#75 Added transaction logic

src/main/java/de/rwu/easydrop/core/Core.java

@@ -9,13 +9,17 @@ import org.slf4j.LoggerFactory;
 import org.sqlite.SQLiteDataSource;
 
 import de.rwu.easydrop.api.client.DataSourceFactory;
+import de.rwu.easydrop.api.dto.OfferDTO;
 import de.rwu.easydrop.data.connector.OfferPersistenceInterface;
 import de.rwu.easydrop.data.connector.ProductPersistenceInterface;
 import de.rwu.easydrop.data.connector.SQLiteConnector;
+import de.rwu.easydrop.data.connector.TransactionPersistenceInterface;
 import de.rwu.easydrop.model.Offer;
 import de.rwu.easydrop.model.ProductCatalogue;
+import de.rwu.easydrop.service.mapping.OfferMapper;
 import de.rwu.easydrop.service.processing.OfferIdentifier;
 import de.rwu.easydrop.service.processing.OfferProvisioner;
+import de.rwu.easydrop.service.processing.TransactionHandler;
 import de.rwu.easydrop.service.retriever.CatalogueRetriever;
 import de.rwu.easydrop.service.retriever.ProductRetriever;
 import de.rwu.easydrop.service.writer.CatalogueWriter;
@@ -57,6 +61,7 @@ public final class Core {
         ProductRetriever retriever = new ProductRetriever(dataSourceFactory, pdb);
         CatalogueRetriever catRetriever = new CatalogueRetriever(pConfig, retriever);
         CatalogueWriter catWriter = new CatalogueWriter(pdb);
+        TransactionPersistenceInterface tpi = new SQLiteConnector(new SQLiteDataSource());
 
         LOGGER.info("Loading catalogues");
         catRetriever.loadCatalogues();
@@ -70,8 +75,12 @@ public final class Core {
         provis.runProvisioner(identifiedOffers);
 
         LOGGER.info("Creating transactions");
-        // Transaction logic!
+        TransactionHandler txHandler = new TransactionHandler(tpi);
+        for (OfferDTO o : odb.getOffers()) {
+            txHandler.turnOfferToTransaction(OfferMapper.mapOfferFromDTO(o));
+        }
 
-        LOGGER.info("Done!");
+        tpi.outputTransactionsToLog();
+        tpi.outputSummaryToLog();
     }
 }

src/main/java/de/rwu/easydrop/data/connector/OfferPersistenceInterface.java

@@ -1,7 +1,14 @@
 package de.rwu.easydrop.data.connector;
 
+import java.util.List;
+
 import de.rwu.easydrop.api.dto.OfferDTO;
 
+/**
+ * Interface to offer persistence.
+ *
+ * @since 0.3.0
+ */
 public interface OfferPersistenceInterface {
     /**
      * Writes a ProductDTO to persistence.
@@ -19,7 +26,21 @@ public interface OfferPersistenceInterface {
     OfferDTO getOfferDTOById(String offerId);
 
     /**
-     * Deletes all data from persistence.
+     * Gets all offerDTOs from persistence.
+     *
+     * @return offerDTOs
      */
-    void clearData();
+    List<OfferDTO> getOffers();
+
+    /**
+     * Deletes all offer data from persistence.
+     */
+    void clearOfferData();
+
+    /**
+     * Deletes an offer from persistence.
+     *
+     * @param offerId
+     */
+    void deleteOfferById(String offerId);
 }

src/main/java/de/rwu/easydrop/data/connector/ProductPersistenceInterface.java

@@ -24,7 +24,7 @@ public interface ProductPersistenceInterface {
     ProductDTO getProductDTOById(String productId);
 
     /**
-     * Deletes all data from persistence.
+     * Deletes all product data from persistence.
      */
-    void clearData();
+    void clearProductData();
 }

src/main/java/de/rwu/easydrop/data/connector/SQLiteConnector.java

@@ -5,13 +5,19 @@ import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.sqlite.SQLiteDataSource;
 
 import de.rwu.easydrop.api.dto.OfferDTO;
 import de.rwu.easydrop.api.dto.ProductDTO;
+import de.rwu.easydrop.api.dto.TransactionDTO;
 import de.rwu.easydrop.exception.PersistenceException;
 import de.rwu.easydrop.model.Webshop;
+import de.rwu.easydrop.util.FormattingUtil;
 
