Resolve #46: Updated README with min and max lengths of generated phr…

…ases

README.md

@@ -99,6 +99,8 @@ There is also `PhraseGenerator` provided which generates over 10^9 different phr
     nostalgic_boyd_helps_agitated_noyce
     pensive_allen_tells_fervent_einstein
 
+The generated phrase is 22 to 61 characters long.
+
 ### Listeners
 
 For some use cases, e.g. integration with other frameworks and libraries, it might be useful to register a listener that gets notified every time a trace is either started or stopped.

tracer-core/src/main/java/org/zalando/tracer/PhraseGenerator.java

@@ -460,6 +460,20 @@ static long maxCombinations() {
             .reduce(1, (a, b) -> a * b);
     }
 
+    @VisibleForTesting
+    static int minLength() {
+        return Stream.of(PARTS)
+            .mapToInt(dict -> Stream.of(dict).mapToInt(String::length).min().getAsInt())
+            .sum() + (PARTS.length - 1);
+    }
+
+    @VisibleForTesting
+    static int maxLength() {
+        return Stream.of(PARTS)
+            .mapToInt(dict -> Stream.of(dict).mapToInt(String::length).max().getAsInt())
+            .sum() + (PARTS.length - 1);
+    }
+
     @VisibleForTesting
     static boolean isJacocoHappy() {
         final Holder h = new Holder();

tracer-core/src/test/java/org/zalando/tracer/GeneratorTest.java

@@ -68,4 +68,14 @@ public void testPhraseWozniakIsNotBoring() throws Exception {
     public void testPhraseOver_1_000_000_000() throws Exception {
         assertTrue(PhraseGenerator.maxCombinations() > 1_000_000_000);
     }
+
+    @Test
+    public void testPhraseMinLength() throws Exception {
+        assertThat(PhraseGenerator.minLength(), is(22));
+    }
+
+    @Test
+    public void testPhraseMaxLength() throws Exception {
+        assertThat(PhraseGenerator.maxLength(), is(61));
+    }
 }