SOLR-3357: Added expected Class type to ResourceLoader.newInstance

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1326879 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -493,6 +493,9 @@ Other Changes
 * SOLR-3343: Moved FastWriter, FileUtils, RegexFileFilter, RTimer and SystemIdResolver
   from org.apache.solr.common to org.apache.solr.util (Chris Male)
 
+* SOLR-3357: ResourceLoader.newInstance now accepts a Class representation of the expected
+instance type (Chris Male)
+
 Documentation
 ----------------------
 

solr/contrib/clustering/src/java/org/apache/solr/handler/clustering/ClusteringComponent.java

@@ -200,7 +200,7 @@ public class ClusteringComponent extends SearchComponent implements SolrCoreAwar
             className = CarrotClusteringEngine.class.getName();
           }
           SolrResourceLoader loader = core.getResourceLoader();
-          ClusteringEngine clusterer = (ClusteringEngine) loader.newInstance(className);
+          ClusteringEngine clusterer = loader.newInstance(className, ClusteringEngine.class);
           if (clusterer != null) {
             String name = clusterer.init(engineNL, core);
             if (name != null) {

solr/contrib/clustering/src/java/org/apache/solr/handler/clustering/carrot2/CarrotClusteringEngine.java

@@ -283,14 +283,7 @@ public class CarrotClusteringEngine extends SearchClusteringEngine {
 
     // Make sure the requested Carrot2 clustering algorithm class is available
     String carrotAlgorithmClassName = initParams.get(CarrotParams.ALGORITHM);
-    Class<?> algorithmClass = core.getResourceLoader().findClass(carrotAlgorithmClassName);
+    this.clusteringAlgorithmClass = core.getResourceLoader().findClass(carrotAlgorithmClassName, IClusteringAlgorithm.class);
-    if (!IClusteringAlgorithm.class.isAssignableFrom(algorithmClass)) {
-      throw new IllegalArgumentException("Class provided as "
-              + CarrotParams.ALGORITHM + " must implement "
-              + IClusteringAlgorithm.class.getName());
-    }
-    this.clusteringAlgorithmClass = (Class<? extends IClusteringAlgorithm>) algorithmClass;
-
     return result;
   }
 

solr/contrib/dataimporthandler-extras/src/java/org/apache/solr/handler/dataimport/TikaEntityProcessor.java

@@ -121,7 +121,7 @@ public class TikaEntityProcessor extends EntityProcessorBase {
     if(parser.equals(AUTO_PARSER)){
       tikaParser = new AutoDetectParser(tikaConfig);
     } else {
-      tikaParser = (Parser) context.getSolrCore().getResourceLoader().newInstance(parser);
+      tikaParser = context.getSolrCore().getResourceLoader().newInstance(parser, Parser.class);
     }
     try {
       tikaParser.parse(is, contentHandler, metadata , new ParseContext());

solr/contrib/dataimporthandler/src/java/org/apache/solr/handler/dataimport/DocBuilder.java

@@ -863,13 +863,13 @@ public class DocBuilder {
   static Class loadClass(String name, SolrCore core) throws ClassNotFoundException {
     try {
       return core != null ?
-              core.getResourceLoader().findClass(name) :
+              core.getResourceLoader().findClass(name, Object.class) :
               Class.forName(name);
     } catch (Exception e) {
       try {
         String n = DocBuilder.class.getPackage().getName() + "." + name;
         return core != null ?
-                core.getResourceLoader().findClass(n) :
+                core.getResourceLoader().findClass(n, Object.class) :
                 Class.forName(n);
       } catch (Exception e1) {
         throw new ClassNotFoundException("Unable to load " + name + " or " + DocBuilder.class.getPackage().getName() + "." + name, e);

solr/core/src/java/org/apache/solr/analysis/DelimitedPayloadTokenFilterFactory.java

@@ -67,7 +67,7 @@ public class DelimitedPayloadTokenFilterFactory extends BaseTokenFilterFactory i
     } else if (encoderClass.equals("identity")){
       encoder = new IdentityEncoder();
     } else {
-      encoder = (PayloadEncoder) loader.newInstance(encoderClass);
+      encoder = loader.newInstance(encoderClass, PayloadEncoder.class);
     }
 