 /**
  * Allows connecting to a SQLite Database.
@@ -19,7 +25,18 @@ import de.rwu.easydrop.model.Webshop;
  * @since 0.2.0
  */
 public final class SQLiteConnector implements
-        ProductPersistenceInterface, OfferPersistenceInterface {
+        ProductPersistenceInterface, OfferPersistenceInterface,
+        TransactionPersistenceInterface {
+    /**
+     * Base for calculating percentages.
+     */
+    private static final int PERCENT = 100;
+
+    /**
+     * Logging instance.
+     */
+    private static final Logger LOGGER = LoggerFactory.getLogger(SQLiteConnector.class);
+
     /**
      * SQLite Database.
      */
@@ -41,6 +58,11 @@ public final class SQLiteConnector implements
      */
     private static final String LAST_UPDATE_COL_NAME = "lastUpdate";
 
+    /**
+     * Name of 'offerId' column.
+     */
+    private static final String OFFERID_COL_NAME = "offerId";
+
     /**
      * Creates instance.
      *
@@ -89,6 +111,16 @@ public final class SQLiteConnector implements
                             + ")");
             createOffers.close();
 
+            Statement createTransactions = connection.createStatement();
+            createTransactions.execute(
+                    "CREATE TABLE IF NOT EXISTS transactions ("
+                            + "offerId TEXT, "
+                            + "earnings REAL, "
+                            + "volume REAL, "
+                            + "transactionTime TEXT"
+                            + ")");
+            createTransactions.close();
+
             // Close the connection
             connection.close();
         } catch (SQLException e) {
@@ -105,7 +137,7 @@ public final class SQLiteConnector implements
         String query = "INSERT INTO products ("
                 + "dataOrigin, productId, currentPrice, merchant, "
                 + "deliveryPrice, available, lastUpdate"
-                + ") VALUES ("
+                + ") VALUES ( "
                 + "?, ?, ?, ?, ?, ?, ?"
                 + ")";
 
@@ -123,7 +155,8 @@ public final class SQLiteConnector implements
 
             statement.executeUpdate();
         } catch (SQLException e) {
-            throw new PersistenceException("Something went wrong while saving to SQLite", e);
+            throw new PersistenceException(
+                    "Something went wrong while saving product to SQLite", e);
         }
     }
 
@@ -156,7 +189,8 @@ public final class SQLiteConnector implements
                 }
             }
         } catch (SQLException e) {
-            throw new PersistenceException("Something went wrong while reading from SQLite");
+            throw new PersistenceException(
+                    "Something went wrong while reading product from SQLite");
         }
 
         return dto;
@@ -168,16 +202,9 @@ public final class SQLiteConnector implements
      * @throws SQLException
      */
     public void clearData() {
-        try (Connection connection = db.getConnection();
+        clearProductData();
-                Statement statement = connection.createStatement()) {
+        clearOfferData();
-
+        clearTXData();
-            String productsQuery = "DELETE FROM products;";
-            String offersQuery = "DELETE FROM offers;";
-            statement.executeUpdate(productsQuery);
-            statement.executeUpdate(offersQuery);
-        } catch (SQLException e) {
-            throw new PersistenceException("Something went wrong while clearing the database", e);
-        }
     }
 
     /**
@@ -202,17 +229,18 @@ public final class SQLiteConnector implements
             ProductDTO targetProduct = dto.getTargetProduct();
 
             statement.setString(++index, dto.getOfferId());
-            statement.setString(++index, sourceProduct.getProductId());
             statement.setString(++index, sourceProduct.getDataOrigin().toString());
+            statement.setString(++index, sourceProduct.getProductId());
             statement.setDouble(++index, sourceProduct.getCurrentPrice());
-            statement.setString(++index, targetProduct.getProductId());
             statement.setString(++index, targetProduct.getDataOrigin().toString());
+            statement.setString(++index, targetProduct.getProductId());
             statement.setDouble(++index, targetProduct.getCurrentPrice());
             statement.setString(++index, dto.getLastUpdate());
 
             statement.executeUpdate();
         } catch (SQLException e) {
-            throw new PersistenceException("Something went wrong while saving to SQLite", e);
+            throw new PersistenceException(
+                    "Something went wrong while saving offer to SQLite", e);
         }
     }
 
