content: /*
   *    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.
   */
  
  /*
   * MultiFilter.java
   * Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
   *
   */
  
  
  package weka.filters;
  
  import weka.core.Capabilities;
  import weka.core.Instance;
  import weka.core.Instances;
  import weka.core.Option;
  import weka.core.OptionHandler;
  import weka.core.RevisionUtils;
  import weka.core.Utils;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  /** 
   <!-- globalinfo-start -->
   * Applies several filters successively. In case all supplied filters are StreamableFilters, it will act as a streamable one, too.
   * <p/>
   <!-- globalinfo-end -->
   *
   <!-- options-start -->
   * Valid options are: <p/>
   * 
   * <pre> -D
   *  Turns on output of debugging information.</pre>
   * 
   * <pre> -F &lt;classname [options]&gt;
   *  A filter to apply (can be specified multiple times).</pre>
   * 
   <!-- options-end -->
   *
   * @author  FracPete (fracpete at waikato dot ac dot nz)
   * @version $Revision: 6945 $
   * @see     weka.filters.StreamableFilter
   */
  public class MultiFilter
    extends SimpleStreamFilter {
  
    /** for serialization */
    private static final long serialVersionUID = -6293720886005713120L;
  
    /** The filters */
    protected Filter m_Filters[] = {new AllFilter()};
  
    /** caches the streamable state */
    protected boolean m_Streamable = false;
  
    /** whether we already checked the streamable state */
    protected boolean m_StreamableChecked = false;
    
    /**
     * Returns a string describing this filter
     * @return 		a description of the filter suitable for
     * 			displaying in the explorer/experimenter gui
     */
    public String globalInfo() {
      return 
          "Applies several filters successively. In case all supplied filters " 
        + "are StreamableFilters, it will act as a streamable one, too.";
    }
  
    /**
     * Returns an enumeration describing the available options.
     *
     * @return 		an enumeration of all the available options.
     */
    public Enumeration listOptions() {
      Vector result = new Vector();
      Enumeration enm = super.listOptions();
      while (enm.hasMoreElements())
        result.add(enm.nextElement());
        
      result.addElement(new Option(
                "\tA filter to apply (can be specified multiple times).",
                "F", 1, "-F <classname [options]>"));
  
      return result.elements();
    }
  
    /**
     * Parses a list of options for this object. <p/>
     *
     <!-- options-start -->
     * Valid options are: <p/>
     * 
     * <pre> -D
     *  Turns on output of debugging information.</pre>
     * 
     * <pre> -F &lt;classname [options]&gt;
     *  A filter to apply (can be specified multiple times).</pre>
     * 
     <!-- options-end -->
     *
     * @param options 	the list of options as an array of strings
     * @throws Exception 	if an option is not supported
     */
    public void setOptions(String[] options) throws Exception {
      String        tmpStr;
      String        filter;
      String[]      options2;
      Vector        filters;
  
      super.setOptions(options);
      
      filters = new Vector();
      while ((tmpStr = Utils.getOption("F", options)).length() != 0) {
        options2    = Utils.splitOptions(tmpStr);
        filter      = options2[0];
        options2[0] = "";
        filters.add(Utils.forName(Filter.class, filter, options2));
      }
  
      // at least one filter
      if (filters.size() == 0)
        filters.add(new AllFilter());
  
      setFilters((Filter[]) filters.toArray(new Filter[filters.size()]));
    }
  
    /**
     * Gets the current settings of the filter.
     *
     * @return 		an array of strings suitable for passing to setOptions
     */
    public String[] getOptions() {
      Vector        result;
      String[]      options;
      int           i;
  
      result = new Vector();
  
      options = super.getOptions();
      for (i = 0; i < options.length; i++)
        result.add(options[i]);
      
      for (i = 0; i < getFilters().length; i++) {
        result.add("-F");
        result.add(getFilterSpec(getFilter(i)));
      }
  
      return (String[]) result.toArray(new String[result.size()]);
    }
  
    /** 
     * Returns the Capabilities of this filter.
     *
     * @return            the capabilities of this object
     * @see               Capabilities
     */
    public Capabilities getCapabilities() {
      if (getFilters().length == 0) {
        Capabilities result = super.getCapabilities();
        result.disableAll();
        
        return result;
      } else {
        return getFilters()[0].getCapabilities();
      }
    }
  
    /**
     * resets the filter, i.e., m_NewBatch to true and m_FirstBatchDone to
     * false.
     *
     * @see #m_NewBatch
     * @see #m_FirstBatchDone
     */
    protected void reset() {
      super.reset();
      m_StreamableChecked = false;
    }
  
    /**
     * Sets the list of possible filters to choose from.
     * Also resets the state of the filter (this reset doesn't affect the 
     * options).
     *
     * @param filters	an array of filters with all options set.
     * @see #reset()
     */
    public void setFilters(Filter[] filters) {
      m_Filters           = filters;
      reset();
    }
  
    /**
     * Gets the list of possible filters to choose from.
     *
     * @return 	the array of Filters
     */
    public Filter[] getFilters() {
      return m_Filters;
    }
    
    /**
     * Returns the tip text for this property
     * @return    tip text for this property suitable for
     *            displaying in the explorer/experimenter gui
     */
    public String filtersTipText() {
      return "The base filters to be used.";
    }
    
    /**
     * Gets a single filter from the set of available filters.
     *
     * @param 	index the index of the filter wanted
     * @return 	the Filter
     */
    public Filter getFilter(int index) {
      return m_Filters[index];
    }
  
