Add new terminal components and tooling settings

src/main/java/dev/jakub/terminal/components/SysInfo.java

@@ -0,0 +1,53 @@
+package dev.jakub.terminal.components;
+
+import dev.jakub.terminal.Terminal;
+import dev.jakub.terminal.core.TerminalSupport;
+
+import java.io.PrintStream;
+
+/**
+ * System info widget. Use via {@link Terminal#sysinfo()}.
+ * OS, JVM, CPU, RAM from System.getProperty() and Runtime.getRuntime().
+ */
+public final class SysInfo {
+
+    private final TerminalSupport support;
+
+    public SysInfo(TerminalSupport support) {
+        this.support = support;
+    }
+
+    /**
+     * Prints system info as a key-value block to the given stream.
+     */
+    public void print(PrintStream out) {
+        Runtime rt = Runtime.getRuntime();
+        long maxMem = rt.maxMemory() == Long.MAX_VALUE ? rt.totalMemory() : rt.maxMemory();
+        long usedMem = rt.totalMemory() - rt.freeMemory();
+        String os = System.getProperty("os.name", "?") + " " + System.getProperty("os.version", "");
+        String jvm = System.getProperty("java.vm.name", "?") + " " + System.getProperty("java.version", "");
+        int cores = rt.availableProcessors();
+        String ram = formatBytes(usedMem) + " / " + formatBytes(maxMem) + " used";
+
+        KeyValue kv = new KeyValue(support);
+        kv.row("OS", os.trim());
+        kv.row("JVM", jvm.trim());
+        kv.row("CPU", cores + " cores");
+        kv.row("RAM", ram);
+        kv.print(out);
+    }
+
+    private static String formatBytes(long bytes) {
+        if (bytes < 1024) return bytes + " B";
+        if (bytes < 1024 * 1024) return String.format("%.1f KB", bytes / 1024.0);
+        if (bytes < 1024 * 1024 * 1024) return String.format("%.1f MB", bytes / (1024.0 * 1024));
+        return String.format("%.1f GB", bytes / (1024.0 * 1024 * 1024));
+    }
+
+    /**
+     * Prints to stdout.
+     */
+    public void print() {
+        print(System.out);
+    }
+}