From 025b3ddb3052c10e886d482b0234c68dec2b1a09 Mon Sep 17 00:00:00 2001
From: Francesca Guiducci <fguiducci@trulia.com>
Date: Sun, 15 Oct 2017 22:09:51 -0700
Subject: [PATCH] Add escapeRegExp function

---
 src/main/java/strman/Strman.java      |  5 +++++
 src/test/java/strman/StrmanTests.java | 26 ++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/src/main/java/strman/Strman.java b/src/main/java/strman/Strman.java
index 6598b0b..bb57787 100644
--- a/src/main/java/strman/Strman.java
+++ b/src/main/java/strman/Strman.java
@@ -1404,6 +1404,11 @@ public static String[] chop(String input, int step) {
                 .toArray(String[]::new);
     }
 
+    public static String escapeRegExp(final String input) {
+        validate(input, NULL_STRING_PREDICATE, NULL_STRING_MSG_SUPPLIER);
+        return input.replaceAll("[\\\\\\^\\$\\*\\+\\-\\?\\.\\|\\(\\)\\{\\}\\[\\]]", "\\\\$0");
+    }
+
     private static void validate(String value, Predicate<String> predicate, final Supplier<String> supplier) {
         if (predicate.test(value)) {
             throw new IllegalArgumentException(supplier.get());
diff --git a/src/test/java/strman/StrmanTests.java b/src/test/java/strman/StrmanTests.java
index ae7b88e..cdf4bd2 100644
--- a/src/test/java/strman/StrmanTests.java
+++ b/src/test/java/strman/StrmanTests.java
@@ -1186,4 +1186,30 @@ public void chop_shouldChopStringByStep() throws Exception {
         assertThat(chop("whitespace", 3).length, equalTo(4));
         assertThat(chop("whitespace", 0)[0].length(), equalTo(10));
     }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void escapeRegExp_shouldThrowException() throws Exception {
+        escapeRegExp(null);
+    }
+
+    @Test
+    public void escapeRegExp_shouldEscapeRegExp() throws Exception {
+        assertThat(escapeRegExp("\\"), equalTo("\\\\"));
+        assertThat(escapeRegExp("^"), equalTo("\\^"));
+        assertThat(escapeRegExp("$"), equalTo("\\$"));
+        assertThat(escapeRegExp("*"), equalTo("\\*"));
+        assertThat(escapeRegExp("+"), equalTo("\\+"));
+        assertThat(escapeRegExp("-"), equalTo("\\-"));
+        assertThat(escapeRegExp("?"), equalTo("\\?"));
+        assertThat(escapeRegExp("."), equalTo("\\."));
+        assertThat(escapeRegExp("|"), equalTo("\\|"));
+        assertThat(escapeRegExp("("), equalTo("\\("));
+        assertThat(escapeRegExp(")"), equalTo("\\)"));
+        assertThat(escapeRegExp("{"), equalTo("\\{"));
+        assertThat(escapeRegExp("}"), equalTo("\\}"));
+        assertThat(escapeRegExp("["), equalTo("\\["));
+        assertThat(escapeRegExp("]"), equalTo("\\]"));
+        assertThat(escapeRegExp("How much is (2+3)? 5"), equalTo("How much is \\(2\\+3\\)\\? 5"));
+        assertThat(escapeRegExp("\\s|_|-|(?<=[a-z])(?=[A-Z])"), equalTo("\\\\s\\|_\\|\\-\\|\\(\\?<=\\[a\\-z\\]\\)\\(\\?=\\[A\\-Z\\]\\)"));
+    }
 }