     String delim = args.get(DELIMITER_ATTR);

solr/core/src/java/org/apache/solr/analysis/FSTSynonymFilterFactory.java

@@ -155,7 +155,7 @@ final class FSTSynonymFilterFactory extends BaseTokenFilterFactory implements Re
   }
   
   private static TokenizerFactory loadTokenizerFactory(ResourceLoader loader, String cname, Map<String,String> args){
-    TokenizerFactory tokFactory = (TokenizerFactory) loader.newInstance(cname);
+    TokenizerFactory tokFactory = loader.newInstance(cname, TokenizerFactory.class);
     tokFactory.init(args);
     if (tokFactory instanceof ResourceLoaderAware) {
       ((ResourceLoaderAware) tokFactory).inform(loader);

solr/core/src/java/org/apache/solr/analysis/SlowSynonymFilterFactory.java

@@ -169,7 +169,7 @@ final class SlowSynonymFilterFactory extends BaseTokenFilterFactory implements R
   }
 
   private static TokenizerFactory loadTokenizerFactory(ResourceLoader loader, String cname, Map<String,String> args){
-    TokenizerFactory tokFactory = (TokenizerFactory)loader.newInstance( cname );
+    TokenizerFactory tokFactory = loader.newInstance(cname, TokenizerFactory.class);
     tokFactory.init( args );
     if (tokFactory instanceof ResourceLoaderAware) {
       ((ResourceLoaderAware) tokFactory).inform(loader);

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

@@ -976,14 +976,7 @@ public class CoreContainer
   protected CoreAdminHandler createMultiCoreHandler(final String adminHandlerClass) {
     // :TODO: why create a new SolrResourceLoader? why not use this.loader ???
     SolrResourceLoader loader = new SolrResourceLoader(solrHome, libLoader, null);
-    Object obj = loader.newAdminHandlerInstance(CoreContainer.this, adminHandlerClass);
+    return loader.newAdminHandlerInstance(CoreContainer.this, adminHandlerClass);
-    if ( !(obj instanceof CoreAdminHandler))
-    {
-      throw new SolrException( SolrException.ErrorCode.SERVER_ERROR,
-          "adminHandlerClass is not of type "+ CoreAdminHandler.class );
-      
-    }
-    return (CoreAdminHandler) obj;
   }
 
   public CoreAdminHandler getMultiCoreHandler() {

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

@@ -331,7 +331,7 @@ public final class SolrCore implements SolrInfoMBean {
     DirectoryFactory dirFactory;
     PluginInfo info = solrConfig.getPluginInfo(DirectoryFactory.class.getName());
     if (info != null) {
-      dirFactory = (DirectoryFactory) getResourceLoader().newInstance(info.className);
+      dirFactory = getResourceLoader().newInstance(info.className, DirectoryFactory.class);
       dirFactory.init(info.initArgs);
     } else {
       dirFactory = new StandardDirectoryFactory();
@@ -344,7 +344,7 @@ public final class SolrCore implements SolrInfoMBean {
     IndexReaderFactory indexReaderFactory;
     PluginInfo info = solrConfig.getPluginInfo(IndexReaderFactory.class.getName());
     if (info != null) {
-      indexReaderFactory = (IndexReaderFactory) resourceLoader.newInstance(info.className);
+      indexReaderFactory = resourceLoader.newInstance(info.className, IndexReaderFactory.class);
       indexReaderFactory.init(info.initArgs);
     } else {
       indexReaderFactory = new StandardIndexReaderFactory();
@@ -407,14 +407,11 @@ public final class SolrCore implements SolrInfoMBean {
    *@return the desired instance
    *@throws SolrException if the object could not be instantiated
    */
-  private <T extends Object> T createInstance(String className, Class<T> cast, String msg) {
+  private <T> T createInstance(String className, Class<T> cast, String msg) {
-    Class clazz = null;
+    Class<? extends T> clazz = null;
     if (msg == null) msg = "SolrCore Object";
     try {
-        clazz = getResourceLoader().findClass(className);
+        clazz = getResourceLoader().findClass(className, cast);
-        if (cast != null && !cast.isAssignableFrom(clazz)) {
-          throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " is not a " +cast.getName());
-        }
       //most of the classes do not have constructors which takes SolrCore argument. It is recommended to obtain SolrCore by implementing SolrCoreAware.
       // So invariably always it will cause a  NoSuchMethodException. So iterate though the list of available constructors
         Constructor[] cons =  clazz.getConstructors();
@@ -424,7 +421,7 @@ public final class SolrCore implements SolrInfoMBean {
             return (T)con.newInstance(this);
           }
         }
-        return (T) getResourceLoader().newInstance(className);//use the empty constructor      
+        return getResourceLoader().newInstance(className, cast);//use the empty constructor
     } catch (SolrException e) {
       throw e;
     } catch (Exception e) {
@@ -432,14 +429,11 @@ public final class SolrCore implements SolrInfoMBean {
     }
   }
   
