Package org.pentaho.reporting.engine.classic.extensions.datasources.scriptable

Source Code of org.pentaho.reporting.engine.classic.extensions.datasources.scriptable.ScriptableDataFactory

/*!
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* 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 Lesser General Public License for more details.
*
* Copyright (c) 2002-2013 Pentaho Corporation..  All rights reserved.
*/

package org.pentaho.reporting.engine.classic.extensions.datasources.scriptable;

import java.util.LinkedHashMap;
import javax.swing.table.TableModel;

import org.apache.bsf.BSFException;
import org.apache.bsf.BSFManager;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.AbstractDataFactory;
import org.pentaho.reporting.engine.classic.core.DataFactory;
import org.pentaho.reporting.engine.classic.core.DataRow;
import org.pentaho.reporting.engine.classic.core.ReportDataFactoryException;
import org.pentaho.reporting.engine.classic.core.ResourceBundleFactory;
import org.pentaho.reporting.engine.classic.core.states.LegacyDataRowWrapper;
import org.pentaho.reporting.libraries.base.config.Configuration;
import org.pentaho.reporting.libraries.resourceloader.ResourceKey;
import org.pentaho.reporting.libraries.resourceloader.ResourceManager;

/**
* A datafactory that uses a bean-scripting framework script to produce a tablemodel.
*
* @author Thomas Morgner
*/
public class ScriptableDataFactory extends AbstractDataFactory
{
  private static final Log logger = LogFactory.getLog(ScriptableDataFactory.class);
  private LinkedHashMap<String,String> queries;
  private String language;
  private transient BSFManager interpreter;
  private transient LegacyDataRowWrapper dataRowWrapper;
  private String script;
  private String shutdownScript;

  public ScriptableDataFactory()
  {
    queries = new LinkedHashMap<String,String>();
  }

  public String getLanguage()
  {
    return language;
  }

  public void setLanguage(final String language)
  {
    this.language = language;
  }

  public void setQuery(final String name, final String value)
  {
    if (value == null)
    {
      queries.remove(name);
    }
    else
    {
      queries.put(name, value);
    }
  }

  public String getScript()
  {
    return script;
  }

  public void setScript(final String script)
  {
    this.script = script;
  }

  public String getShutdownScript()
  {
    return shutdownScript;
  }

  public void setShutdownScript(final String shutdownScript)
  {
    this.shutdownScript = shutdownScript;
  }

  public String getQuery(final String name)
  {
    return queries.get(name);
  }

  public String[] getQueryNames()
  {
    return queries.keySet().toArray(new String[queries.size()]);
  }


  /**
   * Creates a new interpreter instance.
   *
   * @return the interpreter or null, if there was an error.
   */
  protected BSFManager createInterpreter() throws BSFException
  {
    final BSFManager interpreter = new BSFManager();
    initializeInterpreter(interpreter);
    return interpreter;
  }

  /**
   * Initializes the Bean-Scripting Framework manager.
   *
   * @param interpreter the BSF-Manager that should be initialized.
   * @throws BSFException if an error occured.
   */
  protected void initializeInterpreter(final BSFManager interpreter)
      throws BSFException
  {
    dataRowWrapper = new LegacyDataRowWrapper();
    interpreter.declareBean("dataRow", dataRowWrapper, DataRow.class); //$NON-NLS-1$
    interpreter.declareBean("configuration", getConfiguration(), Configuration.class); //$NON-NLS-1$
    interpreter.declareBean("contextKey", getContextKey(), ResourceKey.class); //$NON-NLS-1$
    interpreter.declareBean("resourceManager", getResourceManager(), ResourceManager.class); //$NON-NLS-1$
    interpreter.declareBean("resourceBundleFactory", getResourceBundleFactory(), ResourceBundleFactory.class); //$NON-NLS-1$
    interpreter.declareBean("dataFactoryContext", getDataFactoryContext(), ResourceBundleFactory.class); //$NON-NLS-1$
    if (script != null)
    {
      interpreter.exec(getLanguage(), "startup-script", 1, 1, getScript()); //$NON-NLS-1$
    }
  }

  /**
   * Queries a datasource. The string 'query' defines the name of the query. The Parameterset given here may contain
   * more data than actually needed for the query.
   * <p/>
   * The parameter-dataset may change between two calls, do not assume anything, and do not hold references to the
   * parameter-dataset or the position of the columns in the dataset.
   *
   * @param query      the query string
   * @param parameters the parameters for the query
   * @return the result of the query as table model.
   * @throws ReportDataFactoryException if an error occured while performing the query.
   */
  public TableModel queryData(final String query, final DataRow parameters) throws ReportDataFactoryException
  {
    final String queryScript = queries.get(query);
    if (queryScript == null)
    {
      throw new ReportDataFactoryException("No such query");
    }

    if (interpreter == null)
    {
      try
      {
        this.interpreter = createInterpreter();
      }
      catch (BSFException e)
      {
        throw new ReportDataFactoryException("Failed to initialize the BSF-Framework", e);
      }
    }

    try
    {
      dataRowWrapper.setParent(parameters);
      final Object o = interpreter.eval(getLanguage(), "expression", 1, 1, queryScript);
      if (o instanceof TableModel == false)
      {
        throw new ReportDataFactoryException("Resulting value is not a tablemodel");
      }
      return (TableModel) o; //$NON-NLS-1$
    }
    catch (ReportDataFactoryException rde)
    {
      throw rde;
    }
    catch (Exception e)
    {
      throw new ReportDataFactoryException("Evaluation error", e);
    }

  }

  public ScriptableDataFactory clone()
  {
    final ScriptableDataFactory dataFactory = (ScriptableDataFactory) super.clone();
    dataFactory.queries = (LinkedHashMap<String,String>) queries.clone();
    dataFactory.interpreter = null;
    dataFactory.dataRowWrapper = null;
    return dataFactory;
  }

  /**
   * Returns a copy of the data factory that is not affected by its anchestor and holds no connection to the anchestor
   * anymore. A data-factory will be derived at the beginning of the report processing.
   *
   * @return a copy of the data factory.
   */
  public DataFactory derive()
  {
    return clone();
  }

  /**
   * Closes the data factory and frees all resources held by this instance.
   */
  public void close()
  {
    if (this.interpreter != null && this.shutdownScript != null)
    {
      try
      {
        this.interpreter.eval(getLanguage(), "shutdown-script", 1, 1, getShutdownScript());
      }
      catch (BSFException e)
      {
        logger.warn("Failed to evaluate shutdown-script", e);
      }
    }
    this.dataRowWrapper = null;
    this.interpreter = null;
  }

  /**
   * Checks whether the query would be executable by this datafactory. This performs a rough check, not a full query.
   *
   * @param query
   * @param parameters
   * @return
   */
  public boolean isQueryExecutable(final String query, final DataRow parameters)
  {
    return queries.containsKey(query);
  }

  public void cancelRunningQuery()
  {
    // not all scripting engines actually support that.
    if (interpreter != null)
    {
      interpreter.terminate();
    }
  }
}
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