solr&lucene3.6.0源码解析（三）

solr索引操作（包括新增 更新 删除 提交 合并等）相关UML图如下

从上面的类图我们可以发现，其中体现了工厂方法模式及责任链模式的运用

UpdateRequestProcessor相当于责任链模式中的处理器角色，我们通过如下的对象图也许更能反映多个UpdateRequestProcessor类型的处理器的活动行为

UpdateRequestProcessorChain为请求处理器链，供客户端调用(内部依赖处理器工厂数组生成不同的处理器)

public final class UpdateRequestProcessorChain implements PluginInfoInitialized
{
  private UpdateRequestProcessorFactory[] chain;
  private final SolrCore solrCore;

  public UpdateRequestProcessorChain(SolrCore solrCore) {
    this.solrCore = solrCore;
  }

  public void init(PluginInfo info) {
    List<UpdateRequestProcessorFactory> list = solrCore.initPlugins(info.getChildren("processor"),UpdateRequestProcessorFactory.class,null);
    if(list.isEmpty()){
      throw new RuntimeException( "updateRequestProcessorChain require at least one processor");
    }
    chain = list.toArray(new UpdateRequestProcessorFactory[list.size()]); 
  }

  public UpdateRequestProcessorChain( UpdateRequestProcessorFactory[] chain , SolrCore solrCore) {
    this.chain = chain;
    this.solrCore =  solrCore;
  }

  public UpdateRequestProcessor createProcessor(SolrQueryRequest req, SolrQueryResponse rsp) 
  {
    UpdateRequestProcessor processor = null;
    UpdateRequestProcessor last = null;
    for (int i = chain.length-1; i>=0; i--) {
      processor = chain[i].getInstance(req, rsp, last);
      last = processor == null ? last : processor;
    }
    return last;
  }

  public UpdateRequestProcessorFactory[] getFactories() {
    return chain;
  }
}

UpdateRequestProcessorFactory为请求处理器抽象工厂类，用于实例化请求处理器（UpdateRequestProcessor），而具体的实例化过程延迟到子类实现

/**
 * A factory to generate an UpdateRequestProcessor for each request.  
 * 
 * If the factory needs access to {@link SolrCore} in initialization, it could 
 * implement {@link SolrCoreAware}
 * 
 * @since solr 1.3
 */
public abstract class UpdateRequestProcessorFactory implements NamedListInitializedPlugin
{    
  public void init( NamedList args )
  {
    // could process the Node
  }
  
  abstract public UpdateRequestProcessor getInstance( 
      SolrQueryRequest req, SolrQueryResponse rsp, UpdateRequestProcessor next );
}

请求处理器抽象类UpdateRequestProcessor，持有对自身类型的引用（责任链模式的体现）

/**
 * This is a good place for subclassed update handlers to process the document before it is 
 * indexed.  You may wish to add/remove fields or check if the requested user is allowed to 
 * update the given document...
 * 
 * Perhaps you continue adding an error message (without indexing the document)...
 * perhaps you throw an error and halt indexing (remove anything already indexed??)
 * 
 * By default, this just passes the request to the next processor in the chain.
 * 
 * @since solr 1.3
 */
public abstract class UpdateRequestProcessor {
  protected final Logger log = LoggerFactory.getLogger(getClass());

  protected final UpdateRequestProcessor next;

  public UpdateRequestProcessor( UpdateRequestProcessor next) {
    this.next = next;
  }

  public void processAdd(AddUpdateCommand cmd) throws IOException {
    if (next != null) next.processAdd(cmd);
  }

  public void processDelete(DeleteUpdateCommand cmd) throws IOException {
    if (next != null) next.processDelete(cmd);
  }

  public void processMergeIndexes(MergeIndexesCommand cmd) throws IOException {
    if (next != null) next.processMergeIndexes(cmd);
  }

  public void processCommit(CommitUpdateCommand cmd) throws IOException
  {
    if (next != null) next.processCommit(cmd);
  }

  /**
   * @since Solr 1.4
   */
  public void processRollback(RollbackUpdateCommand cmd) throws IOException
  {
    if (next != null) next.processRollback(cmd);
  }

  public void finish() throws IOException {
    if (next != null) next.finish();    
  }
}

具体工厂类RunUpdateProcessorFactory及具体请求处理器RunUpdateProcessor

/**
 * Pass the command to the UpdateHandler without any modifications
 * 
 * @since solr 1.3
 */
public class RunUpdateProcessorFactory extends UpdateRequestProcessorFactory 
{
  @Override
  public UpdateRequestProcessor getInstance(SolrQueryRequest req, SolrQueryResponse rsp, UpdateRequestProcessor next) 
  {
    return new RunUpdateProcessor(req, next);
  }
}

class RunUpdateProcessor extends UpdateRequestProcessor 
{
  private final SolrQueryRequest req;
  private final UpdateHandler updateHandler;

  public RunUpdateProcessor(SolrQueryRequest req, UpdateRequestProcessor next) {
    super( next );
    this.req = req;
    this.updateHandler = req.getCore().getUpdateHandler();
  }

