SOLR-14125 : Streaming expressions to be loadable from packages (#1108)

SOLR-14125: Make <expressible> plugins work with packages

lucene/analysis/kuromoji/src/java/org/apache/lucene/analysis/ja/dict/UserDictionary.java

@@ -29,8 +29,8 @@ import java.util.TreeMap;
 
 import org.apache.lucene.analysis.ja.util.CSVUtil;
 import org.apache.lucene.util.IntsRefBuilder;
-import org.apache.lucene.util.fst.FSTCompiler;
 import org.apache.lucene.util.fst.FST;
+import org.apache.lucene.util.fst.FSTCompiler;
 import org.apache.lucene.util.fst.PositiveIntOutputs;
 
 /**

solr/CHANGES.txt

@@ -161,6 +161,8 @@ Improvements
 
 * SOLR-14095: Replace Java serialization with Javabin in the Overseer queues (Tomás Fernández Löbbe)
 
+* SOLR-14125: Make <expressible> plugins work with packages (noble)
+
 Optimizations
 ---------------------
 (No changes)

solr/core/src/java/org/apache/solr/handler/GraphHandler.java

@@ -19,6 +19,7 @@ package org.apache.solr.handler;
 
 import java.io.IOException;
 import java.lang.invoke.MethodHandles;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -27,7 +28,9 @@ import java.util.Map.Entry;
 import org.apache.solr.client.solrj.io.Tuple;
 import org.apache.solr.client.solrj.io.comp.StreamComparator;
 import org.apache.solr.client.solrj.io.graph.Traversal;
-import org.apache.solr.client.solrj.io.stream.*;
+import org.apache.solr.client.solrj.io.stream.ExceptionStream;
+import org.apache.solr.client.solrj.io.stream.StreamContext;
+import org.apache.solr.client.solrj.io.stream.TupleStream;
 import org.apache.solr.client.solrj.io.stream.expr.DefaultStreamFactory;
 import org.apache.solr.client.solrj.io.stream.expr.Explanation;
 import org.apache.solr.client.solrj.io.stream.expr.Expressible;
@@ -38,6 +41,8 @@ import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.common.params.SolrParams;
 import org.apache.solr.common.util.NamedList;
 import org.apache.solr.core.CoreContainer;
+import org.apache.solr.core.PluginInfo;
+import org.apache.solr.core.SolrConfig;
 import org.apache.solr.core.SolrCore;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.response.SolrQueryResponse;
@@ -90,11 +95,21 @@ public class GraphHandler extends RequestHandlerBase implements SolrCoreAware, P
     Object functionMappingsObj = initArgs.get("streamFunctions");
     if(null != functionMappingsObj){
       NamedList<?> functionMappings = (NamedList<?>)functionMappingsObj;
-      for(Entry<String,?> functionMapping : functionMappings){
+      for(Entry<String,?> functionMapping : functionMappings) {
-        Class<? extends Expressible> clazz = core.getResourceLoader().findClass((String)functionMapping.getValue(),
+        String key = functionMapping.getKey();
-            Expressible.class);
+        PluginInfo pluginInfo = new PluginInfo(key, Collections.singletonMap("class", functionMapping.getValue()));
-        streamFactory.withFunctionName(functionMapping.getKey(), clazz);
+
+        if (pluginInfo.pkgName == null) {
+          Class<? extends Expressible> clazz = core.getResourceLoader().findClass((String) functionMapping.getValue(),
+              Expressible.class);
+          streamFactory.withFunctionName(key, clazz);
+        } else {
+          StreamHandler.ExpressibleHolder holder = new StreamHandler.ExpressibleHolder(pluginInfo, core, SolrConfig.classVsSolrPluginInfo.get(Expressible.class));
+          streamFactory.withFunctionName(key, () -> holder.getClazz());
+        }
+
       }
+
     }
   }
 

