFor(vmd)), "jcmd","VM.native_memory");
-        var path = Paths.get(filenameFor(vmd));
-        try(var lines = Files.lines(path)) {
-            if (lines.anyMatch(line -> line.contains("Native memory tracking is not enabled"))) {
-                System.err.println("Native memory tracking is not enabled for JVM " + vmd.id());
-                Files.delete(path);
-            }
-        } catch (IOException e) {
-            System.err.println("Failure generating NMT dump:" + e.getMessage());
+        var output = Output.using(configuration);
+        execAndSave(vmd, output.file(filenameFor(vmd)), "jcmd","VM.native_memory");
+        if (output.aLineMatches("Native memory tracking is not enabled")) {
+            System.err.println("Native memory tracking is not enabled for JVM " + vmd.id());
+            output.deleteFile();
         }
     }
 
     @Override
     String filenameFor(VirtualMachineDescriptor vmd) {
-        return outputDirectory + File.separator + "jdump-nmt-" + vmd.id() + ".txt";
+        return "jdump-nmt-" + vmd.id() + ".txt";
     }
 }

src/main/java/jdump/dump/ThreadDump.java

@@ -1,27 +1,26 @@
 package jdump.dump;
 
 import com.sun.tools.attach.VirtualMachineDescriptor;
-
-import java.io.File;
+import jdump.output.Output;
 
 /**
  * Supports dumping threads, i.e. stack traces of all running threads.
  */
 class ThreadDump extends HotspotDump {
-    private final String outputDirectory;
+    private final Configuration configuration;
 
     ThreadDump(Configuration configuration) {
-        this.outputDirectory = configuration.outputDirectory();
+        this.configuration = configuration;
     }
 
     @Override
     void performFor(VirtualMachineDescriptor vmd) {
         System.out.println("Dumping threads for JVM " + vmd.id());
-        execAndSave(vmd, new File(filenameFor(vmd)), "threaddump");
+        execAndSave(vmd, Output.using(configuration).file(filenameFor(vmd)), "threaddump");
     }
 
     @Override
     String filenameFor(VirtualMachineDescriptor virtualMachineDescriptor) {
-        return outputDirectory + File.separator + "jdump-threads-" + virtualMachineDescriptor.id() + ".txt";
+        return "jdump-threads-" + virtualMachineDescriptor.id() + ".txt";
     }
 }

src/main/java/jdump/output/DirectoryOutput.java

@@ -0,0 +1,45 @@
+package jdump.output;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class DirectoryOutput implements Output {
+    private final File directory;
+    private File currentFile;
+
+    DirectoryOutput(String dirname) {
+        directory = new File(dirname);
+        if (!directory.mkdirs()) {
+            throw new RuntimeException("Could not create directory " + dirname);
+        }
+        System.out.println("created directory " + directory);
+    }
+
+    @Override
+    public Output file(String filename) {
+        currentFile = new File(directory.getPath() + File.separator + filename);
+        return this;
+    }
+
+    @Override
+    public Path path() {
+        return currentFile.toPath();
+    }
+
+    @Override
+    public boolean aLineMatches(String matchString) {
+        try (var lines = Files.lines(path())) {
+            return lines.anyMatch(line -> line.contains(matchString));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void deleteFile() {
+        currentFile.delete();
+    }
+
+}

src/main/java/jdump/output/FileOutput.java

@@ -0,0 +1,40 @@
+package jdump.output;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class FileOutput implements Output {
+    private File file;
+    private final String directoryName;
+
+    FileOutput(String directoryName) {
+        this.directoryName = directoryName;
+    }
+
+    @Override
+    public FileOutput file(String filename) {
+        file = new File(directoryName + File.separator + filename);
+        return this;
+    }
+
+    @Override
+    public Path path() {
+        return file.toPath();
+    }
+
+    @Override
+    public boolean aLineMatches(String matchString) {
+        try (var lines = Files.lines(path())) {
+            return lines.anyMatch(line -> line.contains(matchString));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public void deleteFile() {
+        file.delete();
+    }
+}

src/main/java/jdump/output/Output.java

@@ -0,0 +1,26 @@
+package jdump.output;
+
+import jdump.dump.Configuration;
+
+import java.nio.file.Path;
+
+public interface Output {
+    Output file(String filename);
+    Path path();
+    boolean aLineMatches(String matchString);
+    void deleteFile();
+
+    static Output using(Configuration configuration) {
+        switch (configuration.outputType()) {
+            case FILE:
+                return new FileOutput(configuration.outputDirectory());
+            case DIRECTORY:
+                return new DirectoryOutput(configuration.outputDirectory());
+            default: throw new RuntimeException("Internal error: could not handle output type");
+        }
+    }
+
+    enum TYPE {
+        FILE, DIRECTORY
+    }
+}

src/test/java/jdump/dump/DirectoryOutputTest.java

@@ -0,0 +1,41 @@
+package jdump.dump;
+
+import jdump.output.Output;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Objects;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeoutException;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class DirectoryOutputTest {
+
+    @Test
+    public void testDirectoryOutput() throws ExecutionException, InterruptedException, TimeoutException, IOException {
+        try (JVM jvm = new JVM("-XX:NativeMemoryTracking=summary")) {
+            var directoryName = System.getProperty("user.dir") + File.separator + "foo";
+            jvm.spawn();
+            var dump = new NMTDump(new Configuration.Mutable()
+                    .outputDirectory(directoryName)
+                    .outputType(Output.TYPE.DIRECTORY)
+                    .makeImmutable());
+            dump.performFor(jvm.descriptor());
+            var path = Path.of(directoryName);
+            assertTrue(Files.exists(path), "Folder " + directoryName + "was created");
+            int filesDeleted = 0;
+            for (File file : Objects.requireNonNull(path.toFile().listFiles())) {
+                Files.delete(file.toPath());
+                filesDeleted++;
+            }
+            assertEquals(1, filesDeleted, "One file was created");
+            Files.delete(path);
+        }
+    }
+}
+