From 162b02bf98a19f85dcc592736a8f7863bd6dd148 Mon Sep 17 00:00:00 2001
From: Shekhar Gulati <shekhargulati84@gmail.com>
Date: Sat, 21 May 2016 23:56:51 +0530
Subject: [PATCH] Fixed #28. Added support for `safeTruncate` function

---
 src/main/java/strman/Strman.java     | 31 ++++++++++++++++++++++++++++
 src/test/java/strman/StrmanTest.java | 15 ++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/main/java/strman/Strman.java b/src/main/java/strman/Strman.java
index 9fab5ae..c970560 100644
--- a/src/main/java/strman/Strman.java
+++ b/src/main/java/strman/Strman.java
@@ -812,6 +812,37 @@ public abstract class Strman {
         return value.replaceAll("\\s+$", "");
     }
 
+    /**
+     * Truncate the string securely, not cutting a word in half. It always returns the last full word.
+     *
+     * @param value  The input String
+     * @param length Max size of the truncated String
+     * @param filler String that will be added to the end of the return string. Example: '...'
+     * @return The truncated String
+     */
+    public static String safeTruncate(final String value, final int length, final String filler) {
+        validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
+        if (length == 0) {
+            return "";
+        }
+        if (length >= value.length()) {
+            return value;
+        }
+
+        String[] words = value.split("\\W+");
+        StringJoiner result = new StringJoiner(" ");
+        int spaceCount = 0;
+        for (String word : words) {
+            if (result.length() + word.length() + filler.length() + spaceCount > length) {
+                break;
+            } else {
+                result.add(word);
+                spaceCount++;
+            }
+        }
+        return append(result.toString(), filler);
+    }
+
     public static String decode(final String value, final int digits, final int radix) {
         validate(value, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
         return Arrays
diff --git a/src/test/java/strman/StrmanTest.java b/src/test/java/strman/StrmanTest.java
index c808a7f..d389ee3 100644
--- a/src/test/java/strman/StrmanTest.java
+++ b/src/test/java/strman/StrmanTest.java
@@ -619,4 +619,19 @@ public class StrmanTest {
         assertThat(rightTrim("   strman"), equalTo("   strman"));
         assertThat(rightTrim("strman"), equalTo("strman"));
     }
+
+    @Test
+    public void safeTruncate_shouldSafelyTruncateStrings() throws Exception {
+        assertThat(safeTruncate("foo bar", 0, "."), equalTo(""));
+        assertThat(safeTruncate("foo bar", 4, "."), equalTo("foo."));
+        assertThat(safeTruncate("foo bar", 3, "."), equalTo("."));
+        assertThat(safeTruncate("foo bar", 2, "."), equalTo("."));
+        assertThat(safeTruncate("foo bar", 7, "."), equalTo("foo bar"));
+        assertThat(safeTruncate("foo bar", 8, "."), equalTo("foo bar"));
+        assertThat(safeTruncate("A Javascript string manipulation library.", 16, "..."), equalTo("A Javascript..."));
+        assertThat(safeTruncate("A Javascript string manipulation library.", 15, "..."), equalTo("A Javascript..."));
+        assertThat(safeTruncate("A Javascript string manipulation library.", 14, "..."), equalTo("A..."));
+        assertThat(safeTruncate("A Javascript string manipulation library.", 13, "..."), equalTo("A..."));
+
+    }
 }
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