source: main/trunk/greenstone3/src/java/org/greenstone/gsdl3/util/SimpleCollectionDatabase.java@ 25635

/*
 *    SimpleCollectionDatabase.java
 *    Copyright (C) 2008 New Zealand Digital Library, http://www.nzdl.org
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package org.greenstone.gsdl3.util;

import java.util.Iterator;
import java.util.Set;
import java.util.Vector;

import org.apache.log4j.*;

import org.apache.commons.lang3.StringUtils;

public class SimpleCollectionDatabase implements OID.OIDTranslatable
{

    static Logger logger = Logger.getLogger(org.greenstone.gsdl3.util.SimpleCollectionDatabase.class.getName());

    /* just read access, many readers can share a database */
    public final static int READ = FlatDatabaseWrapper.READ;
    /* read/write, exclusive access */
    public final static int WRITE = FlatDatabaseWrapper.WRITE;

    protected FlatDatabaseWrapper coll_db = null;

    public SimpleCollectionDatabase(String db_type)
    {

        // Access databaseWrapper through reflection (forName) so code
        // can be more dynamic as to the database backends that are
        // supported for this installation of Greenstone

        String dbwrap_name = db_type.toUpperCase() + "Wrapper";
        Class dbwrap_class = null;

        try
        {
            String full_dbwrap_name = "org.greenstone.gsdl3.util." + dbwrap_name;
            dbwrap_class = Class.forName(full_dbwrap_name);
        }
        catch (ClassNotFoundException e)
        {
            try
            {
                //try the dbwrap_name alone in case the package name is
                //already specified
                dbwrap_class = Class.forName(dbwrap_name);
            }
            catch (ClassNotFoundException ae)
            {
                logger.error("Couldn't create SimpleCollectionDatabase of type " + db_type);
                logger.info(ae.getMessage());
            }
        }

        try
        {
            this.coll_db = (FlatDatabaseWrapper) dbwrap_class.newInstance();
        }
        catch (Exception e)
        {
            logger.error("Failed to call the constructor " + dbwrap_name + "()");
        }

    }

    public boolean databaseOK()
    {
        // Previously failed to open database
        // Most likely cause is that this installation of Greenstone3 has not 
        // been compiled with support for this database type
        return coll_db != null;
    }

    /**
     * open the database filename, with mode mode - uses the FlatDatabaseWrapper
     * modes
     */
    public boolean openDatabase(String filename, int mode)
    {
        return this.coll_db.openDatabase(filename, mode);
    }

    /** close the database */
    public void closeDatabase()
    {
        this.coll_db.closeDatabase();
    }

    /**
     * Returns a DBInfo structure of the key-value pairs associated with a
     * particular main key in the database
     */
    public DBInfo getInfo(String main_key)
    {
        //   logger.warn("All the entries of the db are:");
        //   this.coll_db.displayAllEntries();

        if (this.coll_db == null)
        {
            // Most likely cause is that this installation of Greenstone3 has not 
            // been compiled with support for this database type
            return null;
        }

        String key_info = this.coll_db.getValue(main_key);
        if (key_info == null || key_info.equals(""))
        {
            return null;
        }
        
        DBInfo info = new DBInfo();

        String[] lines = StringUtils.split(key_info, "\n");
        String key;
        String value;
        for (int i = 0; i < lines.length; i++)
        {
            logger.debug("line:" + lines[i]);
            int a = lines[i].indexOf('<');
            int b = lines[i].indexOf('>');
            if (a == -1 || b == -1)
            {
                logger.error("bad format in db");
            }
            else
            {
                key = lines[i].substring(a + 1, b);
                value = lines[i].substring(b + 1);
                logger.debug("key=" + key + ", val=" + value);
                info.addInfo(key, value);
            }
        }
        
        return info;
    }
    
    public boolean setInfo(String mainKey, DBInfo info)
    {
        StringBuilder valueToAdd = new StringBuilder();
        Iterator<String> i = info.getKeys().iterator();
        while (i.hasNext())
        {
            String currentKey = i.next();
            Vector<String> currentValues = (Vector<String>)info.getMultiInfo(currentKey);
            
            if(currentValues.size() == 0)
            {
                valueToAdd.append("<" + currentKey + ">\n");
                continue;
            }
            
            for(int j = 0; j < currentValues.size(); j++)
            {
                valueToAdd.append("<" + currentKey + ">" + currentValues.get(j) + "\n");
            }
        }
        
