refactor checksum processing

Author: frankgiordano

src/main/java/zos/shell/controller/container/ControllerFactoryContainer.java

@@ -58,6 +58,7 @@
 public class ControllerFactoryContainer {
 
     private static final Logger LOG = LoggerFactory.getLogger(ControllerFactoryContainer.class);
+    private final CheckSumService checkSumService = new CheckSumService();
     private final EnvVariableController envVariableController = new EnvVariableController(new EnvVariableService());
     private final PathService pathService = new PathService(ConnSingleton.getInstance(), this.envVariableController);
     private final Map<ContainerType.Name, Object> controllers = new HashMap<>();
@@ -240,8 +241,7 @@ public EditController getEditController(final ZosConnection connection, final lo
         if (controller == null || controller.isNotValid(dependency)) {
             var dsnGet = new DsnGet(connection);
             var download = new Download(dsnGet, this.pathService, false);
-            var checkSumService = new CheckSumService();
-            var editService = new EditService(download, this.pathService, checkSumService, timeout);
+            var editService = new EditService(download, this.pathService, this.checkSumService, timeout);
             controller = new EditController(editService, dependency);
             this.controllers.put(ContainerType.Name.EDIT, controller);
         }
@@ -347,8 +347,7 @@ public SaveController getSaveController(final ZosConnection connection, final lo
         var controller = (SaveController) controllers.get(ContainerType.Name.SAVE);
         var dependency = new Dependency.Builder().zosConnection(connection).timeout(timeout).build();
         if (controller == null || controller.isNotValid(dependency)) {
-            var checkSumService = new CheckSumService();
-            var service = new SaveService(new DsnWrite(connection), this.pathService, checkSumService, timeout);
+            var service = new SaveService(new DsnWrite(connection), this.pathService, this.checkSumService, timeout);
             controller = new SaveController(service, dependency);
             this.controllers.put(ContainerType.Name.SAVE, controller);
         }

src/main/java/zos/shell/service/checksum/CheckSumService.java

@@ -2,44 +2,49 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import zos.shell.singleton.CheckSumSingleton;
 
-import java.io.IOException;
-import java.math.BigInteger;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import java.util.HashMap;
+import java.util.Map;
 
 public class CheckSumService {
 
     private static final Logger LOG = LoggerFactory.getLogger(CheckSumService.class);
 
-    private static final CheckSumSingleton checkSumSingleton = CheckSumSingleton.getInstance();
+    private final Map<String, String> checksums = new HashMap<>();
 
     public CheckSumService() {
         LOG.debug("*** CheckSumService ***");
     }
 
     public void addCheckSum(final String target) {
         LOG.debug("*** addCheckSum ***");
-        checkSumSingleton.put(target, calculateCheckSum(target));
+        checksums.put(target, calculateCheckSum(target));
     }
 
     public String getCheckSum(final String target) {
         LOG.debug("*** getCheckSum ***");
-        return checkSumSingleton.get(target);
+        return checksums.get(target);
     }
 
     public String calculateCheckSum(final String target) {
-        LOG.debug("*** calculateCheckSum ***");
-        byte[] hash = new byte[0];
         try {
-            byte[] data = Files.readAllBytes(Paths.get(target));
-            hash = MessageDigest.getInstance("MD5").digest(data);
-        } catch (IOException | NoSuchAlgorithmException ignored) {
+            byte[] fileBytes = Files.readAllBytes(Paths.get(target));
+            MessageDigest md = MessageDigest.getInstance("MD5");
+            byte[] digest = md.digest(fileBytes);
+
+            StringBuilder sb = new StringBuilder();
+            for (byte b : digest) {
+                sb.append(String.format("%02x", b));
+            }
+            return sb.toString();
+
+        } catch (Exception e) {
+            LOG.error("Error calculating checksum for {}", target, e);
+            throw new RuntimeException(e);
         }
-        return new BigInteger(1, hash).toString(16);
     }
 
 }

src/main/java/zos/shell/service/dsn/save/Save.java

@@ -57,7 +57,7 @@ public ResponseStatus save(final String dataset, final String target) {
 
         try (var br = new BufferedReader(new FileReader(this.pathService.getPathWithFile()))) {
             var sb = new StringBuilder();
-            var line = br.readLine();
+            String line = br.readLine();
 
             while (line != null) {
                 sb.append(line);
@@ -66,7 +66,7 @@ public ResponseStatus save(final String dataset, final String target) {
             }
             var content = sb.toString().replaceAll("(\\r)", "");
 
-            var checksum = checkSumService.calculateCheckSum(this.pathService.getPathWithFile());
+            String checksum = checkSumService.calculateCheckSum(this.pathService.getPathWithFile());
             if (checksum.equals(checkSumService.getCheckSum(this.pathService.getPathWithFile()))) {
                 return new ResponseStatus("nothing to save, perform editor save and try again...", false);
             }