@@ -234,24 +262,186 @@ public final class SQLiteConnector implements
             try (ResultSet resultSet = statement.executeQuery()) {
                 if (resultSet.next()) {
                     dto = new OfferDTO();
-                    ProductDTO srcProduct = new ProductDTO(
+                    ProductDTO srcProduct = getProductDTOById(resultSet.getString("sourceId"));
-                            resultSet.getString("sourceId"),
+                    ProductDTO targetProduct = getProductDTOById(resultSet.getString("targetId"));
-                            Webshop.fromString(resultSet.getString("sourceWebshop")));
+                    dto.setOfferId(resultSet.getString(OFFERID_COL_NAME));
-                    srcProduct.setCurrentPrice(resultSet.getDouble("sourcePrice"));
-                    ProductDTO targetProduct = new ProductDTO(
-                            resultSet.getString("targetId"),
-                            Webshop.fromString(resultSet.getString("targetWebshop")));
-                    srcProduct.setCurrentPrice(resultSet.getDouble("targetPrice"));
-                    dto.setOfferId(resultSet.getString("offerId"));
                     dto.setSourceProduct(srcProduct);
                     dto.setTargetProduct(targetProduct);
                     dto.setLastUpdate(resultSet.getString(LAST_UPDATE_COL_NAME));
                 }
             }
         } catch (SQLException e) {
-            throw new PersistenceException("Something went wrong while reading from SQLite", e);
+            throw new PersistenceException(
+                    "Something went wrong while reading offer from SQLite", e);
         }
 
         return dto;
     }
+
+    @Override
+    public void writeTX(final TransactionDTO dto) {
+        String query = "INSERT INTO transactions ("
+                + "offerId, volume, earnings, transactionTime"
+                + ") VALUES ("
+                + "?, ?, ?, ?"
+                + ")";
+
+        try (Connection connection = db.getConnection();
+                PreparedStatement statement = connection.prepareStatement(query)) {
+            int index = 0;
+
+            statement.setString(++index, dto.getOfferId());
+            statement.setDouble(++index, dto.getVolume());
+            statement.setDouble(++index, dto.getEarnings());
+            statement.setString(++index, dto.getTransactionTime());
+
+            statement.executeUpdate();
+        } catch (SQLException e) {
+            throw new PersistenceException(
+                    "Something went wrong while saving transaction to SQLite", e);
+        }
+    }
+
+    @Override
+    public void outputTransactionsToLog() {
+        String query = "SELECT * FROM transactions t "
+                + "LEFT JOIN offers o ON t.offerId = o.offerId "
+                + "ORDER BY transactionTime ASC";
+        StringBuilder sb = new StringBuilder();
+        int index = 0;
+        sb.append("Transaction History:");
+
+        try (Connection connection = db.getConnection();
+                PreparedStatement statement = connection.prepareStatement(query)) {
+
+            try (ResultSet resultSet = statement.executeQuery()) {
+                while (resultSet.next()) {
+                    sb.append("\n");
+                    sb.append(String.format("%3d", ++index));
+                    sb.append(String.format(" - %s - ", resultSet.getString("transactionTime")));
+                    sb.append(String.format("+%s (%s) - %s",
+                            FormattingUtil.formatEuro(resultSet.getDouble("earnings")),
+                            FormattingUtil.formatEuro(resultSet.getDouble("volume")),
+                            resultSet.getString(OFFERID_COL_NAME)));
+                }
+            }
+        } catch (SQLException e) {
+            throw new PersistenceException(
+                    "Something went wrong while reading transaction from SQLite", e);
+        }
+
+        String logString = sb.toString();
+        LOGGER.info(logString);
+    }
+
+    @Override
+    public void outputSummaryToLog() {
+        String query = "SELECT SUM(earnings) AS earnings, SUM(volume) AS volume FROM transactions;";
+        StringBuilder sb = new StringBuilder();
+        sb.append("Summary:\n");
+
+        try (Connection connection = db.getConnection();
+                PreparedStatement statement = connection.prepareStatement(query)) {
+
+            try (ResultSet resultSet = statement.executeQuery()) {
+                if (resultSet.next()) {
+                    double earnings = resultSet.getDouble("earnings");
+                    double volume = resultSet.getDouble("volume");
+                    String avgMargin = String.valueOf(
+                            Math.round(earnings / volume * PERCENT)) + "%";
+
+                    String earningsFormatted = FormattingUtil.formatEuro(earnings);
+                    String volumeFormatted = FormattingUtil.formatEuro(volume);
+
+                    sb.append(String.format("Total earnings: %s, ", earningsFormatted));
+                    sb.append(String.format("total volume: %s ", volumeFormatted));
+                    sb.append(String.format("(average margin %s)", avgMargin));
+                }
+            }
+        } catch (SQLException e) {
+            throw new PersistenceException(
+                    "Something went wrong while reading transaction summary from SQLite", e);
+        }
+
+        String logString = sb.toString();
+        LOGGER.info(logString);
+    }
+
+    @Override
+    public void clearTXData() {
+        flushTable("transactions");
+    }
+
+    @Override
+    public void clearOfferData() {
+        flushTable("offers");
+    }
+
+    @Override
+    public void clearProductData() {
+        flushTable("products");
+    }
+
+    /**
+     * Flushes all data from the specified table.
+     *
+     * @param table
+     */
+    private void flushTable(final String table) {
+        try (Connection connection = db.getConnection();
+                Statement statement = connection.createStatement()) {
+            if (table.matches("[\\w]+")) {
+                String query = "DELETE FROM " + table + ";";
+                statement.executeUpdate(query);
+            } else {
+                throw new PersistenceException("Table name contains illegal characters");
+            }
+        } catch (SQLException e) {
+            throw new PersistenceException("Something went wrong while clearing the database", e);
+        }
+    }
+
+    @Override
+    public void deleteOfferById(final String offerId) {
+        String query = "DELETE FROM offers WHERE offerID = ?;";
+
+        try (Connection connection = db.getConnection();
+                PreparedStatement statement = connection.prepareStatement(query)) {
+            statement.setString(1, offerId);
+
+            statement.executeUpdate();
+        } catch (SQLException e) {
+            throw new PersistenceException(
+                    "Something went wrong while deleting offer from SQLite", e);
+        }
+    }
+
+    @Override
+    public List<OfferDTO> getOffers() {
+        List<OfferDTO> list = new ArrayList<>();
+        String query = "SELECT * FROM offers";
+
+        try (Connection connection = db.getConnection();
+                PreparedStatement statement = connection.prepareStatement(query)) {
+
+            try (ResultSet resultSet = statement.executeQuery()) {
+                while (resultSet.next()) {
+                    OfferDTO dto = new OfferDTO();
+                    ProductDTO srcProduct = getProductDTOById(resultSet.getString("sourceId"));
+                    ProductDTO targetProduct = getProductDTOById(resultSet.getString("targetId"));
+                    dto.setOfferId(resultSet.getString(OFFERID_COL_NAME));
+                    dto.setSourceProduct(srcProduct);
+                    dto.setTargetProduct(targetProduct);
+                    dto.setLastUpdate(resultSet.getString(LAST_UPDATE_COL_NAME));
+
+                    list.add(dto);
+                }
+            }
+        } catch (SQLException e) {
+            throw new PersistenceException(
+                    "Something went wrong while reading offers from SQLite", e);
+        }
+
+        return list;
+    }
 }

