Jug refactor: Separate information printing logic and its invocation

src/main/java/com/fasterxml/uuid/Jug.java

@@ -20,12 +20,15 @@
 import java.util.*;
 
 import com.fasterxml.uuid.impl.NameBasedGenerator;
+import com.fasterxml.uuid.jug.UsageInfo;
 
 /**
  * Simple command-line interface to UUID generation functionality.
  */
 public class Jug
 {
+    private final UsageInfo usageInfo = new UsageInfo();
+
     protected final static HashMap<String,String> TYPES = new HashMap<String,String>();
     static {
         TYPES.put("time-based", "t");
@@ -46,34 +49,6 @@ public class Jug
         OPTIONS.put("performance", "p");
         OPTIONS.put("verbose", "v");
     }
-
-    protected void printUsage()
-    {
-        String clsName = Jug.class.getName();
-        System.err.println("Usage: java "+clsName+" [options] type");
-        System.err.println("Where options are:");
-        System.err.println("  --count / -c <number>: will generate <number> UUIDs (default: 1)");
-        System.err.println("  --ethernet-address / -e <ether-address>: defines the ethernet address");
-        System.err.println("    (in xx:xx:xx:xx:xx:xx notation, usually obtained using 'ifconfig' etc)");
-        System.err.println("    to use with time-based UUID generation");
-        System.err.println("  --help / -h: lists the usage (ie. what you see now)");
-        System.err.println("  --name / -n: specifies");
-        System.err.println("     o name for name-based UUID generation");
-        System.err.println("     o 'information' part of tag-URI for tag-URI UUID generation");
-        System.err.println("  --namespace / -s: specifies");
-        System.err.println("    o the namespace (DNS or URL) for name-based UUID generation");
-        System.err.println("    o 'authority' part of tag-URI for tag-URI UUID generation;");
-        System.err.println("        (fully-qualified domain name, email address)");
-        System.err.println("  --performance / -p: measure time it takes to generate UUID(s).");
-        System.err.println("    [note that UUIDs are not printed out unless 'verbose' is also specified]");
-        System.err.println("  --verbose / -v: lists additional information about UUID generation\n    (by default only UUIDs are printed out (to make it usable in scripts)");
-        System.err.println("And type is one of:");
-        System.err.println("  time-based / t: generate UUID based on current time and optional\n    location information (defined with -e option)");
-        System.err.println("  random-based / r: generate UUID based on the default secure random number generator");
-        System.err.println("  name-based / n: generate UUID based on MD5 hash of given String ('name')");
-        System.err.println("  reordered-time-based / o: generate UUID based on current time and optional\n    location information (defined with -e option)");
-        System.err.println("  epoch-based / e: generate UUID based on current time (as 'epoch') and random number");
-    }
 
     private void printMap(Map<String,String> m, PrintStream out, boolean option)
     {
@@ -107,7 +82,7 @@ public static void main(String[] args)
 
     public void run(String[] args) {
         if (args.length == 0) {
-            printUsage();
+            usageInfo.print();
             return;
         }
 
@@ -198,7 +173,7 @@ public void run(String[] args) {
                         }
                         break;
                     case 'h':
-                        printUsage();
+                        usageInfo.print();
                         return;
                     case 'n':
                         // Need the name

src/main/java/com/fasterxml/uuid/impl/LoggerFacade.java

@@ -1,10 +1,11 @@
 package com.fasterxml.uuid.impl;
 
+import com.fasterxml.uuid.Jug;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * Wrapper we (only) need to support CLI usage (see {@link com.fasterxml.uuid.Jug}
+ * Wrapper we (only) need to support CLI usage (see {@link Jug}
  * wherein we do not actually  have logger package included; in which case we
  * will print warning(s) out to {@code System.err}.
  * For normal embedded usage no benefits, except if someone forgot their SLF4j API

