LockMaster.java

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/*
 * Project: Server for annotations sharing
 * Author: Ing. Jaroslav Dytrych idytrych@fit.vutbr.cz
 * File: LockMaster.java
 * Description: Class manages documents locks
 */

/**
 * @file LockMaster.java
 *
 * @brief Class manages documents locks
 */

/**
 * @package cz.vutbr.fit.knot.annotations.comet.documentLock
 * 
 * @brief Classes responsible for synchronization of modifications of the document
 */
package cz.vutbr.fit.knot.annotations.comet.documentLock;

import java.util.ArrayList;
import java.util.Iterator;

/**
 * Class manages documents locks.
 *
 * @brief Class manages documents locks.
 * @author Martin Petr (xpetrm05)
 */
public class LockMaster {
  
  /** Array of created locks for suggestions */
  private ArrayList<Padlock> suggestionsLocks;
  
  /** Array of created locks for suggestions requests */
  private ArrayList<Padlock> suggReqLocks;
  
  /** Array of created locks for changes */
  private ArrayList<Padlock> changesDocLocks;
  
  /** Lock that locks sessions list for change */
  private Padlock sessionsLock; 

  /**
   * Constructor that inicialize locks arrays.
   */
  public LockMaster() {
    suggestionsLocks = new ArrayList<Padlock>();
    suggReqLocks = new ArrayList<Padlock>();
    changesDocLocks = new ArrayList<Padlock>();
    sessionsLock = null;
  }

  /**
   * The method creates a new lock, if the docuemnt id is found, method returns 
   * the appropriate lock.
   * 
   * @param docId Id of document for which lock is made available
   * @return new lock or appropriate lock
   */
  private synchronized Padlock makeSuggestionsPadlock(Integer docId){
    Iterator<Padlock> padIt = suggestionsLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    Padlock newPadlock = new Padlock(docId);
    suggestionsLocks.add(newPadlock);
    return newPadlock;
  }
  
  /**
   * Method which provides access to suggestions locks, when the lock for the 
   * document does not exist, method create it.
   * 
   * @param docId Id of document for which lock is made available
   * @return lock for suggestions for document with id in parameter
   */
  public synchronized Padlock getSuggestionLock(Integer docId){
    Iterator<Padlock> padIt = suggestionsLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    return makeSuggestionsPadlock(docId);
  }
  
  /**
   * The method creates a new lock, if the docuemnt id is found, method returns 
   * the appropriate lock.
   * 
   * @param docId Id of document for which lock is made available
   * @return new lock or appropriate lock
   */
  private synchronized Padlock makeSuggReqPadlock(Integer docId){
    Iterator<Padlock> padIt = suggReqLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    Padlock newPadlock = new Padlock(docId);
    suggReqLocks.add(newPadlock);
    return newPadlock;
  }
  
  /**
   * Method which provides access to suggestion request locks, when the lock for the 
   * document does not exist, method create it.
   * 
   * @param docId Id of document for which lock is made available
   * @return lock for suggestions requests for document with id in parameter
   */
  public synchronized Padlock getSuggReqLock(Integer docId){
    Iterator<Padlock> padIt = suggReqLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    return makeSuggReqPadlock(docId);
  }
  
  /**
   * The method creates a new lock, if the docuemnt id is found, method returns 
   * the appropriate lock.
   * 
   * @param docId Id of document for which lock is made available
   * @return new lock or appropriate lock
   */
  private synchronized Padlock makeDocumentPadlock(Integer docId){
    Iterator<Padlock> padIt = changesDocLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    Padlock newPadlock = new Padlock(docId);
    changesDocLocks.add(newPadlock);
    return newPadlock;
  }
  
  /**
   * Method which provides access to document locks, when the lock for the 
   * document does not exist, method create it.
   * 
   * @param docId Id of document for which lock is made available
   * @return lock for document for document with id in parameter
   */
  public synchronized Padlock getDocumentLock(Integer docId){
    Iterator<Padlock> padIt = changesDocLocks.iterator();
    while(padIt.hasNext()){
      Padlock currentPadlock = padIt.next();
      if(currentPadlock.getDocumentId().equals(docId)){
        return currentPadlock;
      }
    }
    
    return makeDocumentPadlock(docId);
  }
  
  
  /**
   * Method which provides access to dsessions lock, when the lock for the 
   * sessions does not exist, method create it.
   * 
   * @return lock for sessions for document with id in parameter
   */
  public Padlock getSessionsLock(){
    if(sessionsLock == null){
      sessionsLock = new Padlock(0);
    }
    return sessionsLock;
  }
}  // public class LockMaster