SOLR-647: refcount cores

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@686780 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -358,6 +358,9 @@ Changes in runtime behavior
    1.3 release.  Speciffically, solr.xml has replaced multicore.xml, and uses a slightly 
    different syntax.  The solrj classes: MultiCore{Request/Response/Params} have been 
    renamed:  CoreAdmin{Request/Response/Params}  (hossman, ryan, Henri Biestro)
+
+ 3. SOLR-647: reference count the SolrCore uses to prevent a premature
+    close while a core is still in use.  (Henri Biestro, Noble Paul, yonik)
     
 Optimizations
  1. SOLR-276: improve JSON writer speed. (yonik)

client/java/solrj/src/org/apache/solr/client/solrj/embedded/EmbeddedSolrServer.java

@@ -36,6 +36,7 @@ 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.SolrCore;
+import org.apache.solr.core.CoreDescriptor;
 import org.apache.solr.request.BinaryResponseWriter;
 import org.apache.solr.request.QueryResponseWriter;
 import org.apache.solr.request.SolrQueryRequest;
@@ -54,38 +55,46 @@ import org.apache.solr.servlet.SolrRequestParsers;
  */
 public class EmbeddedSolrServer extends SolrServer
 {
-  
+  protected final CoreContainer coreContainer;
-  protected final CoreContainer multicore; // either cores
+  protected final String coreName;
-  protected final SolrCore core; // or single core
-  protected final String coreName;  // use CoreContainer registry
-
   private final SolrRequestParsers _parser;
   
+  /**
+   * Use the other constructor using a CoreContainer and a name.
+   * @param core
+   * @deprecated
+   */
+  @Deprecated
   public EmbeddedSolrServer( SolrCore core )
   {
     if ( core == null ) {
       throw new NullPointerException("SolrCore instance required");
     }
-    this.core = core;
+    CoreDescriptor dcore = core.getCoreDescriptor();
-    if (core.getCoreDescriptor() != null) {
+    if (dcore == null)
-      this.multicore = core.getCoreDescriptor().getMultiCore();
+      throw new NullPointerException("CoreDescriptor required");
-      this.coreName = core.getCoreDescriptor().getName();
+    
-    } else {
+    CoreContainer cores = dcore.getCoreContainer();
-      this.multicore = null;
+    if (cores == null)
-      this.coreName = null;
+      throw new NullPointerException("CoreContainer required");
-    }
+    
+    coreName = dcore.getName();
+    coreContainer = cores;
     _parser = new SolrRequestParsers( null );
   }
     
-  public EmbeddedSolrServer(  CoreContainer multicore, String coreName )
+  /**
+   * Creates a SolrServer.
+   * @param coreContainer the core container
+   * @param coreName the core name
+   */
+  public EmbeddedSolrServer(  CoreContainer coreContainer, String coreName )
   {
-    if ( multicore == null ) {
+    if ( coreContainer == null ) {
       throw new NullPointerException("CoreContainer instance required");
     }
-    this.core = null;
+    this.coreContainer = coreContainer;
-    this.multicore = multicore;
     this.coreName = coreName == null? "" : coreName;
-
     _parser = new SolrRequestParsers( null );
   }
   
@@ -98,15 +107,10 @@ public class EmbeddedSolrServer extends SolrServer
     }
 
     // Check for cores action
-    SolrCore core = this.core;
+    SolrCore core =  coreContainer.getCore( coreName );
-    if( core == null )
-      core = multicore.getCore( coreName );
-    // solr-647
-    //else
-    //  core = core.open();
     if( core == null ) {
       throw new SolrException( SolrException.ErrorCode.SERVER_ERROR, 
-          coreName == null? "No core": "No such core: " + coreName );
+                               "No such core: " + coreName );
     }
     
     SolrParams params = request.getParams();
@@ -126,14 +130,13 @@ public class EmbeddedSolrServer extends SolrServer
       }
       // Perhaps the path is to manage the cores
       if( handler == null &&
-          multicore != null &&
+          coreContainer != null &&
-          path.equals( multicore.getAdminPath() ) ) {
+          path.equals( coreContainer.getAdminPath() ) ) {
-        handler = multicore.getMultiCoreHandler();
+        handler = coreContainer.getMultiCoreHandler();
       }
     }
     if( handler == null ) {
-      // solr-647
+      core.close();
-      // core.close();
       throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "unknown handler: "+path );
     }
 
@@ -158,8 +161,7 @@ public class EmbeddedSolrServer extends SolrServer
       throw new SolrServerException( ex );
     }
     finally {
-      // solr-647
+      core.close();
-      // core.close();
     }
   }
   

client/java/solrj/test/org/apache/solr/client/solrj/embedded/LargeVolumeEmbeddedTest.java

@@ -45,6 +45,6 @@ public class LargeVolumeEmbeddedTest extends LargeVolumeTestBase {
   @Override
   protected SolrServer createNewSolrServer()
   {
-    return new EmbeddedSolrServer( h.getCore() );
+    return new EmbeddedSolrServer( h.getCoreContainer(), "" );
   }
 }

client/java/solrj/test/org/apache/solr/client/solrj/embedded/SolrExampleEmbeddedTest.java

@@ -47,6 +47,6 @@ public class SolrExampleEmbeddedTest extends SolrExampleTests {
   @Override
   protected SolrServer createNewSolrServer()
   {
-    return new EmbeddedSolrServer( h.getCore() );
+    return new EmbeddedSolrServer( h.getCoreContainer(), "" );
   }
 }