src/main/java/de/rwu/easydrop/data/connector/TransactionPersistenceInterface.java

@@ -0,0 +1,32 @@
+package de.rwu.easydrop.data.connector;
+
+import de.rwu.easydrop.api.dto.TransactionDTO;
+
+/**
+ * Persistence interface for transactions.
+ *
+ * @since 0.3.0
+ */
+public interface TransactionPersistenceInterface {
+    /**
+     * Writes a ProductDTO to persistence.
+     *
+     * @param dto
+     */
+    void writeTX(TransactionDTO dto);
+
+    /**
+     * Writes transactions to log.
+     */
+    void outputTransactionsToLog();
+
+    /**
+     * Writes transaction summary (total volume and earnings) to log.
+     */
+    void outputSummaryToLog();
+
+    /**
+     * Deletes all transaction data from persistence.
+     */
+    void clearTXData();
+}

src/main/java/de/rwu/easydrop/exception/InvalidOfferException.java

@@ -1,5 +1,10 @@
 package de.rwu.easydrop.exception;
 
+/**
+ * Exception that signifies the data of an Offer are invalid.
+ *
+ * @since 0.3.0
+ */
 public class InvalidOfferException extends RuntimeException {
     /**
      * Throws an exception that signifies the data of an Offer are invalid.

