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    1   /* BeanShellProcessor
    2    *
    3    * Created on Aug 4, 2006
    4    *
    5    * Copyright (C) 2006 Internet Archive.
    6    *
    7    * This file is part of the Heritrix web crawler (crawler.archive.org).
    8    *
    9    * Heritrix is free software; you can redistribute it and/or modify
    10   * it under the terms of the GNU Lesser Public License as published by
    11   * the Free Software Foundation; either version 2.1 of the License, or
    12   * any later version.
    13   *
    14   * Heritrix is distributed in the hope that it will be useful,
    15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
    16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    17   * GNU Lesser Public License for more details.
    18   *
    19   * You should have received a copy of the GNU Lesser Public License
    20   * along with Heritrix; if not, write to the Free Software
    21   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
    22   */
    23  package org.archive.crawler.processor;
    24
    25  import java.io.File;
    26  import java.io.IOException;
    27  import java.util.Collections;
    28  import java.util.HashMap;
    29  import java.util.Map;
    30  import java.util.logging.Level;
    31  import java.util.logging.Logger;
    32
    33  import org.archive.crawler.datamodel.CrawlURI;
    34  import org.archive.crawler.datamodel.FetchStatusCodes;
    35  import org.archive.crawler.framework.Processor;
    36  import org.archive.crawler.settings.SimpleType;
    37  import org.archive.crawler.settings.Type;
    38
    39  import bsh.EvalError;
    40  import bsh.Interpreter;
    41
    42  /***
    43   * A processor which runs a BeanShell script on the CrawlURI.
    44   *
    45   * Script source may be provided via a file
    46   * local to the crawler.
    47   * Script source should define
    48   * a method with one argument, 'run(curi)'. Each processed CrawlURI is
    49   * passed to this script method.
    50   *
    51   * Other variables available to the script include 'self' (this
    52   * BeanShellProcessor instance) and 'controller' (the crawl's
    53   * CrawlController instance).
    54   *
    55   * @author gojomo
    56   * @version $Date: 2006-09-25 20:19:54 +0000 (Mon, 25 Sep 2006) $, $Revision: 4654 $
    57   */
    58  public class BeanShellProcessor extends Processor implements FetchStatusCodes {
    59
    60      private static final long serialVersionUID = 6926589944337050754L;
    61
    62      private static final Logger logger =
    63          Logger.getLogger(BeanShellProcessor.class.getName());
    64
    65      /*** setting for script file */
    66      public final static String ATTR_SCRIPT_FILE = "script-file";
    67
    68      /*** whether each thread should have its own script runner (true), or
    69       * they should share a single script runner with synchronized access */
    70      public final static String ATTR_ISOLATE_THREADS = "isolate-threads";
    71
    72      protected ThreadLocal<Interpreter> threadInterpreter;
    73      protected Interpreter sharedInterpreter;
    74      public Map<Object,Object> sharedMap = Collections.synchronizedMap(
    75              new HashMap<Object,Object>());
    76
    77      /***
    78       * Constructor.
    79       * @param name Name of this processor.
    80       */
    81      public BeanShellProcessor(String name) {
    82          super(name, "BeanShellProcessor. Runs the BeanShell script source " +
    83                  "(supplied directly or via a file path) against the " +
    84                  "current URI. Source should define a script method " +
    85                  "'process(curi)' which will be passed the current CrawlURI. " +
    86                  "The script may also access this BeanShellProcessor via" +
    87                  "the 'self' variable and the CrawlController via the " +
    88                  "'controller' variable.");
    89          Type t = addElementToDefinition(new SimpleType(ATTR_SCRIPT_FILE,
    90                  "BeanShell script file", ""));
    91          t.setOverrideable(false);
    92          t = addElementToDefinition(new SimpleType(ATTR_ISOLATE_THREADS,
    93                  "Whether each ToeThread should get its own independent " +
    94                  "script context, or they should share synchronized access " +
    95                  "to one context. Default is true, meaning each threads " +
    96                  "gets its own isolated context.", true));
    97          t.setOverrideable(false);
    98
    99      }
    100
    101     protected synchronized void innerProcess(CrawlURI curi) {
    102         // depending on previous configuration, interpreter may
    103         // be local to this thread or shared
    104         Interpreter interpreter = getInterpreter();
    105         synchronized(interpreter) {
    106             // synchronization is harmless for local thread interpreter,
    107             // necessary for shared interpreter
    108             try {
    109                 interpreter.set("curi",curi);
    110                 interpreter.eval("process(curi)");
    111             } catch (EvalError e) {
    112                 // TODO Auto-generated catch block
    113                 e.printStackTrace();
    114             }
    115         }
    116     }
    117
    118     /***
    119      * Get the proper Interpreter instance -- either shared or local
    120      * to this thread.
    121      * @return Interpreter to use
    122      */
    123     protected Interpreter getInterpreter() {
    124         if(sharedInterpreter!=null) {
    125             return sharedInterpreter;
    126         }
    127         Interpreter interpreter = threadInterpreter.get();
    128         if(interpreter==null) {
    129             interpreter = newInterpreter();
    130             threadInterpreter.set(interpreter);
    131         }
    132         return interpreter;
    133     }
    134
    135     /***
    136      * Create a new Interpreter instance, preloaded with any supplied
    137      * source code or source file and the variables 'self' (this
    138      * BeanShellProcessor) and 'controller' (the CrawlController).
    139      *
    140      * @return  the new Interpreter instance
    141      */
    142     protected Interpreter newInterpreter() {
    143         Interpreter interpreter = new Interpreter();
    144         try {
    145             interpreter.set("self", this);
    146             interpreter.set("controller", getController());
    147
    148             String filePath = (String) getUncheckedAttribute(null, ATTR_SCRIPT_FILE);
    149             if(filePath.length()>0) {
    150                 try {
    151                     File file = getSettingsHandler().getPathRelativeToWorkingDirectory(filePath);
    152                     interpreter.source(file.getPath());
    153                 } catch (IOException e) {
    154                     logger.log(Level.SEVERE,"unable to read script file",e);
    155                 }
    156             }
    157         } catch (EvalError e) {
    158             // TODO Auto-generated catch block
    159             e.printStackTrace();
    160         }
    161
    162         return interpreter;
    163     }
    164
    165     protected void initialTasks() {
    166         super.initialTasks();
    167         kickUpdate();
    168     }
    169
    170     /***
    171      * Setup (or reset) Intepreter variables, as appropraite based on
    172      * thread-isolation setting.
    173      */
    174     public void kickUpdate() {
    175         // TODO make it so running state (tallies, etc.) isn't lost on changes
    176         // unless unavoidable
    177         if((Boolean)getUncheckedAttribute(null,ATTR_ISOLATE_THREADS)) {
    178             sharedInterpreter = null;
    179             threadInterpreter = new ThreadLocal<Interpreter>();
    180         } else {
    181             sharedInterpreter = newInterpreter();
    182             threadInterpreter = null;
    183         }
    184     }
    185 }