solr/core/src/java/org/apache/solr/handler/SolrConfigHandler.java

@@ -45,6 +45,7 @@ import org.apache.solr.client.solrj.SolrClient;
 import org.apache.solr.client.solrj.SolrRequest;
 import org.apache.solr.client.solrj.SolrResponse;
 import org.apache.solr.client.solrj.impl.HttpSolrClient;
+import org.apache.solr.client.solrj.io.stream.expr.Expressible;
 import org.apache.solr.cloud.ZkController;
 import org.apache.solr.cloud.ZkSolrResourceLoader;
 import org.apache.solr.common.SolrException;
@@ -588,9 +589,17 @@ public class SolrConfigHandler extends RequestHandlerBase implements SolrCoreAwa
     private boolean verifyClass(CommandOperation op, String clz, Class expected) {
       if (clz == null) return true;
       if (!"true".equals(String.valueOf(op.getStr("runtimeLib", null)))) {
+        PluginInfo info = new PluginInfo(SolrRequestHandler.TYPE, op.getDataMap());
         //this is not dynamically loaded so we can verify the class right away
         try {
-          req.getCore().createInitInstance(new PluginInfo(SolrRequestHandler.TYPE, op.getDataMap()), expected, clz, "");
+          if(expected == Expressible.class) {
+            SolrResourceLoader resourceLoader = info.pkgName == null ?
+                req.getCore().getResourceLoader() :
+                req.getCore().getResourceLoader(info.pkgName);
+            resourceLoader.findClass(info.className, expected);
+          } else {
+            req.getCore().createInitInstance(info, expected, clz, "");
+          }
         } catch (Exception e) {
           log.error("Error checking plugin : ", e);
           op.addError(e.getMessage());

solr/core/src/java/org/apache/solr/handler/StreamHandler.java

@@ -33,7 +33,10 @@ import org.apache.solr.client.solrj.io.ModelCache;
 import org.apache.solr.client.solrj.io.SolrClientCache;
 import org.apache.solr.client.solrj.io.Tuple;
 import org.apache.solr.client.solrj.io.comp.StreamComparator;
-import org.apache.solr.client.solrj.io.stream.*;
+import org.apache.solr.client.solrj.io.stream.DaemonStream;
+import org.apache.solr.client.solrj.io.stream.ExceptionStream;
+import org.apache.solr.client.solrj.io.stream.StreamContext;
+import org.apache.solr.client.solrj.io.stream.TupleStream;
 import org.apache.solr.client.solrj.io.stream.expr.Explanation;
 import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType;
 import org.apache.solr.client.solrj.io.stream.expr.Expressible;
@@ -44,6 +47,7 @@ import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParser;
 import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
 import org.apache.solr.client.solrj.routing.RequestReplicaListTransformerGenerator;
 import org.apache.solr.cloud.ZkController;
+import org.apache.solr.common.MapWriter;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.cloud.ZkStateReader;
 import org.apache.solr.common.params.CommonParams;
@@ -52,7 +56,10 @@ import org.apache.solr.common.params.SolrParams;
 import org.apache.solr.core.CloseHook;
 import org.apache.solr.core.CoreContainer;
 import org.apache.solr.core.PluginInfo;
+import org.apache.solr.core.SolrConfig;
 import org.apache.solr.core.SolrCore;
+import org.apache.solr.pkg.PackageLoader;
+import org.apache.solr.pkg.PackagePluginHolder;
 import org.apache.solr.request.SolrQueryRequest;
 import org.apache.solr.response.SolrQueryResponse;
 import org.apache.solr.security.AuthorizationContext;
@@ -87,7 +94,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
   private SolrDefaultStreamFactory streamFactory = new SolrDefaultStreamFactory();
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
   private String coreName;
-  private Map<String,DaemonStream> daemons = Collections.synchronizedMap(new HashMap());
+  private Map<String, DaemonStream> daemons = Collections.synchronizedMap(new HashMap());
 
   @Override
   public PermissionNameProvider.Name getPermissionName(AuthorizationContext request) {
@@ -118,8 +125,14 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
     // This pulls all the overrides and additions from the config
     List<PluginInfo> pluginInfos = core.getSolrConfig().getPluginInfos(Expressible.class.getName());
     for (PluginInfo pluginInfo : pluginInfos) {
-      Class<? extends Expressible> clazz = core.getMemClassLoader().findClass(pluginInfo.className, Expressible.class);
+      if (pluginInfo.pkgName != null) {
-      streamFactory.withFunctionName(pluginInfo.name, clazz);
+        ExpressibleHolder holder = new ExpressibleHolder(pluginInfo, core, SolrConfig.classVsSolrPluginInfo.get(Expressible.class));
+        streamFactory.withFunctionName(pluginInfo.name,
+            () -> holder.getClazz());
+      } else {
+        Class<? extends Expressible> clazz = core.getMemClassLoader().findClass(pluginInfo.className, Expressible.class);
+        streamFactory.withFunctionName(pluginInfo.name, clazz);
+      }
     }
 
     core.addCloseHook(new CloseHook() {
@@ -135,6 +148,24 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
     });
   }
 