-  private <T extends Object> T createReloadedUpdateHandler(String className, Class<UpdateHandler> class1, String msg, UpdateHandler updateHandler) {
+  private UpdateHandler createReloadedUpdateHandler(String className, String msg, UpdateHandler updateHandler) {
-    Class clazz = null;
+    Class<? extends UpdateHandler> clazz = null;
     if (msg == null) msg = "SolrCore Object";
     try {
-        clazz = getResourceLoader().findClass(className);
+        clazz = getResourceLoader().findClass(className, UpdateHandler.class);
-        if (class1 != null && !class1.isAssignableFrom(clazz)) {
-          throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " is not a " +class1.getName());
-        }
       //most of the classes do not have constructors which takes SolrCore argument. It is recommended to obtain SolrCore by implementing SolrCoreAware.
       // So invariably always it will cause a  NoSuchMethodException. So iterate though the list of available constructors
         Constructor justSolrCoreCon = null;
@@ -447,14 +441,14 @@ public final class SolrCore implements SolrInfoMBean {
         for (Constructor con : cons) {
           Class[] types = con.getParameterTypes();
           if(types.length == 2 && types[0] == SolrCore.class && types[1] == UpdateHandler.class){
-            return (T)con.newInstance(this, updateHandler);
+            return (UpdateHandler) con.newInstance(this, updateHandler);
           } 
         }
-        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " could not find proper constructor for " +class1.getName());
+        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " could not find proper constructor for " + UpdateHandler.class.getName());
     } catch (SolrException e) {
       throw e;
     } catch (Exception e) {
-      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " failed to instantiate " +class1.getName(), e);
+      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,"Error Instantiating "+msg+", "+className+ " failed to instantiate " + UpdateHandler.class.getName(), e);
     }
   }
 
@@ -482,7 +476,7 @@ public final class SolrCore implements SolrInfoMBean {
   }
   
   private UpdateHandler createUpdateHandler(String className, UpdateHandler updateHandler) {
-    return createReloadedUpdateHandler(className, UpdateHandler.class, "Update Handler", updateHandler);
+    return createReloadedUpdateHandler(className, "Update Handler", updateHandler);
   }
 
   private QueryResponseWriter createQueryResponseWriter(String className) {
@@ -642,7 +636,7 @@ public final class SolrCore implements SolrInfoMBean {
     final PluginInfo info = solrConfig.getPluginInfo(CodecFactory.class.getName());
     final CodecFactory factory;
     if (info != null) {
-      factory = (CodecFactory) schema.getResourceLoader().newInstance(info.className);
+      factory = schema.getResourceLoader().newInstance(info.className, CodecFactory.class);
       factory.init(info.initArgs);
     } else {
       factory = new DefaultCodecFactory();
@@ -925,7 +919,7 @@ public final class SolrCore implements SolrInfoMBean {
   }
   private <T> void addIfNotPresent(Map<String ,T> registry, String name, Class<? extends  T> c){
     if(!registry.containsKey(name)){
-      T searchComp = (T) resourceLoader.newInstance(c.getName());
+      T searchComp = resourceLoader.newInstance(c.getName(), c);
       if (searchComp instanceof NamedListInitializedPlugin){
         ((NamedListInitializedPlugin)searchComp).init( new NamedList() );
       }

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

@@ -30,6 +30,7 @@ import java.net.URLClassLoader;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
+import org.apache.solr.handler.admin.CoreAdminHandler;
 import org.apache.solr.handler.component.ShardHandlerFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -378,13 +379,13 @@ public class SolrResourceLoader implements ResourceLoader
    * @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) {
+  public <T> Class<? extends T> findClass(String cname, Class<T> expectedType, String... subpackages) {
     if (subpackages == null || subpackages.length == 0 || subpackages == packages) {
       subpackages = packages;
       String  c = classNameCache.get(cname);
       if(c != null) {
         try {
-          return Class.forName(c, true, classLoader);
+          return Class.forName(c, true, classLoader).asSubclass(expectedType);
         } catch (ClassNotFoundException e) {
           //this is unlikely
           log.error("Unable to load cached class-name :  "+ c +" for shortname : "+cname + e);
@@ -392,10 +393,10 @@ public class SolrResourceLoader implements ResourceLoader
 
