torquedatadumptask.java

一个数据访问层Torque3.1的生成器的源代码

package org.apache.torque.task;

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 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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import java.util.Iterator;
import java.util.NoSuchElementException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import org.apache.tools.ant.Project;
import org.apache.velocity.context.Context;

import com.workingdogs.village.QueryDataSet;
import com.workingdogs.village.Record;

/**
 * An extended Texen task used for dumping data from db into XML
 *
 * @author <a href="mailto:[e-mail]">Fedor Karpelevitch</a>
 * @author <a href="[e-mail]">Jason van Zyl</a>
 * @author <a href="[e-mail]">Daniel Rall</a>
 * @version $Id: TorqueDataDumpTask.java,v 1.3 2003/07/25 16:47:42 henning Exp $
 */
public class TorqueDataDumpTask extends TorqueDataModelTask
{
    /**
     * Database name.
     */
    private String databaseName;

    /**
     * Database URL used for JDBC connection.
     */
    private String databaseUrl;

    /**
     * Database driver used for JDBC connection.
     */
    private String databaseDriver;

    /**
     * Database user used for JDBC connection.
     */
    private String databaseUser;

    /**
     * Database password used for JDBC connection.
     */
    private String databasePassword;

    /**
     * The database connection used to retrieve the data to dump.
     */
    private Connection conn;

    /**
     * The statement used to acquire the data to dump.
     */
    private Statement stmt;

    /**
     * Get the database name to dump
     *
     * @return  The DatabaseName value
     */
    public String getDatabaseName()
    {
        return databaseName;
    }

    /**
     * Set the database name
     *
     * @param  v The new DatabaseName value
     */
    public void setDatabaseName(String v)
    {
        databaseName = v;
    }

    /**
     * Get the database url
     *
     * @return  The DatabaseUrl value
     */
    public String getDatabaseUrl()
    {
        return databaseUrl;
    }

    /**
     * Set the database url
     *
     * @param  v The new DatabaseUrl value
     */
    public void setDatabaseUrl(String v)
    {
        databaseUrl = v;
    }

    /**
     * Get the database driver name
     *
     * @return  String database driver name
     */
    public String getDatabaseDriver()
    {
        return databaseDriver;
    }

    /**
     * Set the database driver name
     *
     * @param  v The new DatabaseDriver value
     */
    public void setDatabaseDriver(String v)
    {
        databaseDriver = v;
    }

    /**
     * Get the database user
     *
     * @return  String database user
     */
    public String getDatabaseUser()
    {
        return databaseUser;
    }

    /**
     * Set the database user
     *
     * @param  v The new DatabaseUser value
     */
    public void setDatabaseUser(String v)
    {
        databaseUser = v;
    }

    /**
     * Get the database password
     *
     * @return  String database password
     */
    public String getDatabasePassword()
    {
        return databasePassword;
    }

    /**
     * Set the database password
     *
     * @param  v The new DatabasePassword value
     */
    public void setDatabasePassword(String v)
    {
        databasePassword = v;
    }

    /**
     * Initializes initial context
     *
     * @return the context
     * @throws Exception generic exception
     */
    public Context initControlContext() throws Exception
    {
        super.initControlContext();

        context.put("dataset", "all");

        log("Torque - TorqueDataDump starting");
        log("Your DB settings are:");
        log("driver: " + databaseDriver);
        log("URL: " + databaseUrl);
        log("user: " + databaseUser);
        // log("password: " + databasePassword);

        try
        {
            Class.forName(databaseDriver);
            log("DB driver instantiated sucessfully", Project.MSG_DEBUG);

            conn = DriverManager.getConnection(
                    databaseUrl, databaseUser, databasePassword);

            log("DB connection established", Project.MSG_DEBUG);
            context.put("tableTool", new TableTool());
        }
        catch (SQLException se)
        {
            System.err.println("SQLException while connecting to DB:");
            se.printStackTrace();
        }
        catch (ClassNotFoundException cnfe)
        {
            System.err.println("cannot load driver:");
            cnfe.printStackTrace();
        }
        context.put("escape", new org.apache.velocity.anakia.Escape());
        return context;
    }

    /**
     * Closes the db-connection, overriding the <code>cleanup()</code> hook
     * method in <code>TexenTask</code>.
     *
     * @throws Exception Database problem while closing resource.
     */
    protected void cleanup() throws Exception
    {
        if (stmt != null)
        {
            stmt.close();
        }

        if (conn != null)
        {
            conn.close();
        }
    }

    /**
     *  A nasty do-it-all tool class. It serves as:
     *  <ul>
     *  <li>context tool to fetch a table iterator</li>
     *  <li>the abovenamed iterator which iterates over the table</li>
     *  <li>getter for the table fields</li>
     *  </ul>
     *
     * @author  fedor
     */
    public class TableTool implements Iterator
    {
        /** querydataset */
        private QueryDataSet qds;
        /** is empty */
        private boolean isEmpty;
        /** current index */
        private int curIndex = -1;
        /** current record */
        private Record curRec = null;

        /**
         *  Constructor for the TableTool object
         */
        public TableTool()
        {
        }

        /**
         * Constructor for the TableTool object
         *
         * @param qds Description of Parameter
         * @throws Exception Problem using database record set cursor.
         */
        protected TableTool(QueryDataSet qds) throws Exception
        {
            this.qds = qds;
            this.qds.fetchRecords();
            this.isEmpty = !(qds.size() > 0);
        }

        /**
         * Fetches an <code>Iterator</code> for the data in the named table.
         *
         * @param  tableName Description of Parameter
         * @return <code>Iterator</code> for the fetched data.
         * @throws Exception Problem creating connection or executing query.
         */
        public TableTool fetch(String tableName) throws Exception
        {
            log("Fetching data for table " + tableName, Project.MSG_INFO);
            // Set Statement object in associated TorqueDataDump
            // instance
            return new TableTool
                (new QueryDataSet(conn, "SELECT * FROM " + tableName));
        }

        /**
         * check if there are more records in the QueryDataSet
         *
         * @return true if there are more records
         */
        public boolean hasNext()
        {
            try
            {
                return ((this.curIndex < this.qds.size() - 1) && (!isEmpty));
            }
            catch (Exception se)
            {
                System.err.println("Exception :");
                se.printStackTrace();
            }
            return false;
        }

        /**
         * load the next record from the QueryDataSet
         *
         * @return Description of the Returned Value
         * @throws NoSuchElementException Description of Exception
         */
        public Object next() throws NoSuchElementException
        {
            try
            {
                System.err.print(".");
                this.curRec = this.qds.getRecord(++curIndex);
            }
            catch (Exception se)
            {
                System.err.println("Exception while iterating:");
                se.printStackTrace();
                throw new NoSuchElementException(se.getMessage());
            }
            return this;
        }

        /**
         * Returns the value for the column
         *
         * @param  columnName name of the column
         * @return  value of the column or null if it doesn't exist
         */
        public String get(String columnName)
        {
            try
            {
                return (this.curRec.getValue(columnName).asString());
            }
            catch (Exception se)
            {
                log("Exception fetching value " + columnName + ": "
                        + se.getMessage(), Project.MSG_ERR);
            }
            return null;
        }

        /**
         * unsupported! always throws Exception
         *
         * @throws UnsupportedOperationException unsupported
         */
        public void remove() throws UnsupportedOperationException
        {
            throw new UnsupportedOperationException();
        }
    }
}