+  public static class ExpressibleHolder extends PackagePluginHolder {
+    private Class clazz;
+
+    public ExpressibleHolder(PluginInfo info, SolrCore core, SolrConfig.SolrPluginInfo pluginMeta) {
+      super(info, core, pluginMeta);
+    }
+
+    public Class getClazz() {
+      return clazz;
+    }
+
+    @Override
+    protected void initNewInstance(PackageLoader.Package.Version newest) {
+      clazz = newest.getLoader().findClass(pluginInfo.className, Expressible.class);
+    }
+
+  }
+
   public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse rsp) throws Exception {
     SolrParams params = req.getParams();
     params = adjustParams(params);
@@ -220,6 +251,10 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
 
   private void handleAdmin(SolrQueryRequest req, SolrQueryResponse rsp, SolrParams params) {
     String action = params.get("action").toLowerCase(Locale.ROOT).trim();
+    if ("plugins".equals(action)) {
+      rsp.add("plugins", (MapWriter) ew -> streamFactory.getFunctionNames().forEach((s, classSupplier) -> ew.putNoEx(s, classSupplier.get().getName())));
+      return;
+    }
 
     if ("list".equals(action)) {
       Collection<DaemonStream> vals = daemons.values();
@@ -255,10 +290,10 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
         rsp.add("result-set", new DaemonResponseStream("Deamon:" + id + " killed on " + coreName));
         break;
 
-       default:
+      default:
-         rsp.add("result-set", new DaemonResponseStream("Deamon:" + id + " action '"
+        rsp.add("result-set", new DaemonResponseStream("Deamon:" + id + " action '"
-             + action + "' not recognized on " + coreName));
+            + action + "' not recognized on " + coreName));
-         break;
+        break;
     }
   }
 
@@ -288,11 +323,14 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       return null;
     }
 
-    public void close() {}
+    public void close() {
+    }
 
-    public void open() {}
+    public void open() {
+    }
 
-    public void setStreamContext(StreamContext context) {}
+    public void setStreamContext(StreamContext context) {
+    }
 
     public List<TupleStream> children() {
       return null;
@@ -335,11 +373,14 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       return null;
     }
 
-    public void close() {}
+    public void close() {
+    }
 
-    public void open() {}
+    public void open() {
+    }
 
-    public void setStreamContext(StreamContext context) {}
+    public void setStreamContext(StreamContext context) {
+    }
 
     public List<TupleStream> children() {
       return null;
@@ -378,11 +419,14 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
       return null;
     }
 
-    public void close() {}
+    public void close() {
+    }
 
-    public void open() {}
+    public void open() {
+    }
 
-    public void setStreamContext(StreamContext context) {}
+    public void setStreamContext(StreamContext context) {
+    }
 
     public List<TupleStream> children() {
       return null;
@@ -462,9 +506,9 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
     }
   }
 
-  private Map<String,List<String>> getCollectionShards(SolrParams params) {
+  private Map<String, List<String>> getCollectionShards(SolrParams params) {
 
-    Map<String,List<String>> collectionShards = new HashMap();
+    Map<String, List<String>> collectionShards = new HashMap();
     Iterator<String> paramsIt = params.getParameterNamesIterator();
     while (paramsIt.hasNext()) {
       String param = paramsIt.next();

solr/core/src/java/org/apache/solr/pkg/PackagePluginHolder.java

@@ -104,12 +104,17 @@ public class PackagePluginHolder<T> extends PluginBag.PluginHolder<T> {
     log.info("loading plugin: {} -> {} using  package {}:{}",
         pluginInfo.type, pluginInfo.name, pkg.name(), newest.getVersion());
 
