Java tutorial
/* * 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. */ /* * InstancesResultListener.java * Copyright (C) 1999 University of Waikato * */ package milk.experiment; import weka.core.Utils; import java.io.PrintWriter; import java.io.IOException; import java.io.File; import java.io.BufferedOutputStream; import java.io.FileOutputStream; import weka.core.OptionHandler; import java.util.Enumeration; import java.util.Vector; import weka.core.Option; import weka.core.Instances; import java.util.Hashtable; import weka.core.FastVector; import weka.core.Attribute; import weka.core.Instance; /** * InstancesResultListener outputs the received results in arff format to * a Writer. All results must be received before the instances can be * written out. * * @author Len Trigg (trigg@cs.waikato.ac.nz) * @version $Revision: 1.6 $ */ public class MIInstancesResultListener extends MICSVResultListener { /** Stores the instances created so far, before assigning to a header */ protected transient FastVector m_Instances; /** Stores the attribute types for each column */ protected transient int[] m_AttributeTypes; /** For lookup of indices given a string value for each nominal attribute */ protected transient Hashtable[] m_NominalIndexes; /** Contains strings seen so far for each nominal attribute */ protected transient FastVector[] m_NominalStrings; /** * Returns a string describing this result listener * @return a description of the result listener suitable for * displaying in the explorer/experimenter gui */ public String globalInfo() { return "Takes results from a result producer and assembles them into " + "a set of instances."; } /** * Prepare for the results to be received. * * @param rp the ResultProducer that will generate the results * @exception Exception if an error occurs during preprocessing. */ public void preProcess(MIResultProducer rp) throws Exception { m_RP = rp; if ((m_OutputFile == null) || (m_OutputFile.getName().equals("-"))) { m_Out = new PrintWriter(System.out, true); } else { m_Out = new PrintWriter(new BufferedOutputStream(new FileOutputStream(m_OutputFile)), true); } Object[] keyTypes = m_RP.getKeyTypes(); Object[] resultTypes = m_RP.getResultTypes(); m_AttributeTypes = new int[keyTypes.length + resultTypes.length]; m_NominalIndexes = new Hashtable[m_AttributeTypes.length]; m_NominalStrings = new FastVector[m_AttributeTypes.length]; m_Instances = new FastVector(); for (int i = 0; i < m_AttributeTypes.length; i++) { Object attribute = null; if (i < keyTypes.length) { attribute = keyTypes[i]; } else { attribute = resultTypes[i - keyTypes.length]; } if (attribute instanceof String) { m_AttributeTypes[i] = Attribute.NOMINAL; m_NominalIndexes[i] = new Hashtable(); m_NominalStrings[i] = new FastVector(); } else if (attribute instanceof Double) { m_AttributeTypes[i] = Attribute.NUMERIC; } else { throw new Exception("Unknown attribute type in column " + (i + 1)); } } } /** * Perform any postprocessing. When this method is called, it indicates * that no more results will be sent that need to be grouped together * in any way. * * @param rp the ResultProducer that generated the results * @exception Exception if an error occurs */ public void postProcess(MIResultProducer rp) throws Exception { if (m_RP != rp) { throw new Error("Unrecognized ResultProducer sending results!!"); } String[] keyNames = m_RP.getKeyNames(); String[] resultNames = m_RP.getResultNames(); FastVector attribInfo = new FastVector(); for (int i = 0; i < m_AttributeTypes.length; i++) { String attribName = "Unknown"; if (i < keyNames.length) { attribName = "Key_" + keyNames[i]; } else { attribName = resultNames[i - keyNames.length]; } switch (m_AttributeTypes[i]) { case Attribute.NOMINAL: if (m_NominalStrings[i].size() > 0) { attribInfo.addElement(new Attribute(attribName, m_NominalStrings[i])); } else { attribInfo.addElement(new Attribute(attribName, (FastVector) null)); } break; case Attribute.NUMERIC: attribInfo.addElement(new Attribute(attribName)); break; case Attribute.STRING: attribInfo.addElement(new Attribute(attribName, (FastVector) null)); break; default: throw new Exception("Unknown attribute type"); } } Instances result = new Instances("InstanceResultListener", attribInfo, m_Instances.size()); for (int i = 0; i < m_Instances.size(); i++) { result.add((Instance) m_Instances.elementAt(i)); } m_Out.println(new Instances(result, 0)); for (int i = 0; i < result.numInstances(); i++) { m_Out.println(result.instance(i)); } if (!(m_OutputFile == null) && !(m_OutputFile.getName().equals("-"))) { m_Out.close(); } } /** * Collects each instance and adjusts the header information. * * @param rp the ResultProducer that generated the result * @param key The key for the results. * @param result The actual results. * @exception Exception if the result could not be accepted. */ public void acceptResult(MIResultProducer rp, Object[] key, Object[] result) throws Exception { if (m_RP != rp) { throw new Error("Unrecognized ResultProducer sending results!!"); } Instance newInst = new Instance(m_AttributeTypes.length); for (int i = 0; i < m_AttributeTypes.length; i++) { Object val = null; if (i < key.length) { val = key[i]; } else { val = result[i - key.length]; } if (val == null) { newInst.setValue(i, Instance.missingValue()); } else { switch (m_AttributeTypes[i]) { case Attribute.NOMINAL: String str = (String) val; Double index = (Double) m_NominalIndexes[i].get(str); if (index == null) { index = new Double(m_NominalStrings[i].size()); m_NominalIndexes[i].put(str, index); m_NominalStrings[i].addElement(str); } newInst.setValue(i, index.doubleValue()); break; case Attribute.NUMERIC: double dou = ((Double) val).doubleValue(); newInst.setValue(i, (double) dou); break; default: newInst.setValue(i, Instance.missingValue()); } } } m_Instances.addElement(newInst); } } // InstancesResultListener