SOLR-921 -- SolrResourceLoader must cache short class name vs fully qualified classname

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@745394 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -179,6 +179,9 @@ Optimizations
  6. SOLR-971: Replace StringBuffer with StringBuilder for instances that do not require thread-safety.
     (Kay Kay via shalin)
 
+ 7. SOLR-921: SolrResourceLoader must cache short class name vs fully qualified classname 
+    (Noble Paul, hossman via shalin)
+
 Bug Fixes
 ----------------------
  1. SOLR-774: Fixed logging level display (Sean Timm via Otis Gospodnetic)

src/java/org/apache/solr/core/SolrResourceLoader.java

@@ -23,11 +23,12 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.io.UnsupportedEncodingException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import java.nio.charset.Charset;
@@ -50,7 +51,6 @@ import org.apache.solr.schema.FieldType;
 import org.apache.solr.update.processor.UpdateRequestProcessorFactory;
 import org.apache.solr.util.plugin.ResourceLoaderAware;
 import org.apache.solr.util.plugin.SolrCoreAware;
-import org.apache.solr.spelling.SpellingQueryConverter;
 
 /**
  * @since solr 1.3
@@ -258,9 +258,37 @@ public class SolrResourceLoader implements ResourceLoader
     return lines;
   }
 
+  /*
+   * A static map of short class name to fully qualified class name 
+   */
+  private static Map<String, String> classNameCache = new ConcurrentHashMap<String, String>();
+
+  /**
+   * This method loads a class either with it's FQN or a short-name (solr.class-simplename or class-simplename).
+   * It tries to load the class with the name that is given first and if it fails, it tries all the known
+   * solr packages. This method caches the FQN of a short-name in a static map in-order to make subsequent lookups
+   * for the same class faster. The caching is done only if the class is loaded by the webapp classloader and it
+   * is loaded using a shortname.
+   *
+   * @param cname The name or the short name of the class.
+   * @param subpackages the packages to be tried if the cnams starts with solr.
+   * @return the loaded class. An exception is thrown if it fails
+   */
   public Class findClass(String cname, String... subpackages) {
-    if (subpackages.length==0) subpackages = packages;
+    if (subpackages.length == 0 || subpackages == packages) {
-  
+      subpackages = packages;
+      String  c = classNameCache.get(cname);
+      if(c != null) {
+        try {
+          return Class.forName(c, true, classLoader);
+        } catch (ClassNotFoundException e) {
+          //this is unlikely
+          log.error("Unable to load cached class-name :  "+ c +" for shortname : "+cname + e);
+        }
+
+      }
+    }
+    Class clazz = null;
     // first try cname == full name
     try {
       return Class.forName(cname, true, classLoader);
@@ -273,13 +301,23 @@ public class SolrResourceLoader implements ResourceLoader
         try {
           String name = base + '.' + subpackage + newName;
           log.trace("Trying class name " + name);
-          return Class.forName(name, true, classLoader);
+          return clazz = Class.forName(name,true,classLoader);
         } catch (ClassNotFoundException e1) {
           // ignore... assume first exception is best.
         }
       }
   
       throw new SolrException( SolrException.ErrorCode.SERVER_ERROR, "Error loading class '" + cname + "'", e, false);
+    }finally{
+      //cache the shortname vs FQN if it is loaded by the webapp classloader  and it is loaded
+      // using a shortname
+      if ( clazz != null &&
+              clazz.getClassLoader() == SolrResourceLoader.class.getClassLoader() &&
+              !cname.equals(clazz.getName()) &&
+              (subpackages.length == 0 || subpackages == packages)) {
+        //store in the cache
+        classNameCache.put(cname, clazz.getName());
+      }
     }
   }