+    initNewInstance(newest);
+    pkgVersion = newest;
+
+  }
+
+  protected void initNewInstance(PackageLoader.Package.Version newest) {
     Object instance = SolrCore.createInstance(pluginInfo.className,
         pluginMeta.clazz, pluginMeta.getCleanTag(), core, newest.getLoader());
     PluginBag.initInstance(instance, pluginInfo);
     T old = inst;
     inst = (T) instance;
-    pkgVersion = newest;
     if (old instanceof AutoCloseable) {
       AutoCloseable closeable = (AutoCloseable) old;
       try {

solr/core/src/test-files/runtimecode/sig.txt

@@ -65,6 +65,10 @@ openssl dgst -sha1 -sign ../cryptokeys/priv_key512.pem testurp_v2.jar.bin | open
 
 P/ptFXRvQMd4oKPvadSpd+A9ffwY3gcex5GVFVRy3df0/OF8XT5my8rQz7FZva+2ORbWxdXS8NKwNrbPVHLGXw==
 
+openssl dgst -sha1 -sign ../cryptokeys/priv_key512.pem expressible.jar.bin | openssl enc -base64 | openssl enc -base64 | tr -d \\n | sed
+
+ZOT11arAiPmPZYOHzqodiNnxO9pRyRozWZEBX8XGjU1/HJptFnZK+DI7eXnUtbNaMcbXE2Ze8hh4M/eGyhY8BQ==
+
 ====================sha512====================
 
 openssl dgst -sha512 runtimelibs.jar.bin
@@ -95,6 +99,11 @@ openssl dgst -sha512 testurp_v1.jar.bin
 openssl dgst -sha512 testurp_v2.jar.bin
 
 5c4c0c454a032916e48a1c14a0fecbd6658658a66aedec5168b7222f2e3c0c63fbe09637238a9325ce2e95a2c8521834397a97701ead46c681aa20c9fccb6654
+
+openssl dgst -sha512 expressible.jar.bin
+
+3474a1414c8329c71ef5db2d3eb6e870363bdd7224a836aab561dccf5e8bcee4974ac799e72398c7e0b0c01972bab1c7454c8a4e791a8865bb676c0440627388
+
 =============sha256============================
 
 openssl dgst -sha256 runtimelibs.jar.bin

solr/core/src/test/org/apache/solr/pkg/TestPackages.java

@@ -92,6 +92,7 @@ public class TestPackages extends SolrCloudTestCase {
       String FILE3 = "/mypkg/runtimelibs_v3.jar";
       String URP1 = "/mypkg/testurpv1.jar";
       String URP2 = "/mypkg/testurpv2.jar";
+      String EXPR1 = "/mypkg/expressible.jar";
       String COLLECTION_NAME = "testPluginLoadingColl";
       byte[] derFile = readFile("cryptokeys/pub_key512.der");
       cluster.getZkClient().makePath("/keys/exe", true);
@@ -102,10 +103,13 @@ public class TestPackages extends SolrCloudTestCase {
       postFileAndWait(cluster, "runtimecode/testurp_v1.jar.bin", URP1,
           "h6UmMzuPqu4hQFGLBMJh/6kDSEXpJlgLsQDXx0KuxXWkV5giilRP57K3towiJRh2J+rqihqIghNCi3YgzgUnWQ==");
 
+      postFileAndWait(cluster, "runtimecode/expressible.jar.bin", EXPR1,
+          "ZOT11arAiPmPZYOHzqodiNnxO9pRyRozWZEBX8XGjU1/HJptFnZK+DI7eXnUtbNaMcbXE2Ze8hh4M/eGyhY8BQ==");
+
       Package.AddVersion add = new Package.AddVersion();
       add.version = "1.0";
       add.pkg = "mypkg";
-      add.files = Arrays.asList(new String[]{FILE1, URP1});
+      add.files = Arrays.asList(new String[]{FILE1, URP1, EXPR1});
       V2Request req = new V2Request.Builder("/cluster/package")
           .forceV2(true)
           .withMethod(SolrRequest.METHOD.POST)
@@ -134,7 +138,8 @@ public class TestPackages extends SolrCloudTestCase {
           "'create-requesthandler' : { 'name' : '/runtime', 'class': 'mypkg:org.apache.solr.core.RuntimeLibReqHandler' }," +
           "'create-searchcomponent' : { 'name' : 'get', 'class': 'mypkg:org.apache.solr.core.RuntimeLibSearchComponent'  }," +
           "'create-queryResponseWriter' : { 'name' : 'json1', 'class': 'mypkg:org.apache.solr.core.RuntimeLibResponseWriter' }" +
-          "'create-updateProcessor' : { 'name' : 'myurp', 'class': 'mypkg:org.apache.solr.update.TestVersionedURP' }" +
+          "'create-updateProcessor' : { 'name' : 'myurp', 'class': 'mypkg:org.apache.solr.update.TestVersionedURP' }," +
+          " create-expressible: {name: mincopy , class: 'mypkg:org.apache.solr.client.solrj.io.stream.metrics.MinCopyMetric'}" +
           "}";
       cluster.getSolrClient().request(new ConfigRequest(payload) {
         @Override
@@ -159,6 +164,20 @@ public class TestPackages extends SolrCloudTestCase {
           COLLECTION_NAME, "updateProcessor", "myurp",
           "mypkg", "1.0" );
 