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

@@ -25,9 +25,7 @@ import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.nio.channels.FileChannel;
-import java.util.Collection;
+import java.util.*;
-import java.util.LinkedHashMap;
-import java.util.Map;
 import java.util.logging.Logger;
 
 import javax.xml.parsers.ParserConfigurationException;
@@ -36,6 +34,7 @@ import javax.xml.xpath.XPathConstants;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.util.DOMUtil;
 import org.apache.solr.common.util.XML;
+import org.apache.solr.common.util.StrUtils;
 import org.apache.solr.handler.admin.CoreAdminHandler;
 import org.apache.solr.schema.IndexSchema;
 import org.w3c.dom.Node;
@@ -51,7 +50,7 @@ public class CoreContainer
 {
   protected static Logger log = Logger.getLogger(CoreContainer.class.getName());
   
-  protected final Map<String, CoreDescriptor> cores = new LinkedHashMap<String, CoreDescriptor>();
+  protected final Map<String, SolrCore> cores = new LinkedHashMap<String, SolrCore>();
   protected boolean persistent = false;
   protected String adminPath = null;
   protected String managementPath = null;
@@ -69,8 +68,7 @@ public class CoreContainer
   public static class Initializer {
     protected String solrConfigFilename = null;
     protected boolean abortOnConfigurationError = true;
-    protected String managementPath = null;
+
-    
     public boolean isAbortOnConfigurationError() {
       return abortOnConfigurationError;
     }
@@ -86,14 +84,6 @@ public class CoreContainer
     public void setSolrConfigFilename(String solrConfigFilename) {
       this.solrConfigFilename = solrConfigFilename;
     }
-    
-    public String getManagementPath() {
-      return managementPath;
-    }
-
-    public void setManagementPath(String managementPath) {
-      this.managementPath = managementPath;
-    }
 
     // core container instantiation
     public CoreContainer initialize() throws IOException, ParserConfigurationException, SAXException {
@@ -116,16 +106,13 @@ public class CoreContainer
         solrConfigFilename = cores.getConfigFile().getName();
       } else {
         // perform compatibility init
-        cores = new CoreContainer();
+        cores = new CoreContainer(new SolrResourceLoader(instanceDir));
-        cores.loader = new SolrResourceLoader(instanceDir);
         SolrConfig cfg = solrConfigFilename == null ? new SolrConfig() : new SolrConfig(solrConfigFilename);
-        CoreDescriptor dcore = new CoreDescriptor(cores);
+        CoreDescriptor dcore = new CoreDescriptor(cores, "", cfg.getResourceLoader().getInstanceDir());
-        dcore.init("", cfg.getResourceLoader().getInstanceDir());
         SolrCore singlecore = new SolrCore(null, null, cfg, null, dcore);
-        dcore.setCore(singlecore);
         abortOnConfigurationError = cfg.getBool(
                 "abortOnConfigurationError", abortOnConfigurationError);
-        cores.register(dcore);
+        cores.register("", singlecore, false);
         cores.setPersistent(false);
         solrConfigFilename = cfg.getName();
       }
@@ -147,6 +134,14 @@ public class CoreContainer
     this.load(dir, configFile);
   }
   