  @Override
  public void processAdd(AddUpdateCommand cmd) throws IOException {
    cmd.doc = DocumentBuilder.toDocument(cmd.getSolrInputDocument(), req.getSchema());
    updateHandler.addDoc(cmd);
    super.processAdd(cmd);
  }

  @Override
  public void processDelete(DeleteUpdateCommand cmd) throws IOException {
    if( cmd.id != null ) {
      updateHandler.delete(cmd);
    }
    else {
      updateHandler.deleteByQuery(cmd);
    }
    super.processDelete(cmd);
  }

  @Override
  public void processMergeIndexes(MergeIndexesCommand cmd) throws IOException {
    updateHandler.mergeIndexes(cmd);
    super.processMergeIndexes(cmd);
  }

  @Override
  public void processCommit(CommitUpdateCommand cmd) throws IOException
  {
    updateHandler.commit(cmd);
    super.processCommit(cmd);
  }

  /**
   * @since Solr 1.4
   */
  @Override
  public void processRollback(RollbackUpdateCommand cmd) throws IOException
  {
    updateHandler.rollback(cmd);
    super.processRollback(cmd);
  }
}

命令参数

/** An index update command encapsulated in an object (Command pattern)
 *
 * @version $Id: UpdateCommand.java 1065312 2011-01-30 16:08:25Z rmuir $
 */
  public class UpdateCommand {
    protected String commandName;

    public UpdateCommand(String commandName) {
      this.commandName = commandName;
    }

    @Override
    public String toString() {
      return commandName;
    }
  }

AddUpdateCommand命令

/**
 * @version $Id: AddUpdateCommand.java 1145201 2011-07-11 15:18:47Z yonik $
 */
public class AddUpdateCommand extends UpdateCommand {
   // optional id in "internal" indexed form... if it is needed and not supplied,
   // it will be obtained from the doc.
   public String indexedId;

   // The Lucene document to be indexed
   public Document doc;

   // Higher level SolrInputDocument, normally used to construct the Lucene Document
   // to index.
   public SolrInputDocument solrDoc;

   public boolean allowDups;
   public boolean overwritePending;
   public boolean overwriteCommitted;
   
   public Term updateTerm;
   public int commitWithin = -1;
   

   /** Reset state to reuse this object with a different document in the same request */
   public void clear() {
     doc = null;
     solrDoc = null;
     indexedId = null;
   }

   public SolrInputDocument getSolrInputDocument() {
     return solrDoc;
   }

   public Document getLuceneDocument(IndexSchema schema) {
     if (doc == null && solrDoc != null) {
       // TODO??  build the doc from the SolrDocument?
     }
     return doc;    
   }

   public String getIndexedId(IndexSchema schema) {
     if (indexedId == null) {
       SchemaField sf = schema.getUniqueKeyField();
       if (sf != null) {
         if (doc != null) {
           schema.getUniqueKeyField();
           Fieldable storedId = doc.getFieldable(sf.getName());
           indexedId = sf.getType().storedToIndexed(storedId);
         }
         if (solrDoc != null) {
           SolrInputField field = solrDoc.getField(sf.getName());
           if (field != null) {
             indexedId = sf.getType().toInternal( field.getFirstValue().toString() );
           }
         }
       }
     }
     return indexedId;
   }

   public String getPrintableId(IndexSchema schema) {
     SchemaField sf = schema.getUniqueKeyField();
     if (indexedId != null && sf != null) {
       return sf.getType().indexedToReadable(indexedId);
     }

     if (doc != null) {
       return schema.printableUniqueKey(doc);
     }

     if (solrDoc != null && sf != null) {
       SolrInputField field = solrDoc.getField(sf.getName());
       if (field != null) {
         return field.getFirstValue().toString();
       }
     }
     return "(null)";
   }

   public AddUpdateCommand() {
     super("add");
   }

   @Override
  public String toString() {
     StringBuilder sb = new StringBuilder(commandName);
     sb.append(':');
     if (indexedId !=null) sb.append("id=").append(indexedId);
     sb.append(",allowDups=").append(allowDups);
     sb.append(",overwritePending=").append(overwritePending);
     sb.append(",overwriteCommitted=").append(overwriteCommitted);
     return sb.toString();
   }
 }

DeleteUpdateCommand命令

/**
 * @version $Id: DeleteUpdateCommand.java 1235304 2012-01-24 15:39:17Z janhoy $
 */
public class DeleteUpdateCommand extends UpdateCommand {
  public String id;    // external (printable) id, for delete-by-id
  public String query; // query string for delete-by-query
  public boolean fromPending;
  public boolean fromCommitted;
  public int commitWithin = -1;

  public DeleteUpdateCommand() {
    super("delete");
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder(commandName);
    sb.append(':');
    if (id!=null) sb.append("id=").append(id);
    else sb.append("query=`").append(query).append('`');
    sb.append(",fromPending=").append(fromPending);
    sb.append(",fromCommitted=").append(fromCommitted);
    sb.append(",commitWithin=").append(commitWithin);
    return sb.toString();
  }
}

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