Calculating accuracy of a bayesian model

.gitignore

@@ -4,4 +4,5 @@
 *.jar
 *.war
 *.ear
-.DS_Store
+.DS_Store
+/target

src/main/java/com/nickferraro/bayesian/report/calc/IAccuracyCalculator.java

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+package com.nickferraro.bayesian.report.calc;
+
+import java.util.List;
+
+import com.nickferraro.bayesian.IDataRow;
+
+/**
+ * The IAccuracyCalculator interface is a simple contract for calculating the accuracy of
+ * a bayesian system in classifying a list of data rows.
+ * @author Nick Ferraro
+ *
+ * @param <T> The category data type the bayesian system will be using
+ */
+public interface IAccuracyCalculator<T> {
+	/**
+	 * Classify the list of data rows and calculate the accuracy of classifying the row category.
+	 * @param dataRows A list of data rows to classify and use in a clean set of calculations.
+	 * @return The accuracy of classifying this data set
+	 */
+	public double calculateAccuracy(List<IDataRow<T>> dataRows);
+
+	/**
+	 * Classify the list of data rows and calculate the accuracy of classifying the row category.
+	 * @param dataRows A list of data rows to classify and use in a clean or aggregated set of calculations.
+	 * @param cleanSlate Whether or not to aggregate previous calculations with this new data set or start from a clean slate. Defaults to TRUE.
+	 * @return The accuracy of classifying this data set
+	 */
+	public double calculateAccuracy(List<IDataRow<T>> dataRows, boolean cleanSlate);
+
+	/**
+	 * Get the last accuracy calculated.
+	 * @return The last accuracy calculated.
+	 */
+	public double getAccuracy();
+
+	/**
+	 * Get the number of correct classifications from the last calculation.
+	 * @return The number of correct classifications
+	 */
+	public int getCorrectCount();
+
+	/**
+	 * Get the number of incorrect classifications from the last calculation.
+	 * @return The number of incorrect classifications
+	 */
+	public int getIncorrectCount();
+
+	/**
+	 * Get the number of total classifications calculated
+	 * @return The number of total classifications
+	 */
+	public int getTotalCount();
+}

