BaseRepositoryConnector.java

/* $Id: BaseRepositoryConnector.java 996524 2010-09-13 13:38:01Z kwright $ */

/**
* 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.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.manifoldcf.crawler.connectors;

import org.apache.manifoldcf.core.interfaces.*;
import org.apache.manifoldcf.agents.interfaces.*;
import org.apache.manifoldcf.crawler.interfaces.*;

import java.io.*;
import java.util.*;

/** This base class describes an instance of a connection between a repository and ManifoldCF's
* standard "pull" ingestion agent.
*
* Each instance of this interface is used in only one thread at a time.  Connection Pooling
* on these kinds of objects is performed by the factory which instantiates repository connectors
* from symbolic names and config parameters, and is pooled by these parameters.  That is, a pooled connector
* handle is used only if all the connection parameters for the handle match.
*
* Implementers of this interface should provide a default constructor which has this signature:
*
* xxx();
*
* Connectors are either configured or not.  If configured, they will persist in a pool, and be
* reused multiple times.  Certain methods of a connector may be called before the connector is
* configured.  This includes basically all methods that permit inspection of the connector's
* capabilities.  The complete list is:
*
*
* The purpose of the repository connector is to allow documents to be fetched from the repository.
*
* Each repository connector describes a set of documents that are known only to that connector.
* It therefore establishes a space of document identifiers.  Each connector will only ever be
* asked to deal with identifiers that have in some way originated from the connector.
*
* Documents are fetched using processDocuments(), which then gets to decide how to dispose of the
* document using the methods available by means of the provided IProcessActivity object.
*/
public abstract class BaseRepositoryConnector extends org.apache.manifoldcf.core.connector.BaseConnector implements IRepositoryConnector
{
  public static final String _rcsid = "@(#)$Id: BaseRepositoryConnector.java 996524 2010-09-13 13:38:01Z kwright $";

  /** Tell the world what model this connector uses for getDocumentIdentifiers().
  * This must return a model value as specified above.
  *@return the model type value.
  */
  @Override
  public int getConnectorModel()
  {
    // Return the simplest model - full everything
    return MODEL_ALL;
  }

  /** Return the list of activities that this connector supports (i.e. writes into the log).
  *@return the list.
  */
  @Override
  public String[] getActivitiesList()
  {
    return new String[0];
  }

  /** Return the list of relationship types that this connector recognizes.
  *@return the list.
  */
  @Override
  public String[] getRelationshipTypes()
  {
    // The base situation is that there are no relationships.
    return new String[0];
  }

  /** Get the bin name strings for a document identifier.  The bin name describes the queue to which the
  * document will be assigned for throttling purposes.  Throttling controls the rate at which items in a
  * given queue are fetched; it does not say anything about the overall fetch rate, which may operate on
  * multiple queues or bins.
  * For example, if you implement a web crawler, a good choice of bin name would be the server name, since
  * that is likely to correspond to a real resource that will need real throttle protection.
  *@param documentIdentifier is the document identifier.
  *@return the set of bin names.  If an empty array is returned, it is equivalent to there being no request
  * rate throttling available for this identifier.
  */
  @Override
  public String[] getBinNames(String documentIdentifier)
  {
    // Base version has one bin for all documents.  Use empty string for this since "*" would make
    // regexps be difficult to write.
    return new String[]{""};
  }

  /** Request arbitrary connector information.
  * This method is called directly from the API in order to allow API users to perform any one of several connector-specific
  * queries.
  *@param output is the response object, to be filled in by this method.
  *@param command is the command, which is taken directly from the API request.
  *@return true if the resource is found, false if not.  In either case, output may be filled in.
  */
  @Override
  public boolean requestInfo(Configuration output, String command)
    throws ManifoldCFException
  {
    return false;
  }

  /** Queue "seed" documents.  Seed documents are the starting places for crawling activity.  Documents
  * are seeded when this method calls appropriate methods in the passed in ISeedingActivity object.
  *
  * This method can choose to find repository changes that happen only during the specified time interval.
  * The seeds recorded by this method will be viewed by the framework based on what the
  * getConnectorModel() method returns.
  *
  * It is not a big problem if the connector chooses to create more seeds than are
  * strictly necessary; it is merely a question of overall work required.
  *
  * The end time and seeding version string passed to this method may be interpreted for greatest efficiency.
  * For continuous crawling jobs, this method will
  * be called once, when the job starts, and at various periodic intervals as the job executes.
  *
  * When a job's specification is changed, the framework automatically resets the seeding version string to null.  The
  * seeding version string may also be set to null on each job run, depending on the connector model returned by
  * getConnectorModel().
  *
  * Note that it is always ok to send MORE documents rather than less to this method.
  * The connector will be connected before this method can be called.
  *@param activities is the interface this method should use to perform whatever framework actions are desired.
  *@param spec is a document specification (that comes from the job).
  *@param seedTime is the end of the time range of documents to consider, exclusive.
  *@param lastSeedVersionString is the last seeding version string for this job, or null if the job has no previous seeding version string.
  *@param jobMode is an integer describing how the job is being run, whether continuous or once-only.
  *@return an updated seeding version string, to be stored with the job.
  */
  @Override
  public String addSeedDocuments(ISeedingActivity activities, Specification spec,
    String lastSeedVersion, long seedTime, int jobMode)
    throws ManifoldCFException, ServiceInterruption
  {
    return "";
  }