       }
     }
-    Class clazz = null;
+    Class<? extends T> clazz = null;
     // first try cname == full name
     try {
-      return Class.forName(cname, true, classLoader);
+      return Class.forName(cname, true, classLoader).asSubclass(expectedType);
     } catch (ClassNotFoundException e) {
       String newName=cname;
       if (newName.startsWith(project)) {
@@ -405,7 +406,7 @@ public class SolrResourceLoader implements ResourceLoader
         try {
           String name = base + '.' + subpackage + newName;
           log.trace("Trying class name " + name);
-          return clazz = Class.forName(name,true,classLoader);
+          return clazz = Class.forName(name,true,classLoader).asSubclass(expectedType);
         } catch (ClassNotFoundException e1) {
           // ignore... assume first exception is best.
         }
@@ -425,14 +426,14 @@ public class SolrResourceLoader implements ResourceLoader
     }
   }
 
-  public Object newInstance(String cname, String ... subpackages) {
+  public <T> T newInstance(String cname, Class<T> expectedType, String ... subpackages) {
-    Class clazz = findClass(cname,subpackages);
+    Class<? extends T> clazz = findClass(cname, expectedType, subpackages);
     if( clazz == null ) {
       throw new SolrException( SolrException.ErrorCode.SERVER_ERROR,
           "Can not find class: "+cname + " in " + classLoader);
     }
     
-    Object obj = null;
+    T obj = null;
     try {
       obj = clazz.newInstance();
     } 
@@ -458,16 +459,16 @@ public class SolrResourceLoader implements ResourceLoader
     return obj;
   }
 
-  public Object newAdminHandlerInstance(final CoreContainer coreContainer, String cname, String ... subpackages) {
+  public CoreAdminHandler newAdminHandlerInstance(final CoreContainer coreContainer, String cname, String ... subpackages) {
-    Class clazz = findClass(cname,subpackages);
+    Class<? extends CoreAdminHandler> clazz = findClass(cname, CoreAdminHandler.class, subpackages);
     if( clazz == null ) {
       throw new SolrException( SolrException.ErrorCode.SERVER_ERROR,
           "Can not find class: "+cname + " in " + classLoader);
     }
     
-    Object obj = null;
+    CoreAdminHandler obj = null;
     try {
-      Constructor ctor = clazz.getConstructor(CoreContainer.class);
+      Constructor<? extends CoreAdminHandler> ctor = clazz.getConstructor(CoreContainer.class);
       obj = ctor.newInstance(coreContainer);
     } 
     catch (Exception e) {
@@ -489,17 +490,17 @@ public class SolrResourceLoader implements ResourceLoader
 
  
 
-  public Object newInstance(String cName, String [] subPackages, Class[] params, Object[] args){
+  public <T> T newInstance(String cName, Class<T> expectedType, String [] subPackages, Class[] params, Object[] args){
-    Class clazz = findClass(cName,subPackages);
+    Class<? extends T> clazz = findClass(cName, expectedType, subPackages);
     if( clazz == null ) {
       throw new SolrException( SolrException.ErrorCode.SERVER_ERROR,
           "Can not find class: "+cName + " in " + classLoader);
     }
 
-    Object obj = null;
+    T obj = null;
     try {
 
-      Constructor constructor = clazz.getConstructor(params);
+      Constructor<? extends T> constructor = clazz.getConstructor(params);
       obj = constructor.newInstance(args);
     }
     catch (Exception e) {

solr/core/src/java/org/apache/solr/handler/component/SpellCheckComponent.java

@@ -525,7 +525,7 @@ public class SpellCheckComponent extends SearchComponent implements SolrCoreAwar
           if (className == null)
             className = IndexBasedSpellChecker.class.getName();
           SolrResourceLoader loader = core.getResourceLoader();
-          SolrSpellChecker checker = (SolrSpellChecker) loader.newInstance(className);
+          SolrSpellChecker checker = loader.newInstance(className, SolrSpellChecker.class);
           if (checker != null) {
             String dictionary = checker.init(spellchecker, core);
             if (dictionary != null) {