src/main/java/com/fasterxml/uuid/jug/UsageInfo.java

@@ -0,0 +1,55 @@
+package com.fasterxml.uuid.jug;
+
+import com.fasterxml.uuid.Jug;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+
+public class UsageInfo
+{
+
+    private static final List<String> usageMessages = new ArrayList<>();
+
+    static {
+        usageMessages.add("Usage: java " + Jug.class.getName() + " [options] type");
+        usageMessages.add("Where options are:");
+        usageMessages.add("  --count / -c <number>: will generate <number> UUIDs (default: 1)");
+        usageMessages.add("  --ethernet-address / -e <ether-address>: defines the ethernet address");
+        usageMessages.add("    (in xx:xx:xx:xx:xx:xx notation, usually obtained using 'ifconfig' etc)");
+        usageMessages.add("    to use with time-based UUID generation");
+        usageMessages.add("  --help / -h: lists the usage (ie. what you see now)");
+        usageMessages.add("  --name / -n: specifies");
+        usageMessages.add("     o name for name-based UUID generation");
+        usageMessages.add("     o 'information' part of tag-URI for tag-URI UUID generation");
+        usageMessages.add("  --namespace / -s: specifies");
+        usageMessages.add("    o the namespace (DNS or URL) for name-based UUID generation");
+        usageMessages.add("    o 'authority' part of tag-URI for tag-URI UUID generation;");
+        usageMessages.add("        (fully-qualified domain name, email address)");
+        usageMessages.add("  --performance / -p: measure time it takes to generate UUID(s).");
+        usageMessages.add("    [note that UUIDs are not printed out unless 'verbose' is also specified]");
+        usageMessages.add("  --verbose / -v: lists additional information about UUID generation\n    (by default only UUIDs are printed out (to make it usable in scripts)");
+        usageMessages.add("And type is one of:");
+        usageMessages.add("  time-based / t: generate UUID based on current time and optional\n    location information (defined with -e option)");
+        usageMessages.add("  random-based / r: generate UUID based on the default secure random number generator");
+        usageMessages.add("  name-based / n: generate UUID based on MD5 hash of given String ('name')");
+        usageMessages.add("  reordered-time-based / o: generate UUID based on current time and optional\n    location information (defined with -e option)");
+        usageMessages.add("  epoch-based / e: generate UUID based on current time (as 'epoch') and random number");
+    }
+
+    /**
+     * Uses default print mechanism
+     */
+    public void print() {
+        print(System.err::println);
+    }
+
+    /**
+     * Uses specific print mechanism
+     *
+     * @param printer specific printer for messages
+     */
+    public void print(Consumer<String> printer) {
+        usageMessages.forEach(printer);
+    }
+}

src/test/java/com/fasterxml/uuid/JugNamedTest.java → src/test/java/com/fasterxml/uuid/jug/JugNamedTest.java

@@ -1,5 +1,6 @@
-package com.fasterxml.uuid;
+package com.fasterxml.uuid.jug;
 
+import com.fasterxml.uuid.Jug;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -175,4 +176,4 @@ public String toString() {
             }
         }
     }
-}
+}

src/test/java/com/fasterxml/uuid/JugNoArgsTest.java → src/test/java/com/fasterxml/uuid/jug/JugNoArgsTest.java

@@ -1,5 +1,6 @@
-package com.fasterxml.uuid;
+package com.fasterxml.uuid.jug;
 
+import com.fasterxml.uuid.Jug;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -214,4 +215,4 @@ public static List<String> useCases() {
                 "m"
                 );
     }
-}
+}

src/test/java/com/fasterxml/uuid/jug/UsageInfoTest.java

@@ -0,0 +1,73 @@
+package com.fasterxml.uuid.jug;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+import static org.junit.Assert.assertEquals;
+
+public class UsageInfoTest {
+
+    private final ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    private final ByteArrayOutputStream errContent = new ByteArrayOutputStream();
+
+    private final String expectedMessage = "Usage: java com.fasterxml.uuid.Jug [options] type\n" +
+            "Where options are:\n" +
+            "  --count / -c <number>: will generate <number> UUIDs (default: 1)\n" +
+            "  --ethernet-address / -e <ether-address>: defines the ethernet address\n" +
+            "    (in xx:xx:xx:xx:xx:xx notation, usually obtained using 'ifconfig' etc)\n" +
+            "    to use with time-based UUID generation\n" +
+            "  --help / -h: lists the usage (ie. what you see now)\n" +
+            "  --name / -n: specifies\n" +
+            "     o name for name-based UUID generation\n" +
+            "     o 'information' part of tag-URI for tag-URI UUID generation\n" +
+            "  --namespace / -s: specifies\n" +
+            "    o the namespace (DNS or URL) for name-based UUID generation\n" +
+            "    o 'authority' part of tag-URI for tag-URI UUID generation;\n" +
+            "        (fully-qualified domain name, email address)\n" +
+            "  --performance / -p: measure time it takes to generate UUID(s).\n" +
+            "    [note that UUIDs are not printed out unless 'verbose' is also specified]\n" +
+            "  --verbose / -v: lists additional information about UUID generation\n" +
+            "    (by default only UUIDs are printed out (to make it usable in scripts)\n" +
+            "And type is one of:\n" +
+            "  time-based / t: generate UUID based on current time and optional\n" +
+            "    location information (defined with -e option)\n" +
+            "  random-based / r: generate UUID based on the default secure random number generator\n" +
+            "  name-based / n: generate UUID based on MD5 hash of given String ('name')\n" +
+            "  reordered-time-based / o: generate UUID based on current time and optional\n" +
+            "    location information (defined with -e option)\n" +
+            "  epoch-based / e: generate UUID based on current time (as 'epoch') and random number" +
+            "\n";
+
+    @Before
+    public void setup() {
+        PrintStream stubbedStream = new PrintStream(outContent);
+        System.setOut(stubbedStream);
+
+        PrintStream stubbedErrStream = new PrintStream(errContent);
+        System.setErr(stubbedErrStream);
+    }
+
+    /**
+     * This test contains trailed '\n' symbol.
+     */
+    @Test
+    public void validateMessage_defaultStdError() {
+        new UsageInfo().print();
+
+        String actual = errContent.toString();
+
+        assertEquals(expectedMessage, actual);
+    }
+
+    @Test
+    public void validateMessage_defaultStdOut() {
+        new UsageInfo().print(System.out::println);
+
+        String actual = outContent.toString();
+
+        assertEquals(expectedMessage, actual);
+    }
+}