+  /**
+   * Minimal CoreContainer constructor. 
+   * @param loader the CoreContainer resource loader
+   */
+  public CoreContainer(SolrResourceLoader loader) {
+    this.loader = loader;
+  }
+  
   //-------------------------------------------------------------------
   // Initialization / Cleanup
   //-------------------------------------------------------------------
@@ -165,54 +160,60 @@ public class CoreContainer
     FileInputStream cfgis = new FileInputStream(configFile);
     try {
       Config cfg = new Config(loader, null, cfgis, null);
-    
+
       persistent = cfg.getBool( "solr/@persistent", false );
       libDir     = cfg.get(     "solr/@sharedLib", null);
       adminPath  = cfg.get(     "solr/cores/@adminPath", null );
       managementPath  = cfg.get("solr/cores/@managementPath", null );
-      
+
       if (libDir != null) {
         // relative dir to conf
         File f = new File(dir, libDir);
-        libDir = f.getPath(); 
+        libDir = f.getPath();
         log.info( "loading shared library: "+f.getAbsolutePath() );
         libLoader = SolrResourceLoader.createClassLoader(f, null);
       }
-      
+
       if( adminPath != null ) {
         coreAdminHandler = this.createMultiCoreHandler();
       }
-      
+
       NodeList nodes = (NodeList)cfg.evaluate("solr/cores/core", XPathConstants.NODESET);
-      synchronized (cores) {
+
-        for (int i=0; i<nodes.getLength(); i++) {
+      for (int i=0; i<nodes.getLength(); i++) {
-          Node node = nodes.item(i);
+        Node node = nodes.item(i);
-          try {
+        try {
-            CoreDescriptor p = new CoreDescriptor(this);
+          String names = DOMUtil.getAttr(node, "name", null);
-            p.init(DOMUtil.getAttr(node, "name", null), DOMUtil.getAttr(node, "instanceDir", null));
+          List<String> aliases = StrUtils.splitSmart(names,',');
-            // deal with optional settings
+          String name = aliases.get(0);
-            String opt = DOMUtil.getAttr(node, "config", null);
+          CoreDescriptor p = new CoreDescriptor(this, name, DOMUtil.getAttr(node, "instanceDir", null));
-            if (opt != null) {
+
-              p.setConfigName(opt);
+          // deal with optional settings
-            }
+          String opt = DOMUtil.getAttr(node, "config", null);
-            opt = DOMUtil.getAttr(node, "schema", null);
+          if (opt != null) {
-            if (opt != null) {
+            p.setConfigName(opt);
-              p.setSchemaName(opt);
-            }
-            CoreDescriptor old = cores.get(p.getName());
-            if (old != null && old.getName() != null && old.getName().equals(p.getName())) {
-              throw new RuntimeException( cfg.getName() +
-                " registers multiple cores to the same name: " + p.name);
-            }
-            p.setCore(create(p));
           }
-          catch (Throwable ex) {
+          opt = DOMUtil.getAttr(node, "schema", null);
-            SolrConfig.severeErrors.add( ex );
+          if (opt != null) {
-            SolrException.logOnce(log,null,ex);
+            p.setSchemaName(opt);
           }
+
+          SolrCore core = create(p);
+
+          for (int a=1; a<aliases.size(); a++) {
+            core.open();
+            register(aliases.get(i), core, false);
+          }
+
+          register(name, core, false);
+        }
+        catch (Throwable ex) {
+          SolrConfig.severeErrors.add( ex );
+          SolrException.logOnce(log,null,ex);
         }
       }
     }
+
     finally {
       if (cfgis != null) {
         try { cfgis.close(); } catch (Exception xany) {}
@@ -225,11 +226,8 @@ public class CoreContainer
    */
   public void shutdown() {
     synchronized(cores) {
-      for(CoreDescriptor descriptor : cores.values()) {
+      for(SolrCore core : cores.values()) {
-        SolrCore core = descriptor.getCore();
+        core.close();
-        if( core != null ) {
-          core.close();
-        }
       }
       cores.clear();
     }
@@ -239,40 +237,44 @@ public class CoreContainer
   protected void finalize() {
     shutdown();
   }
-  
+
-  // ---------------- CoreDescriptor related methods --------------- 
   /**
    * Registers a SolrCore descriptor in the registry.
-   * @param descr the Solr core descriptor
+   * @return a previous core having the same name if it existed and returnPrev==true
-   * @return a previous descriptor having the same name if it existed, null otherwise
    */
-  public CoreDescriptor register( CoreDescriptor descr ) {
+  public SolrCore register(String name, SolrCore core, boolean returnPrev) {
-    if( descr == null ) {
+    if( core == null ) {
       throw new RuntimeException( "Can not register a null core." );
     }
-    String name = descr.getName();
+    if( name == null ||
-    if( name == null || 
         name.indexOf( '/'  ) >= 0 ||
         name.indexOf( '\\' ) >= 0 ){
       throw new RuntimeException( "Invalid core name: "+name );
     }
 
-    CoreDescriptor old = null;    
+    SolrCore old = null;
     synchronized (cores) {
-      old = cores.put(name, descr);
+      old = cores.put(name, core);
+      core.setName(name);
     }
-    if( old == null ) {
+
+
+    if( old == null || old == core) {
       log.info( "registering core: "+name );
       return null;
-    } 
+    }
     else {
       log.info( "replacing core: "+name );
+      if (!returnPrev) {
+        old.close();
+      }
       return old;
     }
   }
 
+
   /**
-   * Creates a new core based on a descriptor.
+   * Creates a new core based on a descriptor but does not register it.
    *
    * @param dcore a core descriptor
    * @return the newly created core
@@ -293,10 +295,6 @@ public class CoreContainer
     SolrConfig config = new SolrConfig(solrLoader, dcore.getConfigName(), null);
     IndexSchema schema = new IndexSchema(config, dcore.getSchemaName(), null);
     SolrCore core = new SolrCore(dcore.getName(), null, config, schema, dcore);
-    dcore.setCore(core);
-    
-    // Register the new core
-    CoreDescriptor old = this.register(dcore);
     return core;
   }
     
@@ -304,37 +302,39 @@ public class CoreContainer
    * @return a Collection of registered SolrCores
    */
   public Collection<SolrCore> getCores() {
-    java.util.List<SolrCore> l = new java.util.ArrayList<SolrCore>();
+    List<SolrCore> lst = new ArrayList<SolrCore>();
     synchronized (cores) {
-      for(CoreDescriptor descr : this.cores.values()) {
+      lst.addAll(this.cores.values());
-        if (descr.getCore() != null)
-          l.add(descr.getCore());
-      }
     }
-    return l;
+    return lst;
-  }
-    
-  /**
-   * @return a Collection of registered CoreDescriptors
-   */
-  public Collection<CoreDescriptor> getDescriptors() {
-   java.util.List<CoreDescriptor> l = new java.util.ArrayList<CoreDescriptor>();
-   synchronized (cores) {
-     l.addAll(cores.values());
-   }
-   return l;
   }
 