        //Remove the final \n
        if (valueToAdd.length() > 0)
        {
            valueToAdd.delete(valueToAdd.length() - 1, valueToAdd.length());
        }
        
        return this.coll_db.setValue(mainKey, valueToAdd.toString());
    }
    
    public String getValue(String key)
    {
        return this.coll_db.getValue(key);
    }
    
    public boolean setValue(String key, String value)
    {
        return this.coll_db.setValue(key, value);
    }
    
    public boolean deleteKey(String key)
    {
        return this.coll_db.deleteKey(key);
    }

    /** converts a greenstone OID to internal docnum */
    public String OID2Docnum(String OID)
    {
        DBInfo info = getInfo(OID);
        if (info != null)
        {
            return info.getInfo("docnum");
        }
        return null;
    }

    /**
     * converts a greenstone OID to an internal docnum, returning a Long -
     * convenience method
     */
    public long OID2DocnumLong(String OID)
    {
        DBInfo info = getInfo(OID);
        if (info != null)
        {
            long real_num = Long.parseLong(info.getInfo("docnum"));
            return real_num;
        }
        return -1;
    }

    /** converts a docnum to greenstone OID */
    public String docnum2OID(String docnum)
    {
        DBInfo info = getInfo(docnum);
        if (info != null)
        {
            String oid = info.getInfo("section");
            return oid;
        }
        else
        {
            return null;
        }
    }

    /**
     * converts a docnum to greenstone OID - convenience method
     */
    public String docnum2OID(long docnum)
    {
        return docnum2OID(Long.toString(docnum));
    }

    /** converts an external id to greenstone OID */
    public String externalId2OID(String extid)
    {
        DBInfo info = getInfo(extid);
        if (info != null)
        {
            String oid = info.getInfo("section");
            return oid;
        }
        return null;
    }

    /**
     * After OID.translateOID() is through, this method processes OID further to
     * translate relative oids into proper oids: .pr (parent), .rt (root) .fc
     * (first child), .lc (last child), .ns (next sibling), .ps (previous
     * sibling) .np (next page), .pp (previous page) : links sections in the
     * order that you'd read the document a suffix is expected to be present so
     * test before using
     */
    public String processOID(String doc_id, String top, String suff, int sibling_num)
    {
        DBInfo info = getInfo(doc_id);
        if (info == null)
        {
            logger.info("info is null!!");
            return top;
        }

        String contains = info.getInfo("contains");
        if (contains.equals(""))
        {
            // something is wrong
            return top;
        }
        contains = StringUtils.replace(contains, "\"", doc_id);
        String[] children = StringUtils.split(contains, ";");
        if (suff.equals("fc"))
        {
            return children[0];
        }
        else if (suff.equals("lc"))
        {
            return children[children.length - 1];
        }
        else
        {
            if (suff.equals("ss"))
            {
                return children[sibling_num - 1];
            }
            // find the position that we are at.
            int i = 0;
            while (i < children.length)
            {
                if (children[i].equals(top))
                {
                    break;
                }
                i++;
            }

            if (suff.equals("ns"))
            {
                if (i == children.length - 1)
                {
                    return children[i];
                }
                return children[i + 1];
            }
            else if (suff.equals("ps"))
            {
                if (i == 0)
                {
                    return children[i];
                }
                return children[i - 1];
            }
        }

        return top;
    }
}