Merge pull request #84 from dobesv/list-issingle

mperry · mperry · commit 18ae2515bae3 · 2015-01-16T19:52:52.000+10:00
Merged #84: Add List.isSingle()
diff --git a/core/src/main/java/fj/data/List.java b/core/src/main/java/fj/data/List.java
@@ -1840,4 +1840,11 @@ private void copy() {
     @Override public String toString() {
         return Show.listShow( Show.<A>anyShow() ).show( this ).foldLeft((s, c) -> s + c, "" );
     }
+
+    /**
+     * True if and only if the list has one element. Runs in constant time.
+     */
+    public boolean isSingle() {
+        return isNotEmpty() && tail().isEmpty();
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -1840,4 +1840,11 @@ private void copy() {`
`1840`	`1840`	`@Override public String toString() {`
`1841`	`1841`	`return Show.listShow( Show.<A>anyShow() ).show( this ).foldLeft((s, c) -> s + c, "" );`
`1842`	`1842`	`}`
	`1843`	`+`
	`1844`	`+ /**`
	`1845`	`+ * True if and only if the list has one element. Runs in constant time.`
	`1846`	`+ */`
	`1847`	`+ public boolean isSingle() {`
	`1848`	`+ return isNotEmpty() && tail().isEmpty();`
	`1849`	`+ }`
`1843`	`1850`	`}`