   /**
-   * @return the CoreDescriptor registered under that name
+   * @return a Collection of the names that cores are mapped to
    */
-  public CoreDescriptor getDescriptor(String name) {
+  public Collection<String> getCoreNames() {
-    synchronized(cores) {
+    List<String> lst = new ArrayList<String>();
-      return cores.get( name );
+    synchronized (cores) {
+      lst.addAll(this.cores.keySet());
     }
+    return lst;
   }
-  
+
-  
+  /**
+   * @return a Collection of the names that a specific core is mapped to.
+   */
+  public Collection<String> getCoreNames(SolrCore core) {
+    List<String> lst = new ArrayList<String>();
+    synchronized (cores) {
+      for (Map.Entry<String,SolrCore> entry : cores.entrySet()) {
+        if (core == entry.getValue()) {
+          lst.add(entry.getKey());
+        }
+      }
+    }
+    return lst;
+  }
+
   // ---------------- Core name related methods --------------- 
   /**
    * Recreates a SolrCore.
@@ -348,12 +348,14 @@ public class CoreContainer
    */
 
   public void reload(String name) throws ParserConfigurationException, IOException, SAXException {
+    SolrCore core;
     synchronized(cores) {
-      CoreDescriptor dcore = cores.get(name);
+      core = cores.get(name);
-      if (dcore == null)
-        throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "No such core: " + name );   
-      create(new CoreDescriptor(dcore));
     }
+    if (core == null)
+      throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "No such core: " + name );
+
+    register(name, create(core.getCoreDescriptor()), false);
   }
     
   
@@ -367,36 +369,27 @@ public class CoreContainer
       throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "Can not swap unnamed cores." );
     }
     synchronized( cores ) {
-      CoreDescriptor c0 = cores.get(n0);
+      SolrCore c0 = cores.get(n0);
+      SolrCore c1 = cores.get(n1);
       if (c0 == null)
         throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "No such core: " + n0 );
-      CoreDescriptor c1 = cores.get(n1);
       if (c1 == null)
         throw new SolrException( SolrException.ErrorCode.BAD_REQUEST, "No such core: " + n1 );
       cores.put(n0, c1);
       cores.put(n1, c0);
-      c0.setName( n1 );
+
-      if (c0.getCore() != null)
+      c0.setName(n1);
-        c0.getCore().setName(n1);
+      c1.setName(n0);
-      c1.setName( n0 );
-      if (c1.getCore() != null)
-        c1.getCore().setName(n0);
-      log.info( "swaped: "+c0.getName() + " with " + c1.getName() );
     }
+
+
+    log.info("swaped: "+n0 + " with " + n1);
   }
   
-  /** Removes & closes a registered core. */
+  /** Removes and returns registered core w/o decrementing it's reference count */
-  public void remove( String name ) {
+  public SolrCore remove( String name ) {
     synchronized(cores) {
-      CoreDescriptor dcore = cores.remove( name );
+      return cores.remove( name );
-      if (dcore == null) {
-        return;
-      }
-      
-      SolrCore core = dcore.getCore();
-      if (core != null) {
-        core.close();
-      }
     }
   }
 
@@ -408,15 +401,10 @@ public class CoreContainer
    */
   public SolrCore getCore(String name) {
     synchronized(cores) {
-      CoreDescriptor dcore = cores.get(name);
+      SolrCore core = cores.get(name);
-       SolrCore core = null;
+      if (core != null)
-      if (dcore != null)
+        core.open();  // increment the ref count while still synchronized
-        core = dcore.getCore();
+      return core;
-       return core;
-// solr-647
-//      if (core != null)
-//        return core.open();
-//      return null;
     }
   }
 
@@ -433,20 +421,17 @@ public class CoreContainer
    * Ensures there is a valid core to handle MultiCore admin taks and
    * increase its refcount.
    * @return the acquired admin core, null if no core is available
-   */
+   */               
   public SolrCore getAdminCore() {
     synchronized (cores) {
       SolrCore core = adminCore != null ? adminCore.get() : null;
-//      solr-647
+      if (core != null) {
-//      if (core != null)
+        core.open();
-//        core = core.open();
+      } else {
-      if (core == null) {
+        for (SolrCore c : cores.values()) {
-        for (CoreDescriptor descr : this.cores.values()) {
+          if (c != null) {
-          core = descr.getCore();
+            core = c;
-//          solr-647
+            core.open();
-//          if (core != null)
-//            core = core.open();
-          if (core != null) {
             break;
           }
         }
@@ -517,7 +502,7 @@ public class CoreContainer
   public void persist() {
     persistFile(null);
   }
-  
+
   /** Persists the cores config file in a user provided file. */
   public void persistFile(File file) {
     File tmpFile = null;
@@ -527,7 +512,6 @@ public class CoreContainer
         file = tmpFile = File.createTempFile("solr", ".xml", configFile.getParentFile());
       }
       java.io.FileOutputStream out = new java.io.FileOutputStream(file);
-      synchronized(cores) {
         Writer writer = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
         persist(writer);
         writer.flush();
@@ -540,7 +524,6 @@ public class CoreContainer
           else
             fileCopy(tmpFile, configFile);
         }
-      }
     } 
     catch(java.io.FileNotFoundException xnf) {
       throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, xnf);
@@ -578,20 +561,35 @@ public class CoreContainer
     writer.write('\'');
     writer.write(">\n");
 