    /**
     * returns the filter classname and the options as one string
     * 
     * @param filter	the filter to get the specs for
     * @return		the classname plus options
     */
    protected String getFilterSpec(Filter filter) {
      String        result;
  
      if (filter == null) {
        result = "";
      }
      else {
        result  = filter.getClass().getName();
        if (filter instanceof OptionHandler)
          result += " " 
            + Utils.joinOptions(((OptionHandler) filter).getOptions());
      }
  
      return result;
    }
  
    /**
     * tests whether all the enclosed filters are streamable
     *
     * @return	true if all the enclosed filters are streamable
     */
    public boolean isStreamableFilter() {
      int           i;
  
      if (!m_StreamableChecked) {
        m_Streamable        = true;
        m_StreamableChecked = true;
  
        for (i = 0; i < getFilters().length; i++) {
          if (getFilter(i) instanceof MultiFilter)
            m_Streamable = ((MultiFilter) getFilter(i)).isStreamableFilter();
          else if (getFilter(i) instanceof StreamableFilter)
            m_Streamable = true;
          else
            m_Streamable = false;
  
          if (!m_Streamable)
            break;
        }
  
        if (getDebug())
          System.out.println("Streamable: " + m_Streamable);
      }
  
      return m_Streamable;
    }
  
    /**
     * Returns true if the output format is immediately available after the
     * input format has been set and not only after all the data has been
     * seen (see batchFinished()). This method should normally return true
     * for a stream filter, since the data will be processed in a batch
     * manner instead (or at least for the second batch of files, see
     * m_FirstBatchDone).
     *
     * @return      true if the output format is immediately available
     * @see         #batchFinished()
     * @see         #setInputFormat(Instances)
     * @see         #m_FirstBatchDone
     */
    protected boolean hasImmediateOutputFormat() {
      return isStreamableFilter();
    }
    
    /**
     * Determines the output format based on the input format and returns 
     * this. In case the output format cannot be returned immediately, i.e.,
     * hasImmediateOutputFormat() returns false, then this method will called
     * from batchFinished() after the call of preprocess(Instances), in which,
     * e.g., statistics for the actual processing step can be gathered.
     *
     * @param inputFormat     the input format to base the output format on
     * @return                the output format
     * @throws Exception      in case the determination goes wrong
     * @see                   #hasImmediateOutputFormat()
     * @see                   #batchFinished()
     * @see                   #preprocess(Instances)
     */
    protected Instances determineOutputFormat(Instances inputFormat) throws Exception {
      Instances   result;
      int         i;
      
      result = getInputFormat();
      
      for (i = 0; i < getFilters().length; i++) {
        if (!isFirstBatchDone())
  	getFilter(i).setInputFormat(result);
        result = getFilter(i).getOutputFormat();
      }
  
      return result;
    }
  
    /**
     * processes the given instance (may change the provided instance) and
     * returns the modified version.
     *
     * @param instance    the instance to process
     * @return            the modified data
     * @throws Exception  in case the processing goes wrong
     */
    protected Instance process(Instance instance) throws Exception {
      Instance    result;
      int         i;
      
      result = (Instance) instance.copy();
  
      for (i = 0; i < getFilters().length; i++) {
        getFilter(i).input(result);
        result = getFilter(i).output();
      }
  
      return result;
    }
  
    /**
     * Processes the given data (may change the provided dataset) and returns
     * the modified version. This method is called in batchFinished().
     * This implementation only calls process(Instance) for each instance
     * in the given dataset.
     *
     * @param instances   the data to process
     * @return            the modified data
     * @throws Exception  in case the processing goes wrong
     * @see               #batchFinished()
     * @see               #process(Instance)
     */
    protected Instances process(Instances instances) throws Exception {
      Instances     result;
      int           i;
  
      result = instances;
      
      for (i = 0; i < getFilters().length; i++) {
        if (!isFirstBatchDone())
  	getFilter(i).setInputFormat(result);
        result = Filter.useFilter(result, getFilter(i));
      }
      
      return result;
    }
    
    /**
     * Signify that this batch of input to the filter is finished. If
     * the filter requires all instances prior to filtering, output()
     * may now be called to retrieve the filtered instances. Any
     * subsequent instances filtered should be filtered based on setting
     * obtained from the first batch (unless the setInputFormat has been
     * re-assigned or new options have been set).
     *
     * @return            true if there are instances pending output
     * @throws IllegalStateException      if no input format has been set. 
     */
    public boolean batchFinished() throws Exception {
      super.batchFinished();
      
      for (int i = 0; i > getFilters().length; i++) {
        getFilter(i).batchFinished();
      }
      
      return (numPendingOutput() != 0);
    }
    
    /**
     * RemoveWithValues may return false from input() (thus not
     * making an instance available immediately) even after
     * the first batch has been completed due to matching a value
     * that the user wants to remove. Therefore this method returns
     * true.
     * 
     * @return true if one of the base filters returns true for
     * this method.
     */
    public boolean mayRemoveInstanceAfterFirstBatchDone() {
      boolean result = false;
      
      for (Filter f : m_Filters) {
        result = (result || f.mayRemoveInstanceAfterFirstBatchDone());
      }
      
      return result;
    }
    
    /**
     * Returns the revision string.
     * 
     * @return		the revision
     */
    public String getRevision() {
      return RevisionUtils.extract("$Revision: 6945 $");
    }
  
    /**
     * Main method for executing this class.
     *
     * @param args should contain arguments for the filter: use -h for help
     */
    public static void main(String[] args) {
      runFilter(new MultiFilter(), args);
    }
  }
  