source: trunk/greenstone3-extensions/gs3build/src/org/greenstone/gsdl3/gs3build/metadata/METSNamespace.java@ 12188

package org.greenstone.gsdl3.gs3build.metadata;

import java.io.PrintWriter;

import java.util.List;
import java.util.Iterator;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;

import org.greenstone.gsdl3.gs3build.database.*;

/**
 *  Implement a single namespace
 */

public abstract class METSNamespace
{
    protected String       type;        // the type of the metadata
    protected String       otherType;   // if a non-standard type, then...
    protected String       name;        // e.g. "DC" for Dublin Core
    protected METSLocation location;    // the location of the corresponding file
    protected String       group;       // the group of metadata namespaces to which
    // this namespace belongs
    protected String       id;          // the ID for this namespace

    public METSNamespace(String name)
    { 
    this.name        = name;
    this.location    = null;
    this.group       = null;
    this.id          = null;
    }
    
    public METSNamespace(String name, METSLocation location)
    { 
    this.location    = location;
    this.name        = name;
    this.group       = null;
    this.id          = null;
    }
    
    /**
     *  Get the name of the namespace...
     *
     *  @return <code>String</code> the name of the namespace
     */
    public String getName()
    { 
    return this.name;
    }
    
    /**
     *  Get the group of namespaces to which this namespace belongs.
     *
     *  @return <code>String</code> the name of the namespace group
     */
    public String getGroup()
    {
    return this.group;
    }
    
    /**
     *  Set the group of namespaces to which this namespace belongs.
     *
     *  @param <code>String</code> the name of the namespace group
     */
    public void setGroup(String group)
    { 
    this.group = group;
    }
    
    /**
     *  Get the ID for this namespace.
     *
     *  @return <code>String</code> the id of the namespace
     */
    public String getID()
    {
    return this.id;
    }
    
    /**
     *  Set the id of this namespace.
     *
     *  @param <code>String</code> the name of the namespace group
     */
    public void setID(String id)
    {
    this.id = id;
    }

    /**
     *  <p>Indicate whether this namespace is open to being changed or not.</p>
     *  <p>Metadata which is created from a distinct file cannot be changed,
     *  only those which have no associated file can be modified.
     *
     *  @return <code>boolean</code> whether this namespace can be altered.
     */
    public boolean isEditable()
    { 
    return (this.location == null);
    }
    
    public abstract boolean addMetadata(String label, String value);
    public abstract boolean setMetadata(String label, String value);
    public abstract boolean removeMetadata(String label);
    public abstract boolean removeMetadata(String label, String value);
    public abstract List    getMetadata(String label);
    public abstract Iterator getMetadataNames();
    public abstract boolean write(PrintWriter writer);
    //  public abstract boolean writeSQL(GS3SQLConnection connection);

    /**
     *  Write out the metadata to an SQL database through a <code>GS3SQLConnection</code>.
     *
     *  @param <code>int</code> the sql identifier of the parent object (in "metadata") table.
     *  @param <code>GS3SQLConnection</code> the SQL database to use.
     */
    public boolean writeSQL(int parentId, GS3SQLConnection connection)
    { 
    GS3SQLAction action;

    // If the namespace is not null, then set it...
    if (this.id != null) {
        // use an update action in this case...
        GS3SQLUpdate update = new GS3SQLUpdate("namespaces");
        update.addValue("NamespaceID", this.id);

        // set up the where clause
        GS3SQLWhere where = 
        new GS3SQLWhere(new GS3SQLWhereItem("NamespaceRef", "=", this.id, 
                            GS3SQLField.INTEGER_TYPE));
        update.setWhere(where);
        action = update;
    }
    else {
        GS3SQLInsert insert = new GS3SQLInsert("namespaces");
        action = insert;
    }

    if (this.location != null) {
        action.addValue("FileLoc", this.location.getLocation().toString());
        action.addValue("FileType", "URL");
    }
    else {
        // no location stuff
    }
    action.addValue("MetadataRef", Integer.toString(parentId), GS3SQLField.INTEGER_TYPE);
    action.addValue("NamespaceType", this.name);

    // Execute the action
    Statement statement = null;
    try {
        statement = connection.createStatement();
        statement.execute(action.toString());
    } catch (SQLException e) {
        System.err.println("METSNamespace.writeSQL(): "+e);
        return false;
    }
    // then get the namespace reference number if needsbe...
    if (this.id == null) {
        GS3SQLSelect select = new GS3SQLSelect("namespaces");
        select.addField("NamespaceRef");
        GS3SQLWhereItem whereItem = new GS3SQLWhereItem("MetadataRef", "=", Integer.toString(parentId), GS3SQLField.INTEGER_TYPE);
        GS3SQLWhere where = new GS3SQLWhere(whereItem);
        whereItem = new GS3SQLWhereItem("NamespaceType", "=", this.name);
        where.add(where);
        try {
        ResultSet result  = statement.executeQuery(select.toString());
            if (result.last()) {
            this.id = Integer.toString(result.getInt("NamespaceRef"));
        }
        statement.close();
        }
        catch (SQLException sqlex){
        this.id = null;
        System.err.println("METSNamespace.writeSQL(): "+sqlex);
        return false;
        }
    }
    
    return true;
    }
    
    public static METSNamespace readSQL(GS3SQLConnection connection, ResultSet resultSet)
    {
    METSLocation metsLocation = null;
    
    try {
        String name = resultSet.getString("NamespaceType");
        String id = resultSet.getString("NamespaceRef");
        String location = resultSet.getString("FileLoc");
        String type = resultSet.getString("FileType");
        if (location != null && type != null) {
        metsLocation = new METSLocation(type, location);
        }
        
        METSNamespace namespace = NamespaceFactory.initNamespace(name, metsLocation);
        namespace.id = id;

        int namespaceRef = resultSet.getInt("NamespaceRef");
      
        GS3SQLSelect select = new GS3SQLSelect("mdvalues");
        select.addField("*");
        GS3SQLWhere where = new GS3SQLWhere(new GS3SQLWhereItem("NamespaceRef", "=", Integer.toString(namespaceRef),
                                    GS3SQLField.INTEGER_TYPE));
        select.setWhere(where);

        Statement statement = connection.createStatement();
        ResultSet valuesSet = statement.executeQuery(select.toString());
        if (valuesSet.first()) {
        do {
            String label = valuesSet.getString("Label");
            String value = valuesSet.getString("Value");

            namespace.addMetadata(label, value);
        }
        while (valuesSet.next());
        }
        statement.close();
        return namespace;
    }
    catch (java.net.MalformedURLException urlEx){
        System.err.println("METSNamespace.readSQL(): "+urlEx);
    }
    catch (SQLException sqlEx){
        System.err.println("METSNamespace.readSQL(): "+sqlEx);
    }    
    return null;
    }
}