+    Map<SolrCore, LinkedList<String>> aliases = new HashMap<SolrCore,LinkedList<String>>();
+
     synchronized(cores) {
-      for (Map.Entry<String, CoreDescriptor> entry : cores.entrySet()) {
+      for (Map.Entry<String, SolrCore> entry : cores.entrySet()) {
-        persist(writer, entry.getValue());
+        String name = entry.getKey();
+        LinkedList<String> a = aliases.get(entry.getValue());
+        if (a==null) a = new LinkedList<String>();
+        if (name.equals(entry.getValue().getName())) {
+          a.addFirst(name);
+        } else {
+          a.addLast(name);
+        }
+        aliases.put(entry.getValue(), a);
       }
     }
+
+    for (Map.Entry<SolrCore, LinkedList<String>> entry : aliases.entrySet()) {
+      persist(writer, entry.getValue(), entry.getKey().getCoreDescriptor());
+    }
+
     writer.write("</cores>\n");
     writer.write("</solr>\n");
   }
   
   /** Writes the cores configuration node for a given core. */
-  void persist(Writer writer, CoreDescriptor dcore) throws IOException {
+  void persist(Writer writer, List<String> aliases, CoreDescriptor dcore) throws IOException {
     writer.write("  <core");
     writer.write (" name='");
-    XML.escapeAttributeValue(dcore.getName(), writer);
+    XML.escapeAttributeValue(StrUtils.join(aliases,','), writer);
     writer.write("' instanceDir='");
     XML.escapeAttributeValue(dcore.getInstanceDir(), writer);
     writer.write('\'');

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

@@ -28,22 +28,17 @@ public class CoreDescriptor implements Cloneable {
   protected String instanceDir;
   protected String configName;
   protected String schemaName;
-  protected SolrCore core = null;
   private final CoreContainer coreContainer;
 
-  public CoreDescriptor(CoreContainer coreContainer) {
+  public CoreDescriptor(CoreContainer coreContainer, String name, String instanceDir) {
     this.coreContainer = coreContainer;
-  }
+    this.name = name;
-
-  /** Initialize defaults from instance directory. */
-  public void init(String name, String instanceDir) {
     if (name == null) {
       throw new RuntimeException("Core needs a name");
     }
     if (instanceDir == null) {
       throw new NullPointerException("Missing required \'instanceDir\'");
     }
-    this.name = name;
     if (!instanceDir.endsWith("/")) instanceDir = instanceDir + "/";
     this.instanceDir = instanceDir;
     this.configName = getDefaultConfigName();
@@ -51,10 +46,10 @@ public class CoreDescriptor implements Cloneable {
   }
 
   public CoreDescriptor(CoreDescriptor descr) {
-    this.name = descr.name;
     this.instanceDir = descr.instanceDir;
     this.configName = descr.configName;
     this.schemaName = descr.schemaName;
+    this.name = descr.name;
     coreContainer = descr.coreContainer;
   }
   
@@ -72,17 +67,7 @@ public class CoreDescriptor implements Cloneable {
   public String getDefaultDataDir() {
     return this.instanceDir + "data/";
   }
-  
+ 
-  /**@return the core name. */
-  public String getName() {
-    return name;
-  }
-  
-  /** Sets the core name. */
-  public void setName(String name) {
-    this.name = name;
-  }
-  
   /**@return the core instance directory. */
   public String getInstanceDir() {
     return instanceDir;
@@ -111,16 +96,13 @@ public class CoreDescriptor implements Cloneable {
   public String getSchemaName() {
     return this.schemaName;
   }
-  
+
-  public SolrCore getCore() {
+  /**@return the initial core name */
-    return core;
+  public String getName() {
-  }
+    return this.name;
-  
-  public void setCore(SolrCore core) {
-    this.core = core;
   }
 
-  public CoreContainer getMultiCore() {
+  public CoreContainer getCoreContainer() {
     return coreContainer;
   }
 }

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

@@ -62,13 +62,15 @@ import java.io.File;
 import java.io.IOException;
 import java.util.*;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.logging.Logger;
+import java.net.URL;
 
 
 /**
  * @version $Id$
  */
-public final class SolrCore {
+public final class SolrCore implements SolrInfoMBean {
   public static final String version="1.0";  
 
   public static Logger log = Logger.getLogger(SolrCore.class.getName());
@@ -374,7 +376,7 @@ public final class SolrCore {
    * @since solr 1.0
    */
   public SolrCore(String dataDir, IndexSchema schema) throws ParserConfigurationException, IOException, SAXException {
-    this( null, dataDir, new SolrConfig(), schema, null );
+    this(null, dataDir, new SolrConfig(), schema, null );
   }
   
   /**
@@ -479,8 +481,9 @@ public final class SolrCore {
         latch.countDown();
       }
     } // end synchronized
+
+    infoRegistry.put("core", this);
   }
-  
 
 
   /**
@@ -569,16 +572,39 @@ public final class SolrCore {
     }
     return chain;
   }
+  
+  // this core current usage count
+  private final AtomicInteger refCount = new AtomicInteger(1);
 