+      verifyCmponent(cluster.getSolrClient(),
+          COLLECTION_NAME, "expressible", "mincopy",
+          "mypkg", "1.0" );
+
+      TestDistribPackageStore.assertResponseValues(10,
+          cluster.getSolrClient() ,
+          new GenericSolrRequest(SolrRequest.METHOD.GET,
+              "/stream", new MapSolrParams((Map) Utils.makeMap("collection", COLLECTION_NAME,
+                  WT, JAVABIN,
+                  "action", "plugins"
+                  ))), Utils.makeMap(
+              ":plugins:mincopy", "org.apache.solr.client.solrj.io.stream.metrics.MinCopyMetric"
+          ));
+
       UpdateRequest ur = new UpdateRequest();
       ur.add(new SolrInputDocument("id", "1"));
       ur.setParam("processor", "myurp");
@@ -192,7 +211,7 @@ public class TestPackages extends SolrCloudTestCase {
           "P/ptFXRvQMd4oKPvadSpd+A9ffwY3gcex5GVFVRy3df0/OF8XT5my8rQz7FZva+2ORbWxdXS8NKwNrbPVHLGXw==");
       //add the version using package API
       add.version = "1.1";
-      add.files = Arrays.asList(new String[]{FILE2,URP2});
+      add.files = Arrays.asList(new String[]{FILE2,URP2, EXPR1});
       req.process(cluster.getSolrClient());
 
       verifyCmponent(cluster.getSolrClient(),
@@ -222,7 +241,7 @@ public class TestPackages extends SolrCloudTestCase {
           "a400n4T7FT+2gM0SC6+MfSOExjud8MkhTSFylhvwNjtWwUgKdPFn434Wv7Qc4QEqDVLhQoL3WqYtQmLPti0G4Q==");
 
       add.version = "2.1";
-      add.files = Arrays.asList(new String[]{FILE3, URP2});
+      add.files = Arrays.asList(new String[]{FILE3, URP2, EXPR1});
       req.process(cluster.getSolrClient());
 
       //now let's verify that the classes are updated
@@ -304,7 +323,7 @@ public class TestPackages extends SolrCloudTestCase {
       }.process(cluster.getSolrClient()) ;
 
       add.version = "2.1";
-      add.files = Arrays.asList(new String[]{FILE3, URP2});
+      add.files = Arrays.asList(new String[]{FILE3, URP2, EXPR1});
       req.process(cluster.getSolrClient());
 
       //the collections mypkg is set to use version 1.1
@@ -368,6 +387,21 @@ public class TestPackages extends SolrCloudTestCase {
     }
 
   }
+   /* new V2Request.Builder("/c/"+COLLECTIONORALIAS+"/config").withMethod(SolrRequest.METHOD.POST)
+        .withPayload("{add-expressible: {name: mincopy , class: org.apache.solr.client.solrj.io.stream.metrics.MinCopyMetric}}")
+    .build().process(cluster.getSolrClient());
+
+  ModifiableSolrParams _params = new ModifiableSolrParams();
+  QueryRequest query = new QueryRequest(new MapSolrParams("action","plugins", "collection", COLLECTIONORALIAS, "wt", "javabin"));
+    query.setPath("/stream");
+  NamedList<Object> rsp = cluster.getSolrClient().request(query);
+  assertEquals("org.apache.solr.client.solrj.io.stream.metrics.MinCopyMetric", rsp._getStr("/plugins/mincopy", null));
+  _params = new ModifiableSolrParams();
+  query = new QueryRequest(new MapSolrParams("componentName","mincopy", "meta" ,"true", "collection", COLLECTIONORALIAS, "wt", "javabin"));
+    query.setPath("/config/expressible");
+  rsp = cluster.getSolrClient().request(query);
+
+    System.out.println();*/
 