src/main/java/com/nickferraro/bayesian/report/calc/core/AccuracyCalculator.java

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+package com.nickferraro.bayesian.report.calc.core;
+
+import java.security.InvalidParameterException;
+import java.util.List;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import com.nickferraro.bayesian.IBayesianSystem;
+import com.nickferraro.bayesian.IClassification;
+import com.nickferraro.bayesian.IDataRow;
+import com.nickferraro.bayesian.report.calc.IAccuracyCalculator;
+
+/**
+ * A thread-safe implementation of IAccuracyCalculator. This class will classify data rows
+ * and return the accuracy rate calculated. Multiple sets of data rows can be classified and aggregated
+ * into a single accuracy calculation. This implementation does not use the IDataRow id, nor does
+ * it verify that duplicate ids are only counted once.
+ * @author Nick Ferraro
+ * 
+ * @param <T> The category data type the bayesian system will be using
+ */
+public class AccuracyCalculator<T> implements IAccuracyCalculator<T> {
+	protected final ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
+	protected final Lock readLock = readWriteLock.readLock();
+	protected final Lock writeLock = readWriteLock.writeLock();
+	protected IBayesianSystem<T> bayesianSystem;
+	protected int total = 0;
+	protected int correct = 0;
+
+	/**
+	 * Constructor for AccuracyCalculator. Requires a non-null IBayesianSystem parameter.
+	 * @param bayesianSystem The IBayesianSystem to use for classification. Must not be NULL.
+	 * @throws InvalidParameterException Thrown when IBayesianSystem is NULL.
+	 */
+	public AccuracyCalculator(IBayesianSystem<T> bayesianSystem) throws InvalidParameterException {
+		// DRY: Set the bayesian system and reset counts
+		setBayesianSystem(bayesianSystem);
+		resetCounts();
+	}
+
+	/**
+	 * Set the IBayesianSystem used for classification.
+	 * @param bayesianSystem The IBayesianSystem to use for classification. Must not be NULL.
+	 * @throws InvalidParameterException Thrown when IBayesianSystem is NULL.
+	 */
+	public void setBayesianSystem(IBayesianSystem<T> bayesianSystem) throws InvalidParameterException {
+		// Validate the bayesianSystem parameter
+		if( bayesianSystem == null ) {
+			throw new InvalidParameterException("AccuracyCalculator cannot set a NULL IBayesianSystem");
+		}
+
+		// Lock
+		writeLock.lock();
+
+		try {
+			this.bayesianSystem = bayesianSystem;
+		} finally {
+			// Unlock
+			writeLock.unlock();
+		}
+	}
+
+	@Override
+	public double calculateAccuracy(List<IDataRow<T>> dataRows) {
+		// DRY: Call calculateAccuracy with cleanSlate = TRUE
+		return calculateAccuracy(dataRows, true);
+	}
+
+	@Override
+	public double calculateAccuracy(List<IDataRow<T>> dataRows, boolean cleanSlate) {
+		// Lock
+		writeLock.lock();
+
+		try {
+			// Call thread-unsafe private method
+			return _calculateAccuracy(dataRows, cleanSlate);
+		} finally {
+			// Unlock
+			writeLock.unlock();
+		}
+	}
+
+	@Override
+	public double getAccuracy() {
+		// Lock
+		readLock.lock();
+
+		try {
+			// Call thead-unsafe private method
+			return _getAccuracy();
+		} finally {
+			// Unlock
+			readLock.unlock();
+		}
+	}
+
+	@Override
+	public int getCorrectCount() {
+		// Lock
+		readLock.lock();
+
+		try {
+			return correct;
+		} finally {
+			// Unlock
+			readLock.unlock();
+		}
+	}
+
+	@Override
+	public int getIncorrectCount() {
+		// Lock
+		readLock.lock();
+
+		try {
+			// Calculate and return incorrect
+			return total - correct;
+		} finally {
+			// Unlock
+			readLock.unlock();
+		}
+	}
+
+	@Override
+	public int getTotalCount() {
+		// Lock
+		readLock.lock();
+
+		try {
+			return total;
+		} finally {
+			// Unlock
+			readLock.unlock();
+		}
+	}
+
+	/**
+	 * Reset the current calculations and counts
+	 */
+	public void resetCounts() {
+		// Lock
+		writeLock.lock();
+
+		try {
+			// Call thread-unsafe private method
+			_resetCounts();
+		} finally {
+			writeLock.unlock();
+		}
+	}
+
+	/**
+	 * Private thread-unsafe method for calculating the accuracy of a bayesian system.
+	 * @param dataRows The data rows to classify and use in accuracy calculations
+	 * @param cleanSlate Whether or not to aggregate calculations or start from a clean slate
+	 * @return The current accuracy of the bayesian system
+	 */
+	protected double _calculateAccuracy(List<IDataRow<T>> dataRows, boolean cleanSlate) {
+		// Reset our counts if cleanSlate is TRUE
+		if( cleanSlate ) {
+			_resetCounts();
+		}
+
+		// Return 0% accuracy for null dataRows
+		if( dataRows == null ) {
+			return _getAccuracy();
+		}
+
+		// Iterate over data rows
+		for(IDataRow<T> dataRow : dataRows) {
+			// If a row is null, skip it
+			if( dataRow == null ) {
+				continue;
+			}
+
+			// Get the first classification and check if it is correct. NULL classifications are ignored.
+			List<IClassification<T>> classifications = bayesianSystem.classifyRow(dataRow);
+			if( classifications != null && classifications.size() > 0 ) {
+				IClassification<T> classification = classifications.get(0);
+				// Increase the total rows calculated
+				++total;
+
+				// If the classification category matches the data row category, increase the correct count
+				if( classification != null && classification.getCategory().equals(dataRow.getCategory()) ) {
+					++correct;
+				}
+			}
+		}
+
+		// Return the current accuracy using the thread-unsafe private method
+		return _getAccuracy();
+	}
+
+	/**
+	 * Private thread-unsafe method for calculating the accuracy
+	 * @return The last calculated accuracy
+	 */
+	protected double _getAccuracy() {
+		return total == 0 ? 0.0 : ((double)correct / (double)total);
+	}
+
+	/**
+	 * Private thread-unsafe method for reseting the calculations and counts
+	 */
+	protected void _resetCounts() {
+		total = 0;
+		correct = 0;
+	}
+}