+  final void open() {
+    refCount.incrementAndGet();
+  }
+  
   /**
    * Close all resources allocated by the core.
    *  1. searcher
    *  2. updateHandler
    *  3. all CloseHooks will be notified
    *  4. All MBeans will be unregistered from MBeanServer if JMX was enabled
+   * <p>
+   * This should always be called when the core is obtained through:
+   * @see CoreContainer.getCore
+   * @see CoreContainer.getAdminCore
+   * </p>
+   * The actual close is performed if the core usage count is 1.
+   * (A core is created with a usage count of 1).
+   * If usage count is > 1, the usage count is decreased by 1.
+   * If usage count is &lt; 0, this is an error and a runtime exception is thrown.
    */
   public void close() {
-    log.info(logid+" CLOSING SolrCore!");
+    int count = refCount.decrementAndGet();
+    if (count > 0) return;
+    if (count < 0) {
+      //throw new RuntimeException("Too many closes on " + this);
+      log.severe("Too many close {count:"+count+"} on " + this + ". Please report this exception to solr-user@lucene.apache.org");
+      return;
+    }
+    log.info(logid+" CLOSING SolrCore " + this);
     try {
       infoRegistry.clear();
     } catch (Exception e) {
@@ -602,16 +628,22 @@ public final class SolrCore {
     if( closeHooks != null ) {
        for( CloseHook hook : closeHooks ) {
          hook.close( this );
-       }
+      }
     }
   }
 
-  public boolean isClosed() {
+  /** Current core usage count. */
-    return _searcher == null;
+  public int getOpenCount() {
+    return refCount.get();
   }
   
-  @Override
+  /** Whether this core is closed. */
-  protected void finalize() { close(); }
+  public boolean isClosed() {
+      return refCount.get() <= 0;
+  }
+  
+  // this can cause an extra close
+  // protected void finalize() { close(); }
 
   private List<CloseHook> closeHooks = null;
 
@@ -1380,6 +1412,45 @@ public final class SolrCore {
   public CoreDescriptor getCoreDescriptor() {
     return coreDescriptor;
   }
+
+
+  /////////////////////////////////////////////////////////////////////
+  // SolrInfoMBean stuff: Statistics and Module Info
+  /////////////////////////////////////////////////////////////////////
+
+  public String getVersion() {
+    return SolrCore.version;
+  }
+
+  public String getDescription() {
+    return "SolrCore";
+  }
+
+  public Category getCategory() {
+    return Category.CORE;
+  }
+
+  public String getSourceId() {
+    return "$Id:$";
+  }
+
+  public String getSource() {
+    return "$URL:$";
+  }
+
+  public URL[] getDocs() {
+    return null;
+  }
+
+  public NamedList getStatistics() {
+    NamedList lst = new SimpleOrderedMap();
+    lst.add("coreName", name==null ? "(null)" : name);
+    lst.add("startTime", new Date(startTime));
+    lst.add("refCount", getOpenCount());
+    lst.add("aliases", getCoreDescriptor().getCoreContainer().getCoreNames(this));
+    return lst;
+  }
+
 }
 
 

src/java/org/apache/solr/handler/admin/CoreAdminHandler.java

@@ -90,9 +90,8 @@ public abstract class CoreAdminHandler extends RequestHandlerBase
     
     switch(action) {
       case CREATE: {
-        CoreDescriptor dcore = new CoreDescriptor(cores);
+        String name = params.get(CoreAdminParams.NAME);
-        dcore.init(params.get(CoreAdminParams.NAME),
+        CoreDescriptor dcore = new CoreDescriptor(cores, name, params.get(CoreAdminParams.INSTANCE_DIR));
-                  params.get(CoreAdminParams.INSTANCE_DIR));
 
         // fillup optional parameters
         String opts = params.get(CoreAdminParams.CONFIG);
@@ -104,6 +103,7 @@ public abstract class CoreAdminHandler extends RequestHandlerBase
           dcore.setSchemaName(opts);
 
         SolrCore core = cores.create(dcore);
+        cores.register(name, core,false);
         rsp.add("core", core.getName());
         do_persist = cores.isPersistent();
         break;
@@ -112,9 +112,8 @@ public abstract class CoreAdminHandler extends RequestHandlerBase
       case STATUS: {
         NamedList<Object> status = new SimpleOrderedMap<Object>();
         if( cname == null ) {
-          for (CoreDescriptor d : cores.getDescriptors()) {
+          for (SolrCore core : cores.getCores()) {
-            cname = d.getName();
+            status.add(core.getName(), getCoreStatus( cores, cname  ) );
-            status.add(d.getName(), getCoreStatus( cores, cname  ) );
           }
         } 
         else {
@@ -172,8 +171,7 @@ public abstract class CoreAdminHandler extends RequestHandlerBase
         info.add("index", LukeRequestHandler.getIndexInfo(searcher.get().getReader(), false));
         searcher.decref();
       } finally {
-        // solr-647
+        core.close();
-        // core.close();
       }
     }
     return info;

src/java/org/apache/solr/util/TestHarness.java

@@ -21,6 +21,9 @@ import org.apache.solr.common.util.NamedList;
 import org.apache.solr.common.util.XML;
 import org.apache.solr.core.SolrConfig;
 import org.apache.solr.core.SolrCore;
+import org.apache.solr.core.CoreContainer;
+import org.apache.solr.core.CoreDescriptor;
+import org.apache.solr.core.SolrResourceLoader;
 import org.apache.solr.handler.XmlUpdateRequestHandler;
 import org.apache.solr.request.LocalSolrQueryRequest;
 import org.apache.solr.request.QueryResponseWriter;
@@ -32,6 +35,7 @@ import org.xml.sax.SAXException;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.xpath.XPath;
 import javax.xml.xpath.XPathConstants;
 import javax.xml.xpath.XPathExpressionException;
@@ -60,7 +64,7 @@ import java.util.Map;
  * @version $Id:$
  */
 public class TestHarness {
-
+  protected CoreContainer container;
   private SolrCore core;
   private XPath xpath = XPathFactory.newInstance().newXPath();
   private DocumentBuilder builder;
@@ -123,8 +127,19 @@ public class TestHarness {
   public TestHarness( String dataDirectory,
                       SolrConfig solrConfig,
                       IndexSchema indexSchema) {
+      this("", new Initializer("", dataDirectory, solrConfig, indexSchema));
+  }
+  
+  public TestHarness(String coreName, CoreContainer.Initializer init) {
     try {
-      core = new SolrCore( null, dataDirectory, solrConfig, indexSchema, null);
+      container = init.initialize();
+      if (coreName == null)
+        coreName = "";
+      // get the core & decrease its refcount:
+      // the container holds the core for the harness lifetime
+      core = container.getCore(coreName);
+      if (core != null)
+        core.close();
       builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
       