   private void executeReq(String uri, JettySolrRunner jetty, Utils.InputStreamConsumer parser, Map expected) throws Exception {
     try(HttpSolrClient client = (HttpSolrClient) jetty.newClient()){
@@ -390,7 +424,6 @@ public class TestPackages extends SolrCloudTestCase {
         "componentName", componentName,
         "meta", "true"));
 
-    String s = "queryResponseWriter";
     GenericSolrRequest req1 = new GenericSolrRequest(SolrRequest.METHOD.GET,
         "/config/" + componentType, params);
     TestDistribPackageStore.assertResponseValues(10,

solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/expr/StreamFactory.java

@@ -21,11 +21,13 @@ import java.io.Serializable;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import org.apache.solr.client.solrj.io.comp.ComparatorOrder;
@@ -44,7 +46,7 @@ import org.apache.solr.client.solrj.io.stream.metrics.Metric;
 public class StreamFactory implements Serializable {
   
   private transient HashMap<String,String> collectionZkHosts;
-  private transient HashMap<String,Class<? extends Expressible>> functionNames;
+  private transient HashMap<String,Supplier<Class<? extends Expressible>>> functionNames;
   private transient String defaultZkHost;
   private transient String defaultCollection;
   
@@ -79,14 +81,20 @@ public class StreamFactory implements Serializable {
     return null;
   }
   
-  public Map<String,Class<? extends Expressible>> getFunctionNames(){
+  public Map<String, Supplier<Class<? extends Expressible>>> getFunctionNames() {
-    return functionNames;
+    return Collections.unmodifiableMap(functionNames);
   }
   public StreamFactory withFunctionName(String functionName, Class<? extends Expressible> clazz){
+    this.functionNames.put(functionName, () -> clazz);
+    return this;
+  }
+
+   public StreamFactory withFunctionName(String functionName, Supplier< Class<? extends Expressible>> clazz){
     this.functionNames.put(functionName, clazz);
     return this;
   }
-  
+
+
   public StreamExpressionParameter getOperand(StreamExpression expression, int parameterIndex){
     if(null == expression.getParameters() || parameterIndex >= expression.getParameters().size()){
       return null;
@@ -173,14 +181,15 @@ public class StreamFactory implements Serializable {
     List<StreamExpression> allStreamExpressions = getExpressionOperands(expression);
     
     parameterLoop:
-    for(StreamExpression streamExpression : allStreamExpressions){
+    for(StreamExpression streamExpression : allStreamExpressions) {
-      if(functionNames.containsKey(streamExpression.getFunctionName())){
+      Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(streamExpression.getFunctionName());
-        for(Class clazz : clazzes){
+      if (classSupplier != null) {
-          if(!clazz.isAssignableFrom(functionNames.get(streamExpression.getFunctionName()))){
+        for (Class clazz : clazzes) {
+          if (!clazz.isAssignableFrom(classSupplier.get())) {
             continue parameterLoop;
           }
         }
-        
+
         matchingStreamExpressions.add(streamExpression);
       }
     }
@@ -189,9 +198,10 @@ public class StreamFactory implements Serializable {
   }
   
   public boolean doesRepresentTypes(StreamExpression expression, Class ... clazzes){
-    if(functionNames.containsKey(expression.getFunctionName())){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(expression.getFunctionName());
+    if(classSupplier != null){
       for(Class clazz : clazzes){
-        if(!clazz.isAssignableFrom(functionNames.get(expression.getFunctionName()))){
+        if(!clazz.isAssignableFrom(classSupplier.get())){
           return false;
         }
       }
@@ -203,7 +213,7 @@ public class StreamFactory implements Serializable {
   
