refactor: extract BaseProcessHandler for reusability

Author: metacosm

backend/src/main/java/net/laprun/sustainability/power/nuprocess/BaseProcessHandler.java

@@ -0,0 +1,93 @@
+package net.laprun.sustainability.power.nuprocess;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import com.zaxxer.nuprocess.NuAbstractProcessHandler;
+import com.zaxxer.nuprocess.NuProcess;
+
+public class BaseProcessHandler extends NuAbstractProcessHandler {
+    private String errorMsg;
+    private NuProcess process;
+    private final String[] command;
+    private final GrowableBuffer stdOutBuffer = new GrowableBuffer();
+    private final CompletableFuture<InputStream> output = new CompletableFuture<>();
+
+    public BaseProcessHandler(String... command) {
+        if (command == null || command.length == 0) {
+            throw new IllegalArgumentException("No command specified");
+        }
+        this.command = initCommand(command);
+    }
+
+    protected String[] initCommand(String... command) {
+        return command;
+    }
+
+    public String[] command() {
+        return command;
+    }
+
+    @Override
+    public void onPreStart(NuProcess nuProcess) {
+        this.process = nuProcess;
+    }
+
+    @Override
+    public void onExit(int statusCode) {
+        if (Integer.MIN_VALUE == statusCode) {
+            throw new IllegalArgumentException("Unknown command " + Arrays.toString(command));
+        }
+        if (statusCode != 0) {
+            throw new RuntimeException("Couldn't execute command " + Arrays.toString(command)
+                    + ". Error code: " + statusCode + ", message: " + errorMsg);
+        }
+    }
+
+    public void stop() {
+        if (process.isRunning()) {
+            process.destroy(false);
+            try {
+                process.waitFor(5, TimeUnit.SECONDS);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            } finally {
+                process.destroy(true);
+            }
+        }
+    }
+
+    @Override
+    public void onStdout(ByteBuffer buffer, boolean closed) {
+        if (buffer.hasRemaining()) {
+            stdOutBuffer.put(buffer);
+        }
+
+        if (closed) {
+            output.complete(new ByteArrayInputStream(stdOutBuffer.array()));
+        }
+    }
+
+    @Override
+    public void onStderr(ByteBuffer buffer, boolean closed) {
+        if (!closed) {
+            byte[] bytes = new byte[buffer.remaining()];
+            buffer.get(bytes);
+            errorMsg = new String(bytes);
+        }
+        super.onStderr(buffer, closed);
+    }
+
+    public Future<InputStream> getInputStream() {
+        return output;
+    }
+
+    public boolean isRunning() {
+        return process != null && process.isRunning();
+    }
+}

backend/src/main/java/net/laprun/sustainability/power/sensors/macos/powermetrics/GrowableBuffer.java renamed to backend/src/main/java/net/laprun/sustainability/power/nuprocess/GrowableBuffer.java

@@ -1,4 +1,4 @@
-package net.laprun.sustainability.power.sensors.macos.powermetrics;
+package net.laprun.sustainability.power.nuprocess;
 
 import java.nio.ByteBuffer;
 

backend/src/main/java/net/laprun/sustainability/power/sensors/macos/powermetrics/PowermetricsProcessHandler.java

@@ -1,95 +1,20 @@
 package net.laprun.sustainability.power.sensors.macos.powermetrics;
 
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
-import java.nio.ByteBuffer;
-import java.util.Arrays;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.Future;
-import java.util.concurrent.TimeUnit;
-
-import com.zaxxer.nuprocess.NuAbstractProcessHandler;
-import com.zaxxer.nuprocess.NuProcess;
-
-public class PowermetricsProcessHandler extends NuAbstractProcessHandler {
-    private String errorMsg;
-    private NuProcess process;
-    private final String[] command;
-    private final GrowableBuffer stdOutBuffer = new GrowableBuffer();
-    private final CompletableFuture<InputStream> output = new CompletableFuture<>();
+import net.laprun.sustainability.power.nuprocess.BaseProcessHandler;
 
+public class PowermetricsProcessHandler extends BaseProcessHandler {
     public PowermetricsProcessHandler(String... command) {
-        if (command == null || command.length == 0) {
-            throw new IllegalArgumentException("No powermetrics options specified");
-        }
+        super(command);
+    }
+
+    @Override
+    protected String[] initCommand(String... command) {
         final var additionalArgsCardinality = 3;
         final var args = new String[command.length + additionalArgsCardinality];
         args[0] = "sudo";
         args[1] = "powermetrics";
         args[2] = "--samplers";
         System.arraycopy(command, 0, args, additionalArgsCardinality, command.length);
-        this.command = args;
-    }
-
-    public String[] command() {
-        return command;
-    }
-
-    @Override
-    public void onPreStart(NuProcess nuProcess) {
-        this.process = nuProcess;
-    }
-
-    @Override
-    public void onExit(int statusCode) {
-        if (Integer.MIN_VALUE == statusCode) {
-            throw new IllegalArgumentException("Unknown command " + Arrays.toString(command));
-        }
-        if (statusCode != 0) {
-            throw new RuntimeException("Couldn't execute command " + Arrays.toString(command)
-                    + ". Error code: " + statusCode + ", message: " + errorMsg);
-        }
-    }
-
-    public void stop() {
-        if (process.isRunning()) {
-            process.destroy(false);
-            try {
-                process.waitFor(5, TimeUnit.SECONDS);
-            } catch (InterruptedException e) {
-                throw new RuntimeException(e);
-            } finally {
-                process.destroy(true);
-            }
-        }
-    }
-
-    @Override
-    public void onStdout(ByteBuffer buffer, boolean closed) {
-        if (buffer.hasRemaining()) {
-            stdOutBuffer.put(buffer);
-        }
-
-        if (closed) {
-            output.complete(new ByteArrayInputStream(stdOutBuffer.array()));
-        }
-    }
-
-    @Override
-    public void onStderr(ByteBuffer buffer, boolean closed) {
-        if (!closed) {
-            byte[] bytes = new byte[buffer.remaining()];
-            buffer.get(bytes);
-            errorMsg = new String(bytes);
-        }
-        super.onStderr(buffer, closed);
-    }
-
-    public Future<InputStream> getInputStream() {
-        return output;
-    }
-
-    public boolean isRunning() {
-        return process != null && process.isRunning();
+        return args;
     }
 }