feat: add filter rule for chapi config

chapi-application/src/main/kotlin/chapi/app/analyser/config/ChapiConfig.kt

@@ -2,7 +2,8 @@ package chapi.app.analyser.config
 
 data class ChapiConfig(
     var language: String = "",
-    var withoutTest: Boolean = false
+    var withoutTest: Boolean = false,
+    var filterRule: String = ""
 ) {
 
 }

chapi-application/src/main/kotlin/chapi/app/analyser/filter/FileFilter.kt

@@ -5,6 +5,10 @@ import chapi.app.analyser.config.ChapiConfig
 open class FileFilter {
     companion object {
         fun filterByLanguage(path: String, config: ChapiConfig): Boolean {
+            if (config.filterRule.isNotEmpty()) {
+                return config.filterRule.toRegex().matches(path)
+            }
+
             return when (config.language) {
                 "java" -> {
                     path.endsWith(".java")

chapi-application/src/test/kotlin/chapi/app/analyser/filter/FileFilterTest.kt

@@ -0,0 +1,26 @@
+package chapi.app.analyser.filter
+
+import chapi.app.analyser.config.ChapiConfig
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+internal class FileFilterTest {
+    @Test
+    internal fun shouldReturnTrueWhenInputLangJava() {
+        val config = ChapiConfig(
+            language = "java"
+        )
+        val isJavaFile = FileFilter.filterByLanguage("hello.java", config)
+        assertEquals(isJavaFile, true)
+    }
+
+    @Test
+    internal fun shouldEnableRegexToMatchFile() {
+        val config = ChapiConfig(
+            language = "java",
+            filterRule = ".*\\.java"
+        )
+        val isJavaFile = FileFilter.filterByLanguage("hello.java", config)
+        assertEquals(isJavaFile, true)
+    }
+}