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The Waikato Environment for Knowledge Analysis (WEKA), a machine
learning workbench. This version represents the developer version, the
"bleeding edge" of development, you could say. New functionality gets added
to this version.
/*
* 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 3 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, see m_Cache = new ArrayList();
/**
* 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 sends them to a "
+ "database.";
}
/**
* Sets up the database drivers
*
* @throws Exception if an error occurs
*/
public DatabaseResultListener() throws Exception {
super();
}
/**
* Prepare for the results to be received.
*
* @param rp the ResultProducer that will generate the results
* @throws Exception if an error occurs during preprocessing.
*/
@Override
public void preProcess(ResultProducer rp) throws Exception {
m_ResultProducer = rp;
// Connect to the database and find out what table corresponds to this
// ResultProducer
updateResultsTableName(m_ResultProducer);
}
/**
* 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
* @throws Exception if an error occurs
*/
@Override
public void postProcess(ResultProducer rp) throws Exception {
if (m_ResultProducer != rp) {
throw new Error("Unrecognized ResultProducer calling postProcess!!");
}
disconnectFromDatabase();
}
/**
* Determines if there are any constraints (imposed by the destination) on any
* additional measures produced by resultProducers. Null should be returned if
* there are NO constraints, otherwise a list of column names should be
* returned as an array of Strings. In the case of DatabaseResultListener, the
* structure of an existing database will impose constraints.
*
* @param rp the ResultProducer to which the constraints will apply
* @return an array of column names to which resutltProducer's results will be
* restricted.
* @throws Exception if an error occurs.
*/
@Override
public String[] determineColumnConstraints(ResultProducer rp)
throws Exception {
ArrayList cNames = new ArrayList();
updateResultsTableName(rp);
DatabaseMetaData dbmd = m_Connection.getMetaData();
ResultSet rs;
// gets a result set where each row is info on a column
if (m_checkForUpperCaseNames) {
rs = dbmd.getColumns(null, null, m_ResultsTableName.toUpperCase(), null);
} else {
rs = dbmd.getColumns(null, null, m_ResultsTableName, null);
}
boolean tableExists = false;
int numColumns = 0;
while (rs.next()) {
tableExists = true;
// column four contains the column name
String name = rs.getString(4);
if (name.toLowerCase().startsWith("measure")) {
numColumns++;
cNames.add(name);
}
}
// no constraints on any additional measures if the table does not exist
if (!tableExists) {
return null;
}
// a zero element array indicates maximum constraint
String[] columnNames = new String[numColumns];
for (int i = 0; i < numColumns; i++) {
columnNames[i] = (cNames.get(i));
}
return columnNames;
}
/**
* Submit the result to the appropriate table of the database
*
* @param rp the ResultProducer that generated the result
* @param key The key for the results.
* @param result The actual results.
* @throws Exception if the result couldn't be sent to the database
*/
@Override
public void acceptResult(ResultProducer rp, Object[] key, Object[] result)
throws Exception {
if (m_ResultProducer != rp) {
throw new Error("Unrecognized ResultProducer calling acceptResult!!");
}
// null result could occur from a chain of doRunKeys calls
if (result != null) {
putResultInTable(m_ResultsTableName, rp, key, result);
}
}
/**
* Always says a result is required. If this is the first call, prints out the
* header for the Database output.
*
* @param rp the ResultProducer wanting to generate the result
* @param key The key for which a result may be needed.
* @return true if the result should be calculated.
* @throws Exception if the database couldn't be queried
*/
@Override
public boolean isResultRequired(ResultProducer rp, Object[] key)
throws Exception {
if (m_ResultProducer != rp) {
throw new Error("Unrecognized ResultProducer calling isResultRequired!");
}
if (m_Debug) {
System.err.print("Is result required...");
for (Object element : key) {
System.err.print(" " + element);
}
System.err.flush();
}
boolean retval = false;
// Check the key cache first
if (!m_CacheKeyName.equals("")) {
if (!isCacheValid(key)) {
loadCache(rp, key);
}
retval = !isKeyInCache(rp, key);
} else {
// Ask whether the results are needed
retval = !isKeyInTable(m_ResultsTableName, rp, key);
}
if (m_Debug) {
System.err.println(" ..." + (retval ? "required" : "not required")
+ (m_CacheKeyName.equals("") ? "" : " (cache)"));
System.err.flush();
}
return retval;
}
/**
* Determines the table name that results will be inserted into. If required:
* a connection will be opened, an experiment index table created, and the
* results table created.