solr/core/src/java/org/apache/solr/schema/CurrencyField.java

@@ -117,14 +117,9 @@ public class CurrencyField extends FieldType implements SchemaAware, ResourceLoa
     args.remove(PARAM_PRECISION_STEP);
 
     try {
-      Class<?> c = schema.getResourceLoader().findClass(exchangeRateProviderClass);
+      Class<? extends ExchangeRateProvider> c = schema.getResourceLoader().findClass(exchangeRateProviderClass, ExchangeRateProvider.class);
-      Object clazz = c.newInstance();
+      provider = c.newInstance();
-      if (clazz instanceof ExchangeRateProvider) {
-        provider = (ExchangeRateProvider) clazz;
       provider.init(args);
-      } else {
-        throw new SolrException(ErrorCode.BAD_REQUEST, "exchangeRateProvider "+exchangeRateProviderClass+" needs to implement ExchangeRateProvider");
-      }
     } catch (Exception e) {
       throw new SolrException(ErrorCode.BAD_REQUEST, "Error instansiating exhange rate provider "+exchangeRateProviderClass+". Please check your FieldType configuration", e);
     }

solr/core/src/java/org/apache/solr/schema/FieldTypePluginLoader.java

@@ -61,7 +61,7 @@ public final class FieldTypePluginLoader
   public FieldTypePluginLoader(final IndexSchema schema,
                                final Map<String, FieldType> fieldTypes,
                                final Collection<SchemaAware> schemaAware) {
-    super("[schema.xml] fieldType", true, true);
+    super("[schema.xml] fieldType", FieldType.class, true, true);
     this.schema = schema;
     this.fieldTypes = fieldTypes;
     this.schemaAware = schemaAware;
@@ -78,7 +78,7 @@ public final class FieldTypePluginLoader
                               String className, 
                               Node node ) throws Exception {
 
-    FieldType ft = (FieldType)loader.newInstance(className);
+    FieldType ft = loader.newInstance(className, FieldType.class);
     ft.setTypeName(name);
     
     String expression = "./analyzer[@type='query']";
@@ -228,8 +228,7 @@ public final class FieldTypePluginLoader
     if (analyzerName != null) {
       try {
         // No need to be core-aware as Analyzers are not in the core-aware list
-        final Class<? extends Analyzer> clazz = loader.findClass
+        final Class<? extends Analyzer> clazz = loader.findClass(analyzerName, Analyzer.class);
-          (analyzerName).asSubclass(Analyzer.class);
         
         try {
           // first try to use a ctor with version parameter 
@@ -265,7 +264,7 @@ public final class FieldTypePluginLoader
       = new ArrayList<CharFilterFactory>();
     AbstractPluginLoader<CharFilterFactory> charFilterLoader =
       new AbstractPluginLoader<CharFilterFactory>
-      ( "[schema.xml] analyzer/charFilter", false, false ) {
+      ("[schema.xml] analyzer/charFilter", CharFilterFactory.class, false, false) {
 
       @Override
       protected void init(CharFilterFactory plugin, Node node) throws Exception {
@@ -298,7 +297,7 @@ public final class FieldTypePluginLoader
       = new ArrayList<TokenizerFactory>(1);
     AbstractPluginLoader<TokenizerFactory> tokenizerLoader =
       new AbstractPluginLoader<TokenizerFactory>
-      ( "[schema.xml] analyzer/tokenizer", false, false ) {
+      ("[schema.xml] analyzer/tokenizer", TokenizerFactory.class, false, false) {
       @Override
       protected void init(TokenizerFactory plugin, Node node) throws Exception {
         if( !tokenizers.isEmpty() ) {
@@ -335,7 +334,7 @@ public final class FieldTypePluginLoader
       = new ArrayList<TokenFilterFactory>();
 