   public int getIntOperand(StreamExpression expression, String paramName, Integer defaultValue) throws IOException{
     StreamExpressionNamedParameter param = getNamedOperand(expression, paramName);
-    
+
     if(null == param || null == param.getParameter() || !(param.getParameter() instanceof StreamExpressionValue)){
       if(null != defaultValue){
         return defaultValue;
@@ -241,10 +251,12 @@ public class StreamFactory implements Serializable {
   }
   public TupleStream constructStream(StreamExpression expression) throws IOException{
     String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
-      Class<? extends Expressible> clazz = functionNames.get(function);
+
+    if(classSupplier != null){
+      Class<? extends Expressible> clazz =  classSupplier.get();
       if(Expressible.class.isAssignableFrom(clazz) && TupleStream.class.isAssignableFrom(clazz)){
-        return (TupleStream)createInstance(functionNames.get(function), new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
+        return (TupleStream)createInstance(clazz, new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
       }
     }
     
@@ -256,10 +268,11 @@ public class StreamFactory implements Serializable {
   }
   public Metric constructMetric(StreamExpression expression) throws IOException{
     String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
-      Class<? extends Expressible> clazz = functionNames.get(function);
+    if(classSupplier != null){
+      Class<? extends Expressible> clazz = classSupplier.get();
       if(Expressible.class.isAssignableFrom(clazz) && Metric.class.isAssignableFrom(clazz)){
-        return (Metric)createInstance(functionNames.get(function), new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
+        return (Metric)createInstance(clazz, new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
       }
     }
     
@@ -356,16 +369,18 @@ public class StreamFactory implements Serializable {
   public Metric constructOperation(String expressionClause) throws IOException {
     return constructMetric(StreamExpressionParser.parse(expressionClause));
   }
-  public StreamOperation constructOperation(StreamExpression expression) throws IOException{
+
+  public StreamOperation constructOperation(StreamExpression expression) throws IOException {
     String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
-      Class<? extends Expressible> clazz = functionNames.get(function);
+    if (classSupplier != null) {
-      if(Expressible.class.isAssignableFrom(clazz) && StreamOperation.class.isAssignableFrom(clazz)){
+      Class<? extends Expressible> clazz = classSupplier.get();
-        return (StreamOperation)createInstance(functionNames.get(function), new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
+      if (Expressible.class.isAssignableFrom(clazz) && StreamOperation.class.isAssignableFrom(clazz)) {
+        return (StreamOperation) createInstance(clazz, new Class[]{StreamExpression.class, StreamFactory.class}, new Object[]{expression, this});
       }
     }
-    
+
-    throw new IOException(String.format(Locale.ROOT,"Invalid operation expression %s - function '%s' is unknown (not mapped to a valid StreamOperation)", expression, expression.getFunctionName()));
+    throw new IOException(String.format(Locale.ROOT, "Invalid operation expression %s - function '%s' is unknown (not mapped to a valid StreamOperation)", expression, expression.getFunctionName()));
   }
   
   public org.apache.solr.client.solrj.io.eval.StreamEvaluator constructEvaluator(String expressionClause) throws IOException {
@@ -373,33 +388,24 @@ public class StreamFactory implements Serializable {
   }
   public org.apache.solr.client.solrj.io.eval.StreamEvaluator constructEvaluator(StreamExpression expression) throws IOException{
     String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
-      Class<? extends Expressible> clazz = functionNames.get(function);
+
+    if(classSupplier != null){
+      Class<? extends Expressible> clazz = classSupplier.get();
       if(Expressible.class.isAssignableFrom(clazz) && StreamEvaluator.class.isAssignableFrom(clazz)){
-        return (org.apache.solr.client.solrj.io.eval.StreamEvaluator)createInstance(functionNames.get(function), new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
+        return (org.apache.solr.client.solrj.io.eval.StreamEvaluator)createInstance(clazz, new Class[]{ StreamExpression.class, StreamFactory.class }, new Object[]{ expression, this});
       }
     }
     
     throw new IOException(String.format(Locale.ROOT,"Invalid evaluator expression %s - function '%s' is unknown (not mapped to a valid StreamEvaluator)", expression, expression.getFunctionName()));
   }
 
