From 2b46b11e55712110512ba34f56a7a463aea86d4d Mon Sep 17 00:00:00 2001
From: Almark Ming <glide.ming@gmail.com>
Date: Tue, 17 Dec 2013 16:57:22 +0800
Subject: [PATCH] Update RegexSelector.java Optimize regex format check

Conflicts:
	webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
---
 .../webmagic/selector/RegexSelector.java      |  8 ++++----
 .../webmagic/selector/RegexSelectorTest.java  | 20 +++++++++++--------
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
index 6b1db967b..438189655 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
@@ -26,12 +26,12 @@ public RegexSelector(String regexStr, int group) {
         if (StringUtils.isBlank(regexStr)) {
             throw new IllegalArgumentException("regex must not be empty");
         }
-        if (!StringUtils.contains(regexStr, "(") && !StringUtils.contains(regexStr, ")")) {
+        // Check bracket for regex group. Add default group 1 if there is no group.
+        // Only check if there exists the valid left parenthesis, leave regexp validation for Pattern.
+        if (StringUtils.countMatches(regexStr, "(") - StringUtils.countMatches(regexStr, "\\(") ==
+                StringUtils.countMatches(regexStr, "(?:") - StringUtils.countMatches(regexStr, "\\(?:")) {
             regexStr = "(" + regexStr + ")";
         }
-        if (!StringUtils.contains(regexStr, "(") || !StringUtils.contains(regexStr, ")")) {
-            throw new IllegalArgumentException("regex must have capture group 1");
-        }
         this.regexStr = regexStr;
         try {
             regex = Pattern.compile(regexStr, Pattern.DOTALL | Pattern.CASE_INSENSITIVE);
diff --git a/webmagic-core/src/test/java/us/codecraft/webmagic/selector/RegexSelectorTest.java b/webmagic-core/src/test/java/us/codecraft/webmagic/selector/RegexSelectorTest.java
index 21660a19c..a0b8caff1 100644
--- a/webmagic-core/src/test/java/us/codecraft/webmagic/selector/RegexSelectorTest.java
+++ b/webmagic-core/src/test/java/us/codecraft/webmagic/selector/RegexSelectorTest.java
@@ -1,6 +1,6 @@
 package us.codecraft.webmagic.selector;
 
-import junit.framework.Assert;
+import org.junit.Assert;
 import org.junit.Test;
 
 /**
@@ -8,14 +8,18 @@
  */
 public class RegexSelectorTest {
 
-    @Test
-    public void testInvalidRegex() {
+    @Test(expected = IllegalArgumentException.class)
+    public void testRegexWithSingleLeftBracket() {
         String regex = "\\d+(";
-        try {
-            new RegexSelector(regex);
-            Assert.assertNotNull(regex);
-        } catch (Exception e) {
+        new RegexSelector(regex);
+    }
 
-        }
+    @Test
+    public void testRegexWithLeftBracketQuoted() {
+        String regex = "\\(.+";
+        String source = "(hello world";
+        RegexSelector regexSelector = new RegexSelector(regex);
+        String select = regexSelector.select(source);
+        Assert.assertEquals(source,select);
     }
 }