     AbstractPluginLoader<TokenFilterFactory> filterLoader = 
-      new AbstractPluginLoader<TokenFilterFactory>( "[schema.xml] analyzer/filter", false, false )
+      new AbstractPluginLoader<TokenFilterFactory>("[schema.xml] analyzer/filter", TokenFilterFactory.class, false, false)
     {
       @Override
       protected void init(TokenFilterFactory plugin, Node node) throws Exception {

solr/core/src/java/org/apache/solr/schema/IndexSchema.java

@@ -663,7 +663,7 @@ public final class IndexSchema {
       return null;
     } else {
       SimilarityFactory similarityFactory;
-      final Object obj = loader.newInstance(((Element) node).getAttribute("class"), "search.similarities.");
+      final Object obj = loader.newInstance(((Element) node).getAttribute("class"), Object.class, "search.similarities.");
       if (obj instanceof SimilarityFactory) {
         // configure a factory, get a similarity back
         SolrParams params = SolrParams.toSolrParams(DOMUtil.childNodesToNamedList(node));

solr/core/src/java/org/apache/solr/search/CacheConfig.java

@@ -39,7 +39,7 @@ import javax.xml.xpath.XPathConstants;
 public class CacheConfig {
   private String nodeName;
 
-  private Class clazz;
+  private Class<? extends SolrCache> clazz;
   private Map<String,String> args;
   private CacheRegenerator regenerator;
 
@@ -51,7 +51,7 @@ public class CacheConfig {
 
   public CacheConfig() {}
 
-  public CacheConfig(Class clazz, Map<String,String> args, CacheRegenerator regenerator) {
+  public CacheConfig(Class<? extends SolrCache> clazz, Map<String,String> args, CacheRegenerator regenerator) {
     this.clazz = clazz;
     this.args = args;
     this.regenerator = regenerator;
@@ -95,9 +95,9 @@ public class CacheConfig {
     SolrResourceLoader loader = solrConfig.getResourceLoader();
     config.cacheImpl = config.args.get("class");
     config.regenImpl = config.args.get("regenerator");
-    config.clazz = loader.findClass(config.cacheImpl);
+    config.clazz = loader.findClass(config.cacheImpl, SolrCache.class);
     if (config.regenImpl != null) {
-      config.regenerator = (CacheRegenerator) loader.newInstance(config.regenImpl);
+      config.regenerator = loader.newInstance(config.regenImpl, CacheRegenerator.class);
     }
     
     return config;
@@ -105,7 +105,7 @@ public class CacheConfig {
 
   public SolrCache newInstance() {
     try {
-      SolrCache cache = (SolrCache)clazz.newInstance();
+      SolrCache cache = clazz.newInstance();
       persistence[0] = cache.init(args, persistence[0], regenerator);
       return cache;
     } catch (Exception e) {

solr/core/src/java/org/apache/solr/search/ValueSourceParser.java

@@ -344,7 +344,7 @@ public abstract class ValueSourceParser implements NamedListInitializedPlugin {
           }
           dist = new NGramDistance(ngram);
         } else {
-          dist = (StringDistance) fp.req.getCore().getResourceLoader().newInstance(distClass);
+          dist = fp.req.getCore().getResourceLoader().newInstance(distClass, StringDistance.class);
         }
         return new StringDistanceFunction(str1, str2, dist);
       }

solr/core/src/java/org/apache/solr/spelling/AbstractLuceneSpellChecker.java

@@ -109,14 +109,14 @@ public abstract class AbstractLuceneSpellChecker extends SolrSpellChecker {
       } else if (compClass.equalsIgnoreCase(FREQ_COMP)){
         comp = new SuggestWordFrequencyComparator();
       } else{//must be a FQCN
-        comp = (Comparator<SuggestWord>) core.getResourceLoader().newInstance(compClass);
+        comp = (Comparator<SuggestWord>) core.getResourceLoader().newInstance(compClass, Comparator.class);
       }
     } else {
       comp = SuggestWordQueue.DEFAULT_COMPARATOR;
     }
     String strDistanceName = (String)config.get(STRING_DISTANCE);
     if (strDistanceName != null) {
-      sd = (StringDistance) core.getResourceLoader().newInstance(strDistanceName);
+      sd = core.getResourceLoader().newInstance(strDistanceName, StringDistance.class);
       //TODO: Figure out how to configure options.  Where's Spring when you need it?  Or at least BeanUtils...
     } else {
       sd = new LevensteinDistance();

solr/core/src/java/org/apache/solr/spelling/DirectSolrSpellChecker.java

@@ -110,13 +110,13 @@ public class DirectSolrSpellChecker extends SolrSpellChecker {
       else if (compClass.equalsIgnoreCase(FREQ_COMP))
         comp = new SuggestWordFrequencyComparator();
       else //must be a FQCN
-        comp = (Comparator<SuggestWord>) core.getResourceLoader().newInstance(compClass);
+        comp = (Comparator<SuggestWord>) core.getResourceLoader().newInstance(compClass, Comparator.class);
     }
     