  /** Process a set of documents.
  * This is the method that should cause each document to be fetched, processed, and the results either added
  * to the queue of documents for the current job, and/or entered into the incremental ingestion manager.
  * The document specification allows this class to filter what is done based on the job.
  * The connector will be connected before this method can be called.
  *@param documentIdentifiers is the set of document identifiers to process.
  *@param statuses are the currently-stored document versions for each document in the set of document identifiers
  * passed in above.
  *@param activities is the interface this method should use to queue up new document references
  * and ingest documents.
  *@param jobMode is an integer describing how the job is being run, whether continuous or once-only.
  *@param usesDefaultAuthority will be true only if the authority in use for these documents is the default one.
  */
  @Override
  public void processDocuments(String[] documentIdentifiers, IExistingVersions statuses, Specification spec,
    IProcessActivity activities, int jobMode, boolean usesDefaultAuthority)
    throws ManifoldCFException, ServiceInterruption
  {
    // Base implementation does nothing
  }

  /** Get the maximum number of documents to amalgamate together into one batch, for this connector.
  *@return the maximum number. 0 indicates "unlimited".
  */
  @Override
  public int getMaxDocumentRequest()
  {
    // Base implementation does one at a time.
    return 1;
  }

  // UI support methods.
  //
  // These support methods come in two varieties.  The first bunch is involved in setting up connection configuration information.  The second bunch
  // is involved in presenting and editing document specification information for a job.  The two kinds of methods are accordingly treated differently,
  // in that the first bunch cannot assume that the current connector object is connected, while the second bunch can.  That is why the first bunch
  // receives a thread context argument for all UI methods, while the second bunch does not need one (since it has already been applied via the connect()
  // method, above).

  /** Obtain the name of the form check javascript method to call.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  *@return the name of the form check javascript method.
  */
  @Override
  public String getFormCheckJavascriptMethodName(int connectionSequenceNumber)
  {
    return "s"+connectionSequenceNumber+"_checkSpecification";
    //return "checkSpecification";
  }

  /** Obtain the name of the form presave check javascript method to call.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  *@return the name of the form presave check javascript method.
  */
  @Override
  public String getFormPresaveCheckJavascriptMethodName(int connectionSequenceNumber)
  {
    return "s"+connectionSequenceNumber+"_checkSpecificationForSave";
    //return "checkSpecificationForSave";
  }

  /** Output the specification header section.
  * This method is called in the head section of a job page which has selected a repository connection of the
  * current type.  Its purpose is to add the required tabs to the list, and to output any javascript methods
  * that might be needed by the job editing HTML.
  * The connector will be connected before this method can be called.
  *@param out is the output to which any HTML should be sent.
  *@param locale is the locale the output is preferred to be in.
  *@param ds is the current document specification for this job.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  *@param tabsArray is an array of tab names.  Add to this array any tab names that are specific to the connector.
  */
  @Override
  public void outputSpecificationHeader(IHTTPOutput out, Locale locale, Specification ds,
    int connectionSequenceNumber, List<String> tabsArray)
    throws ManifoldCFException, IOException
  {
  }
  
  /** Output the specification body section.
  * This method is called in the body section of a job page which has selected a repository connection of the
  * current type.  Its purpose is to present the required form elements for editing.
  * The coder can presume that the HTML that is output from this configuration will be within appropriate
  *  <html>, <body>, and <form> tags.  The name of the form is always "editjob".
  * The connector will be connected before this method can be called.
  *@param out is the output to which any HTML should be sent.
  *@param locale is the locale the output is preferred to be in.
  *@param ds is the current document specification for this job.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  *@param actualSequenceNumber is the connection within the job that has currently been selected.
  *@param tabName is the current tab name.  (actualSequenceNumber, tabName) form a unique tuple within
  *  the job.
  */
  @Override
  public void outputSpecificationBody(IHTTPOutput out, Locale locale, Specification ds,
    int connectionSequenceNumber, int actualSequenceNumber, String tabName)
    throws ManifoldCFException, IOException
  {
  }

  /** Process a specification post.
  * This method is called at the start of job's edit or view page, whenever there is a possibility that form
  * data for a connection has been posted.  Its purpose is to gather form information and modify the
  * document specification accordingly.  The name of the posted form is always "editjob".
  * The connector will be connected before this method can be called.
  *@param variableContext contains the post data, including binary file-upload information.
  *@param locale is the locale the output is preferred to be in.
  *@param ds is the current document specification for this job.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  *@return null if all is well, or a string error message if there is an error that should prevent saving of
  * the job (and cause a redirection to an error page).
  */
  @Override
  public String processSpecificationPost(IPostParameters variableContext, Locale locale, Specification ds,
    int connectionSequenceNumber)
    throws ManifoldCFException
  {
    return null;
  }

  /** View specification.
  * This method is called in the body section of a job's view page.  Its purpose is to present the document
  * specification information to the user.  The coder can presume that the HTML that is output from
  * this configuration will be within appropriate <html> and <body> tags.
  * The connector will be connected before this method can be called.
  *@param out is the output to which any HTML should be sent.
  *@param locale is the locale the output is preferred to be in.
  *@param ds is the current document specification for this job.
  *@param connectionSequenceNumber is the unique number of this connection within the job.
  */
  @Override
  public void viewSpecification(IHTTPOutput out, Locale locale, Specification ds,
    int connectionSequenceNumber)
    throws ManifoldCFException, IOException
  {
  }

}