       updater = new XmlUpdateRequestHandler();
@@ -133,6 +148,42 @@ public class TestHarness {
       throw new RuntimeException(e);
     }
   }
+  
+  // Creates a container based on infos needed to create one core
+  static class Initializer extends CoreContainer.Initializer {
+    String coreName;
+    String dataDirectory;
+    SolrConfig solrConfig;
+    IndexSchema indexSchema;
+    public Initializer(String coreName,
+                      String dataDirectory,
+                      SolrConfig solrConfig,
+                      IndexSchema indexSchema) {
+      if (coreName == null)
+        coreName = "";
+      this.coreName = coreName;
+      this.dataDirectory = dataDirectory;
+      this.solrConfig = solrConfig;
+      this.indexSchema = indexSchema;
+    }
+    public String getCoreName() {
+      return coreName;
+    }
+    @Override
+    public CoreContainer initialize() {
+      CoreContainer container = new CoreContainer(new SolrResourceLoader(SolrResourceLoader.locateInstanceDir()));
+      CoreDescriptor dcore = new CoreDescriptor(container, coreName, solrConfig.getResourceLoader().getInstanceDir());
+      dcore.setConfigName(solrConfig.getResourceName());
+      dcore.setSchemaName(indexSchema.getResourceName());
+      SolrCore core = new SolrCore( null, dataDirectory, solrConfig, indexSchema, dcore);
+      container.register(coreName, core, false);
+      return container;
+    }
+  }
+  
+  public CoreContainer getCoreContainer() {
+    return container;
+  }
 
   public SolrCore getCore() {
     return core;
@@ -152,9 +203,7 @@ public class TestHarness {
                 
     StringReader req = new StringReader(xml);
     StringWriter writer = new StringWriter(32000);
-    
+
-    // This relies on the fact that SolrCore.getSolrCore() uses the 
-    // last instantiated SolrCore.
     updater.doLegacyUpdate(req, writer);
     return writer.toString();
   }
@@ -321,7 +370,17 @@ public class TestHarness {
    * Shuts down and frees any resources
    */
   public void close() {
-    core.close();
+    if (container != null) {
+      for (SolrCore c : container.getCores()) {
+        if (c.getOpenCount() > 1)
+          throw new RuntimeException("SolrCore.getOpenCount()=="+core.getOpenCount());
+      }      
+    }
+
+    if (container != null) {
+      container.shutdown();
+      container = null;
+    }
   }
 
   /**

src/test/org/apache/solr/core/SolrCoreTest.java

@@ -24,13 +24,14 @@ import org.apache.solr.request.SolrRequestHandler;
 import org.apache.solr.util.AbstractSolrTestCase;
 import org.apache.solr.util.plugin.SolrCoreAware;
 
+import java.util.concurrent.*;
+import java.util.*;
 public class SolrCoreTest extends AbstractSolrTestCase {
 
   public String getSchemaFile() { return "schema.xml"; }
   public String getSolrConfigFile() { return "solrconfig.xml"; }
-
+  
   public void testRequestHandlerRegistry() {
-    // property values defined in build.xml
     SolrCore core = h.getCore();
 
     EmptyRequestHandler handler1 = new EmptyRequestHandler();
@@ -46,7 +47,8 @@ public class SolrCoreTest extends AbstractSolrTestCase {
   }
 
   public void testClose() throws Exception {
-    SolrCore core = h.getCore();
+    final CoreContainer cores = h.getCoreContainer();
+    SolrCore core = cores.getCore("");
 