src/main/java/de/rwu/easydrop/exception/InvalidTransactionException.java

@@ -0,0 +1,27 @@
+package de.rwu.easydrop.exception;
+
+/**
+ * Exception that signifies the data of a Transaction are invalid.
+ *
+ * @since 0.3.0
+ */
+public class InvalidTransactionException extends RuntimeException {
+    /**
+     * Throws an exception that signifies the data of an Offer are invalid.
+     *
+     * @param message
+     */
+    public InvalidTransactionException(final String message) {
+        super(message);
+    }
+
+    /**
+     * Throws an exception that signifies the data of an Offer are invalid.
+     *
+     * @param message
+     * @param cause
+     */
+    public InvalidTransactionException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+}

src/main/java/de/rwu/easydrop/service/processing/TransactionHandler.java

@@ -0,0 +1,47 @@
+package de.rwu.easydrop.service.processing;
+
+import de.rwu.easydrop.api.dto.TransactionDTO;
+import de.rwu.easydrop.data.connector.TransactionPersistenceInterface;
+import de.rwu.easydrop.model.Offer;
+import de.rwu.easydrop.model.Transaction;
+import de.rwu.easydrop.service.mapping.TransactionMapper;
+import de.rwu.easydrop.util.Timestamp;
+
+/**
+ * Handles transactions.
+ *
+ * @since 0.3.0
+ */
+public class TransactionHandler {
+    /**
+     * Transaction persistence.
+     */
+    private TransactionPersistenceInterface txPersistence;
+
+    /**
+     * Creates new transaction handler.
+     *
+     * @param txdb transaction persistence
+     */
+    public TransactionHandler(final TransactionPersistenceInterface txdb) {
+        this.txPersistence = txdb;
+    }
+
+    /**
+     * Creates transaction from offer.
+     *
+     * @param offer Offer
+     */
+    public void turnOfferToTransaction(final Offer offer) {
+        Transaction tx = new Transaction();
+        tx.setOfferId(offer.getOfferId());
+        tx.setVolume(offer.getTargetProduct().getCurrentPrice());
+        tx.setEarnings(offer.getTargetProduct().getCurrentPrice()
+                - offer.getSourceProduct().getCurrentPrice());
+        tx.setTransactionTime(Timestamp.now());
+
+        // Write transaction to persistence
+        TransactionDTO txDTO = TransactionMapper.mapTXToDTO(tx);
+        txPersistence.writeTX(txDTO);
+    }
+}

src/main/java/de/rwu/easydrop/service/validation/TransactionValidator.java

@@ -0,0 +1,42 @@
+package de.rwu.easydrop.service.validation;
+
+import de.rwu.easydrop.exception.InvalidTransactionException;
+import de.rwu.easydrop.model.Transaction;
+
+/**
+ * Validates transactions.
+ *
+ * @since 0.3.0
+ */
+public final class TransactionValidator {
+    /**
+     * Private constructor to prevent unwanted instantiation.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    private TransactionValidator() throws UnsupportedOperationException {
+        throw new UnsupportedOperationException("This is a validator class, don't instantiate it.");
+    }
+
+    /**
+     * Makes sure a transaction does not contain invalid information.
+     *
+     * @param tx the Transaction
+     */
+    public static void validate(final Transaction tx) {
+        try {
+            if (tx.getOfferId().equals("")) {
+                throw new InvalidTransactionException("Offer ID cannot be empty");
+            }
+            if (tx.getEarnings() == 0) {
+                throw new InvalidTransactionException("Earnings can't be zero");
+            }
+            if (tx.getVolume() == 0) {
+                throw new InvalidTransactionException("Volume can't be zero");
+            }
+        } catch (NullPointerException e) {
+            throw new InvalidTransactionException(
+                    "Required information is missing in the transaction", e);
+        }
+    }
+}

src/main/java/de/rwu/easydrop/service/writer/TransactionWriter.java

@@ -0,0 +1,33 @@
+package de.rwu.easydrop.service.writer;
+
+import de.rwu.easydrop.api.dto.TransactionDTO;
+import de.rwu.easydrop.data.connector.TransactionPersistenceInterface;
+import de.rwu.easydrop.model.Transaction;
+import de.rwu.easydrop.service.mapping.TransactionMapper;
+import de.rwu.easydrop.service.validation.TransactionValidator;
+
+public class TransactionWriter {
+    /**
+     * Persistence.
+     */
+    private TransactionPersistenceInterface persistence;
+
+    /**
+     * @param newPersistence the persistence to set
+     */
+    public TransactionWriter(final TransactionPersistenceInterface newPersistence) {
+        this.persistence = newPersistence;
+    }
+
+    /**
+     * Validates and saves a transaction to persistence.
+     *
+     * @param tx Transaction
+     */
+    public void writeTXToPersistence(final Transaction tx) {
+        TransactionDTO dto = TransactionMapper.mapTXToDTO(tx);
+        TransactionValidator.validate(tx);
+
+        persistence.writeTX(dto);
+    }
+}