     StringDistance sd = DirectSpellChecker.INTERNAL_LEVENSHTEIN;
     String distClass = (String) config.get(STRING_DISTANCE);
     if (distClass != null && !distClass.equalsIgnoreCase(INTERNAL_DISTANCE))
-      sd = (StringDistance) core.getResourceLoader().newInstance(distClass);
+      sd = core.getResourceLoader().newInstance(distClass, StringDistance.class);
 
     float minAccuracy = DEFAULT_ACCURACY;
     Float accuracy = (Float) config.get(ACCURACY);

solr/core/src/java/org/apache/solr/spelling/suggest/Suggester.java

@@ -96,7 +96,7 @@ public class Suggester extends SolrSpellChecker {
       lookupImpl = FSTLookupFactory.class.getName();
     }
 
-    factory = (LookupFactory) core.getResourceLoader().newInstance(lookupImpl);
+    factory = core.getResourceLoader().newInstance(lookupImpl, LookupFactory.class);
     
     lookup = factory.create(config, core);
     String store = (String)config.get(STORE_DIR);

solr/core/src/java/org/apache/solr/update/SolrIndexConfig.java

@@ -180,7 +180,7 @@ public class SolrIndexConfig {
   private MergePolicy buildMergePolicy(IndexSchema schema) {
     String mpClassName = mergePolicyInfo == null ? defaultMergePolicyClassName : mergePolicyInfo.className;
 
-    MergePolicy policy = (MergePolicy) schema.getResourceLoader().newInstance(mpClassName);
+    MergePolicy policy = schema.getResourceLoader().newInstance(mpClassName, MergePolicy.class);
 
     if (policy instanceof LogMergePolicy) {
       LogMergePolicy logMergePolicy = (LogMergePolicy) policy;
@@ -213,7 +213,7 @@ public class SolrIndexConfig {
 
   private MergeScheduler buildMergeScheduler(IndexSchema schema) {
     String msClassName = mergeSchedulerInfo == null ? SolrIndexConfig.DEFAULT_MERGE_SCHEDULER_CLASSNAME : mergeSchedulerInfo.className;
-    MergeScheduler scheduler = (MergeScheduler) schema.getResourceLoader().newInstance(msClassName);
+    MergeScheduler scheduler = schema.getResourceLoader().newInstance(msClassName, MergeScheduler.class);
 
     if (mergeSchedulerInfo != null)
       SolrPluginUtils.invokeSetters(scheduler, mergeSchedulerInfo.initArgs);

solr/core/src/java/org/apache/solr/update/processor/FieldMutatingUpdateProcessor.java

@@ -205,7 +205,7 @@ public abstract class FieldMutatingUpdateProcessor
     
     for (String t : typeClasses) {
       try {
-        classes.add(loader.findClass(t));
+        classes.add(loader.findClass(t, Object.class));
       } catch (Exception e) {
         throw new SolrException(SERVER_ERROR,
                                 "Can't resolve typeClass: " + t, e);

solr/core/src/java/org/apache/solr/update/processor/SignatureUpdateProcessorFactory.java

@@ -142,7 +142,7 @@ public class SignatureUpdateProcessorFactory
           currDocSigFields = sigFields;
         }
 
-        Signature sig = (Signature) req.getCore().getResourceLoader().newInstance(signatureClass); 
+        Signature sig = req.getCore().getResourceLoader().newInstance(signatureClass, Signature.class);
         sig.init(params);
 
         for (String field : currDocSigFields) {

solr/core/src/java/org/apache/solr/util/plugin/AbstractPluginLoader.java

@@ -43,21 +43,23 @@ public abstract class AbstractPluginLoader<T>
   private final String type;
   private final boolean preRegister;
   private final boolean requireName;
+  private final Class<T> pluginClassType;
   
   /**
    * @param type is the 'type' name included in error messages.
    * @param preRegister if true, this will first register all Plugins, then it will initialize them.
    */
-  public AbstractPluginLoader( String type, boolean preRegister, boolean requireName )
+  public AbstractPluginLoader(String type, Class<T> pluginClassType, boolean preRegister, boolean requireName )
   {
     this.type = type;
+    this.pluginClassType = pluginClassType;
     this.preRegister = preRegister;
     this.requireName = requireName;
   }
 