-  public boolean isStream(StreamExpression expression) throws IOException{
+  public boolean isStream(StreamExpression expression) throws IOException {
     String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
-      Class<? extends Expressible> clazz = functionNames.get(function);
+    if (classSupplier != null) {
-      if(Expressible.class.isAssignableFrom(clazz) && TupleStream.class.isAssignableFrom(clazz)){
+      Class<? extends Expressible> clazz = classSupplier.get();
-        return true;
+      if (Expressible.class.isAssignableFrom(clazz) && TupleStream.class.isAssignableFrom(clazz)) {
-      }
-    }
-
-    return false;
-  }
-  
-  public boolean isEvaluator(StreamExpression expression) throws IOException{
-    String function = expression.getFunctionName();
-    if(functionNames.containsKey(function)){
-      Class<? extends Expressible> clazz = functionNames.get(function);
-      if(Expressible.class.isAssignableFrom(clazz) && StreamEvaluator.class.isAssignableFrom(clazz)){
         return true;
       }
     }
@@ -407,35 +413,48 @@ public class StreamFactory implements Serializable {
     return false;
   }
 
-  public <T> T createInstance(Class<T> clazz, Class<?>[] paramTypes, Object[] params) throws IOException{
+  public boolean isEvaluator(StreamExpression expression) throws IOException {
+    String function = expression.getFunctionName();
+    Supplier<Class<? extends Expressible>> classSupplier = functionNames.get(function);
+    if (classSupplier != null) {
+      Class<? extends Expressible> clazz = classSupplier.get();
+      if (Expressible.class.isAssignableFrom(clazz) && StreamEvaluator.class.isAssignableFrom(clazz)) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  public <T> T createInstance(Class<T> clazz, Class<?>[] paramTypes, Object[] params) throws IOException {
     Constructor<T> ctor;
     try {
       ctor = clazz.getConstructor(paramTypes);
       return ctor.newInstance(params);
-      
+
     } catch (NoSuchMethodException | SecurityException | InstantiationException | IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
-      if(null != e.getMessage()){
+      if (null != e.getMessage()) {
-        throw new IOException(String.format(Locale.ROOT,"Unable to construct instance of %s caused by %s", clazz.getName(), e.getMessage()),e);
+        throw new IOException(String.format(Locale.ROOT, "Unable to construct instance of %s caused by %s", clazz.getName(), e.getMessage()), e);
-      }
+      } else {
-      else{
+        throw new IOException(String.format(Locale.ROOT, "Unable to construct instance of %s", clazz.getName()), e);
-        throw new IOException(String.format(Locale.ROOT,"Unable to construct instance of %s", clazz.getName()),e);
       }
     }
   }
-  
+
-  public String getFunctionName(Class<? extends Expressible> clazz) throws IOException{
+  public String getFunctionName(Class<? extends Expressible> clazz) throws IOException {
-    for(Entry<String,Class<? extends Expressible>> entry : functionNames.entrySet()){
+    for (Entry<String, Supplier<Class<? extends Expressible>>> entry : functionNames.entrySet()) {
-      if(entry.getValue() == clazz){
+      if (entry.getValue().get() == clazz) {
         return entry.getKey();
       }
     }
-    
+
+
     throw new IOException(String.format(Locale.ROOT, "Unable to find function name for class '%s'", clazz.getName()));
   }
-  
+
   public Object constructPrimitiveObject(String original){
     String lower = original.trim().toLowerCase(Locale.ROOT);
-    
+
     if("null".equals(lower)){ return null; }
     if("true".equals(lower) || "false".equals(lower)){ return Boolean.parseBoolean(lower); }
     try{ return Long.valueOf(original); } catch(Exception ignored){};

solr/solrj/src/test/org/apache/solr/client/solrj/io/TestLang.java

@@ -20,6 +20,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Supplier;
 
 import org.apache.lucene.util.LuceneTestCase;
 import org.apache.lucene.util.LuceneTestCase.Slow;
@@ -94,7 +95,7 @@ public class TestLang extends SolrTestCase {
     }
     StreamFactory factory = new StreamFactory();
     Lang.register(factory);
-    Map<String,Class<? extends Expressible>> registeredFunctions = factory.getFunctionNames();
+    Map<String, Supplier<Class<? extends Expressible>>> registeredFunctions = factory.getFunctionNames();
 
     //Check that each function that is expected is registered.
     for(String func : functions) {