     ClosingRequestHandler handler1 = new ClosingRequestHandler();
     handler1.inform( core );
@@ -56,10 +58,116 @@ public class SolrCoreTest extends AbstractSolrTestCase {
     assertNull( old ); // should not be anything...
     assertEquals( core.getRequestHandlers().get( path ), handler1 );
     core.close();
+    cores.shutdown();
     assertTrue("Handler not closed", handler1.closed == true);
   }
+  
+  public void testRefCount() throws Exception {
+    SolrCore core = h.getCore();
+    assertTrue("Refcount != 1", core.getOpenCount() == 1);
+    
+    final CoreContainer cores = h.getCoreContainer();
+    SolrCore c1 = cores.getCore("");
+    assertTrue("Refcount != 2", core.getOpenCount() == 2);
+
+    ClosingRequestHandler handler1 = new ClosingRequestHandler();
+    handler1.inform( core );
+
+    String path = "/this/is A path /that won't be registered!";
+    SolrRequestHandler old = core.registerRequestHandler( path, handler1 );
+    assertNull( old ); // should not be anything...
+    assertEquals( core.getRequestHandlers().get( path ), handler1 );
+   
+    SolrCore c2 = cores.getCore("");
+    c1.close();
+    assertTrue("Refcount < 1", core.getOpenCount() >= 1);
+    assertTrue("Handler is closed", handler1.closed == false);
+    
+    c1 = cores.getCore("");
+    assertTrue("Refcount < 2", core.getOpenCount() >= 2);
+    assertTrue("Handler is closed", handler1.closed == false);
+    
+    c2.close();
+    assertTrue("Refcount < 1", core.getOpenCount() >= 1);
+    assertTrue("Handler is closed", handler1.closed == false);
+
+    c1.close();
+    cores.shutdown();
+    assertTrue("Refcount != 0", core.getOpenCount() == 0);
+    assertTrue("Handler not closed", core.isClosed() && handler1.closed == true);
+  }
+    
+
+  public void testRefCountMT() throws Exception {
+    SolrCore core = h.getCore();
+    assertTrue("Refcount != 1", core.getOpenCount() == 1);
+
+    final ClosingRequestHandler handler1 = new ClosingRequestHandler();
+    handler1.inform(core);
+    String path = "/this/is A path /that won't be registered!";
+    SolrRequestHandler old = core.registerRequestHandler(path, handler1);
+    assertNull(old); // should not be anything...
+    assertEquals(core.getRequestHandlers().get(path), handler1);
+
+    final int LOOP = 100;
+    final int MT = 16;
+    ExecutorService service = Executors.newFixedThreadPool(MT);
+    List<Callable<Integer>> callees = new ArrayList<Callable<Integer>>(MT);
+    final CoreContainer cores = h.getCoreContainer();
+    for (int i = 0; i < MT; ++i) {
+      Callable<Integer> call = new Callable<Integer>() {
+        void yield(int n) {
+          try {
+            Thread.sleep(0, (n % 13 + 1) * 10);
+          } catch (InterruptedException xint) {
+          }
+        }
+        
+        public Integer call() {
+          SolrCore core = null;
+          int r = 0;
+          try {
+            for (int l = 0; l < LOOP; ++l) {
+              r += 1;
+              core = cores.getCore("");
+              // sprinkle concurrency hinting...
+              yield(l);
+              assertTrue("Refcount < 1", core.getOpenCount() >= 1);              
+              yield(l);
+              assertTrue("Refcount > 17", core.getOpenCount() <= 17);             
+              yield(l);
+              assertTrue("Handler is closed", handler1.closed == false);
+              yield(l);
+              core.close();
+              core = null;
+              yield(l);
+            }
+            return r;
+          } finally {
+            if (core != null)
+              core.close();
+          }
+        }
+      };
+      callees.add(call);
+    }
+
+    List<Future<Integer>> results = service.invokeAll(callees);
+    for (Future<Integer> result : results) {
+      assertTrue("loop=" + result.get() +" < " + LOOP, result.get() >= LOOP);
+    }
+    
+    cores.shutdown();
+    assertTrue("Refcount != 0", core.getOpenCount() == 0);
+    assertTrue("Handler not closed", core.isClosed() && handler1.closed == true);
+    
+    service.shutdown();
+    assertTrue("Running for too long...", service.awaitTermination(60, TimeUnit.SECONDS));
+  }
 }
 
+
+
 class ClosingRequestHandler extends EmptyRequestHandler implements SolrCoreAware {
   boolean closed = false;
 

src/webapp/src/org/apache/solr/servlet/SolrDispatchFilter.java

@@ -285,6 +285,9 @@ public class SolrDispatchFilter implements Filter
         if( solrReq != null ) {
           solrReq.close();
         }
+        if (core != null) {
+          core.close();
+        }
       }
     }
 

src/webapp/web/admin/index.jsp

@@ -21,6 +21,8 @@
 <%-- $Name:  $ --%>
 
 <%@ page import="java.util.Date" %>
+<%@ page import="java.util.List" %>
+<%@ page import="java.util.Collection" %>
 
 <%-- jsp:include page="header.jsp"/ --%>
 <%-- do a verbatim include so we can use the local vars --%>
@@ -52,15 +54,12 @@
 </tr>
 
 <%-- List the cores (that arent this one) so we can switch --%>
-<% org.apache.solr.core.CoreContainer multicore = (org.apache.solr.core.CoreContainer)request.getAttribute("org.apache.solr.CoreContainer");
+<% org.apache.solr.core.CoreContainer cores = (org.apache.solr.core.CoreContainer)request.getAttribute("org.apache.solr.CoreContainer");
-  if (multicore!=null) {
+  if (cores!=null) {
-  java.util.Collection<SolrCore> cores = multicore.getCores();
+    Collection<String> names = cores.getCoreNames();
-if (cores.size() > 1) {%><tr><td><strong>Cores:</strong><br></td><td><%
+    if (names.size() > 1) {%><tr><td><strong>Cores:</strong><br></td><td><%
-  java.util.Iterator<SolrCore> icore = cores.iterator();
+    for (String name : names) {
-  while (icore.hasNext()) {
+    %>[<a href="../../<%=name%>/admin/"><%=name%></a>]<%         
-    SolrCore acore = icore.next();
-    if (acore == core) continue;
-    %>[<a href="../../<%=acore.getName()%>/admin/"><%=acore.getName()%></a>]<%         
   }%></td></tr><%
 }}%>