-  public AbstractPluginLoader( String type )
+  public AbstractPluginLoader(String type, Class<T> pluginClassType)
   {
-    this( type, false, true );
+    this(type, pluginClassType, false, true);
   }
   
   /**
@@ -81,7 +83,7 @@ public abstract class AbstractPluginLoader<T>
   @SuppressWarnings("unchecked")
   protected T create( ResourceLoader loader, String name, String className, Node node ) throws Exception
   {
-    return (T) loader.newInstance( className, getDefaultPackages() );
+    return loader.newInstance(className, pluginClassType, getDefaultPackages());
   }
   
   /**

solr/core/src/java/org/apache/solr/util/plugin/MapPluginLoader.java

@@ -31,9 +31,8 @@ public class MapPluginLoader<T extends MapInitializedPlugin> extends AbstractPlu
 {
   private final Map<String,T> registry;
   
-  public MapPluginLoader( String name, Map<String,T> map )
+  public MapPluginLoader(String name, Class<T> pluginClassType, Map<String, T> map) {
-  {
+    super(name, pluginClassType);
-    super( name );
     registry = map;
   }
 

solr/core/src/java/org/apache/solr/util/plugin/NamedListPluginLoader.java

@@ -30,9 +30,8 @@ public class NamedListPluginLoader<T extends NamedListInitializedPlugin> extends
 {
   private final Map<String,T> registry;
   
-  public NamedListPluginLoader( String name, Map<String,T> map )
+  public NamedListPluginLoader(String name, Class<T> pluginClassType, Map<String, T> map) {
-  {
+    super(name, pluginClassType);
-    super( name );
     registry = map;
   }
 

solr/core/src/test/org/apache/solr/analysis/SnowballPorterFilterFactoryTest.java

@@ -69,7 +69,7 @@ public class SnowballPorterFilterFactoryTest extends BaseTokenTestCase {
       return lines;
     }
 
-    public Object newInstance(String cname, String... subpackages) {
+    public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
       return null;
     }
 

solr/core/src/test/org/apache/solr/analysis/TestCollationKeyFilterFactory.java

@@ -166,7 +166,7 @@ public class TestCollationKeyFilterFactory extends BaseTokenTestCase {
       return null;
     }
 
-    public Object newInstance(String cname, String... subpackages) {
+    public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
       return null;
     }
 

solr/core/src/test/org/apache/solr/analysis/TestMultiWordSynonyms.java

@@ -73,7 +73,7 @@ public class TestMultiWordSynonyms extends BaseTokenTestCase {
       return null;
     }
 
-    public Object newInstance(String cname, String... subpackages) {
+    public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
       return null;
     }
 

solr/core/src/test/org/apache/solr/analysis/TestSynonymFilterFactory.java

@@ -108,7 +108,7 @@ public class TestSynonymFilterFactory extends BaseTokenTestCase {
       return Arrays.asList(text.split("\n"));
     }
 
-    public Object newInstance(String cname, String... subpackages) {
+    public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
       return null;
     }
 

solr/core/src/test/org/apache/solr/analysis/TestSynonymMap.java

@@ -282,7 +282,7 @@ public class TestSynonymMap extends LuceneTestCase {
       }
 
       @Override
-      public Object newInstance(String cname, String... subpackages) {
+      public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
         throw new RuntimeException("stub");
       }
 

solr/solrj/src/java/org/apache/solr/common/ResourceLoader.java

@@ -1,4 +1,6 @@
-/**
+package org.apache.solr.common;
+
+/*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -15,8 +17,6 @@
  * limitations under the License.
  */
 
-package org.apache.solr.common;
-
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.List;
@@ -43,5 +43,5 @@ public interface ResourceLoader
    */
   public List<String> getLines(String resource) throws IOException;
   
-  public Object newInstance(String cname, String ... subpackages);
+  public <T> T newInstance(String cname, Class<T> expectedType, String ... subpackages);
 }

solr/test-framework/src/java/org/apache/solr/analysis/StringMockSolrResourceLoader.java

@@ -36,7 +36,7 @@ class StringMockSolrResourceLoader implements ResourceLoader {
     return Arrays.asList(text.split("\n"));
   }
 
-  public Object newInstance(String cname, String... subpackages) {
+  public <T> T newInstance(String cname, Class<T> expectedType, String... subpackages) {
     return null;
   }