diff --git a/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/UrlSelector.kt b/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/UrlSelector.kt
index 58068785..70ed67e7 100644
--- a/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/UrlSelector.kt
+++ b/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/UrlSelector.kt
@@ -4,54 +4,46 @@ import com.google.inject.Inject
 import com.google.inject.Singleton
 import com.itangcent.common.model.Request
 import com.itangcent.common.model.URL
-import com.itangcent.common.utils.longest
-import com.itangcent.common.utils.shortest
 import com.itangcent.idea.plugin.api.export.core.ClassExportRuleKeys
 import com.itangcent.idea.plugin.api.export.core.ResolveMultiPath
 import com.itangcent.idea.psi.resource
 import com.itangcent.intellij.config.rule.RuleComputer
 
+/**
+ * The `UrlSelector` class is responsible for selecting a single URL from a given request.
+ * When a request contains a single URL, it is returned as-is. However, when the request contains
+ * multiple URLs, a resolution strategy is determined based on specified rules, and this strategy is
+ * used to resolve the multiple URLs to a single URL.
+ *
+ * The resolution strategy is determined based on [ClassExportRuleKeys.PATH_MULTI], and the default
+ * strategy is [ResolveMultiPath.FIRST].
+ */
 @Singleton
 class UrlSelector {
 
     @Inject
     private val ruleComputer: RuleComputer? = null
 
+    /**
+     * Selects a URL from a given request
+     *
+     * @param request The request containing the path (URL or URLs) to be resolved.
+     * @return The selected URL after applying the resolution strategy.
+     */
     fun selectUrls(request: Request): URL {
         val pathInRequest = request.path ?: return URL.nil()
 
+        // If there's only one URL, return it
         if (pathInRequest.single()) {
             return pathInRequest
         }
 
+        // Determine the resolution strategy based on a rule, defaulting to FIRST if the rule is not set
         val pathMultiResolve = ruleComputer!!.computer(ClassExportRuleKeys.PATH_MULTI, request.resource()!!)?.let {
             ResolveMultiPath.valueOf(it.uppercase())
         } ?: ResolveMultiPath.FIRST
 
-        when (pathMultiResolve) {
-            ResolveMultiPath.ALL -> {
-                return pathInRequest
-            }
-
-            ResolveMultiPath.FIRST -> {
-                return URL.of(pathInRequest.urls().firstOrNull())
-            }
-
-            ResolveMultiPath.LAST -> {
-                return URL.of(pathInRequest.urls().lastOrNull())
-            }
-
-            ResolveMultiPath.LONGEST -> {
-                return URL.of(pathInRequest.urls().longest())
-            }
-
-            ResolveMultiPath.SHORTEST -> {
-                return URL.of(pathInRequest.urls().shortest())
-            }
-
-            else -> {
-                return pathInRequest
-            }
-        }
+        // Resolve and return the URL based on the determined strategy
+        return pathMultiResolve.resolve(pathInRequest)
     }
 }
\ No newline at end of file
diff --git a/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/core/ResolveMultiPath.kt b/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/core/ResolveMultiPath.kt
index c84608a7..5426c86a 100644
--- a/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/core/ResolveMultiPath.kt
+++ b/idea-plugin/src/main/kotlin/com/itangcent/idea/plugin/api/export/core/ResolveMultiPath.kt
@@ -1,9 +1,33 @@
 package com.itangcent.idea.plugin.api.export.core
 
+import com.itangcent.common.model.URL
+import com.itangcent.common.utils.longest
+import com.itangcent.common.utils.shortest
+
+/**
+ * This enumeration defines strategies to resolve multiple URLs to a single URL,
+ * based on different criteria like the first URL, last URL, longest URL, or shortest URL.
+ * It also provides a strategy to return all URLs as-is without any resolution.
+ */
 enum class ResolveMultiPath {
-    FIRST,
-    LAST,
-    LONGEST,
-    SHORTEST,
-    ALL
+    FIRST {
+        override fun resolve(url: URL): URL = URL.of(url.urls().firstOrNull())
+    },
+    LAST {
+        override fun resolve(url: URL): URL = URL.of(url.urls().lastOrNull())
+    },
+    LONGEST {
+        override fun resolve(url: URL): URL = URL.of(url.urls().longest())
+    },
+    SHORTEST {
+        override fun resolve(url: URL): URL = URL.of(url.urls().shortest())
+    },
+    ALL {
+        override fun resolve(url: URL): URL = url
+    };
+
+    /**
+     * resolve the given URL based on the implemented strategy
+     */
+    abstract fun resolve(url: URL): URL
 }
\ No newline at end of file