*
* @param rp the ResultProducer
* @throws Exception if an error occurs
*/
protected void updateResultsTableName(ResultProducer rp) throws Exception {
if (!isConnected()) {
connectToDatabase();
}
if (!experimentIndexExists()) {
createExperimentIndex();
}
String tableName = getResultsTableName(rp);
if (tableName == null) {
tableName = createExperimentIndexEntry(rp);
}
if (!tableExists(tableName)) {
createResultsTable(rp, tableName);
}
m_ResultsTableName = tableName;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for displaying in the
* explorer/experimenter gui
*/
public String cacheKeyNameTipText() {
return "Set the name of the key field by which to cache.";
}
/**
* Get the value of CacheKeyName.
*
* @return Value of CacheKeyName.
*/
public String getCacheKeyName() {
return m_CacheKeyName;
}
/**
* Set the value of CacheKeyName.
*
* @param newCacheKeyName Value to assign to CacheKeyName.
*/
public void setCacheKeyName(String newCacheKeyName) {
m_CacheKeyName = newCacheKeyName;
}
/**
* Checks whether the current cache contents are valid for the supplied key.
*
* @param key the results key
* @return true if the cache contents are valid for the key given
*/
protected boolean isCacheValid(Object[] key) {
if (m_CacheKey == null) {
return false;
}
if (m_CacheKey.length != key.length) {
return false;
}
for (int i = 0; i < key.length; i++) {
if ((i != m_CacheKeyIndex) && (!m_CacheKey[i].equals(key[i]))) {
return false;
}
}
return true;
}
/**
* Returns true if the supplied key is in the key cache (and thus we do not
* need to execute a database query).
*
* @param rp the ResultProducer the key belongs to.
* @param key the result key
* @return true if the key is in the key cache
* @throws Exception if an error occurs
*/
protected boolean isKeyInCache(ResultProducer rp, Object[] key)
throws Exception {
for (int i = 0; i < m_Cache.size(); i++) {
if (m_Cache.get(i).equals(key[m_CacheKeyIndex])) {
return true;
}
}
return false;
}
/**
* Executes a database query to fill the key cache
*
* @param rp the ResultProducer the key belongs to
* @param key the key
* @throws Exception if an error occurs
*/
protected void loadCache(ResultProducer rp, Object[] key) throws Exception {
System.err.print(" (updating cache)");
System.err.flush();
m_Cache.clear();
m_CacheKey = null;
String query = "SELECT Key_" + m_CacheKeyName + " FROM "
+ m_ResultsTableName;
String[] keyNames = rp.getKeyNames();
if (keyNames.length != key.length) {
throw new Exception("Key names and key values of different lengths");
}
m_CacheKeyIndex = -1;
for (int i = 0; i < keyNames.length; i++) {
if (keyNames[i].equalsIgnoreCase(m_CacheKeyName)) {
m_CacheKeyIndex = i;
break;
}
}
if (m_CacheKeyIndex == -1) {
throw new Exception("No key field named " + m_CacheKeyName
+ " (as specified for caching)");
}
boolean first = true;
for (int i = 0; i < key.length; i++) {
if ((key[i] != null) && (i != m_CacheKeyIndex)) {
if (first) {
query += " WHERE ";
first = false;
} else {
query += " AND ";
}
query += "Key_" + keyNames[i] + '=';
if (key[i] instanceof String) {
query += "'" + DatabaseUtils.processKeyString(key[i].toString())
+ "'";
} else {
query += key[i].toString();
}
}
}
ResultSet rs = select(query);
while (rs.next()) {
String keyVal = rs.getString(1);
if (!rs.wasNull()) {
m_Cache.add(keyVal);
}
}
close(rs);
m_CacheKey = key.clone();
}
/**
* Returns the revision string.
*
* @return the revision
*/
@Override
public String getRevision() {
return RevisionUtils.extract("$Revision: 11247 $");
}
}
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