Author: oheger
Date: Mon Apr 8 19:57:35 2013
New Revision: 1465754
URL: http://svn.apache.org/r1465754
Log:
Reworked DatabaseConfiguration.
A template approach is now used for executing SQL operations. This
reduces code duplication.
Modified:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/DatabaseConfiguration.java
commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/TestDatabaseConfiguration.java
Modified:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/DatabaseConfiguration.java
URL:
http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/DatabaseConfiguration.java?rev=1465754&r1=1465753&r2=1465754&view=diff
==============================================================================
---
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/DatabaseConfiguration.java
(original)
+++
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/DatabaseConfiguration.java
Mon Apr 8 19:57:35 2013
@@ -87,6 +87,21 @@ import org.apache.commons.logging.LogFac
*/
public class DatabaseConfiguration extends AbstractConfiguration
{
+ /** Constant for the statement used by getProperty.*/
+ private static final String SQL_GET_PROPERTY = "SELECT * FROM %s WHERE %s
=?";
+
+ /** Constant for the statement used by isEmpty.*/
+ private static final String SQL_IS_EMPTY = "SELECT count(*) FROM %s WHERE
1 = 1";
+
+ /** Constant for the statement used by clearProperty.*/
+ private static final String SQL_CLEAR_PROPERTY = "DELETE FROM %s WHERE %s
=?";
+
+ /** Constant for the statement used by clear.*/
+ private static final String SQL_CLEAR = "DELETE FROM %s WHERE 1 = 1";
+
+ /** Constant for the statement used by getKeys.*/
+ private static final String SQL_GET_KEYS = "SELECT DISTINCT %s FROM %s
WHERE 1 = 1";
+
/** The datasource to connect to the database. */
private final DataSource datasource;
@@ -204,71 +219,47 @@ public class DatabaseConfiguration exten
* @param key the key of the desired property
* @return the value of this property
*/
- public Object getProperty(String key)
+ public Object getProperty(final String key)
{
- Object result = null;
-
- // build the query
- StringBuilder query = new StringBuilder("SELECT * FROM ");
- query.append(table).append(" WHERE ");
- query.append(keyColumn).append("=?");
- if (nameColumn != null)
+ JdbcOperation<Object> op = new
JdbcOperation<Object>(EVENT_READ_PROPERTY, key, null)
{
- query.append(" AND " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
- ResultSet rs = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- pstmt.setString(1, key);
- if (nameColumn != null)
+ @Override
+ protected Object performOperation() throws SQLException
{
- pstmt.setString(2, name);
- }
+ ResultSet rs = openResultSet(String.format(
+ SQL_GET_PROPERTY, table, keyColumn), true, key);
- rs = pstmt.executeQuery();
+ List<Object> results = new ArrayList<Object>();
+ while (rs.next())
+ {
+ Object value = rs.getObject(valueColumn);
+ if (isDelimiterParsingDisabled())
+ {
+ results.add(value);
+ }
+ else
+ {
+ // Split value if it contains the list delimiter
+ Iterator<?> it = PropertyConverter.toIterator(value,
getListDelimiter());
+ while (it.hasNext())
+ {
+ results.add(it.next());
+ }
+ }
+ }
- List<Object> results = new ArrayList<Object>();
- while (rs.next())
- {
- Object value = rs.getObject(valueColumn);
- if (isDelimiterParsingDisabled())
+ if (!results.isEmpty())
{
- results.add(value);
+ return (results.size() > 1) ? results : results.get(0);
}
else
{
- // Split value if it contains the list delimiter
- Iterator<?> it = PropertyConverter.toIterator(value,
getListDelimiter());
- while (it.hasNext())
- {
- results.add(it.next());
- }
+ return null;
}
}
+ };
- if (!results.isEmpty())
- {
- result = (results.size() > 1) ? results : results.get(0);
- }
- }
- catch (SQLException e)
- {
- fireError(EVENT_READ_PROPERTY, key, null, e);
- }
- finally
- {
- close(conn, pstmt, rs);
- }
-
- return result;
+ return op.execute();
}
/**
@@ -282,48 +273,39 @@ public class DatabaseConfiguration exten
* @param obj the value of the property to add
*/
@Override
- protected void addPropertyDirect(String key, Object obj)
+ protected void addPropertyDirect(final String key, final Object obj)
{
- // build the query
- StringBuilder query = new StringBuilder("INSERT INTO " + table);
- if (nameColumn != null)
- {
- query.append(" (" + nameColumn + ", " + keyColumn + ", " +
valueColumn + ") VALUES (?, ?, ?)");
- }
- else
+ new JdbcOperation<Void>(EVENT_ADD_PROPERTY, key, obj)
{
- query.append(" (" + keyColumn + ", " + valueColumn + ") VALUES (?,
?)");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
+ @Override
+ protected Void performOperation() throws SQLException
+ {
+ StringBuilder query = new StringBuilder("INSERT INTO ");
+ query.append(table).append(" (");
+ query.append(keyColumn).append(", ");
+ query.append(valueColumn);
+ if (nameColumn != null)
+ {
+ query.append(", ").append(nameColumn);
+ }
+ query.append(") VALUES (?, ?");
+ if (nameColumn != null)
+ {
+ query.append(", ?");
+ }
+ query.append(")");
- try
- {
- conn = getConnection();
+ PreparedStatement pstmt = initStatement(query.toString(),
+ false, key, String.valueOf(obj));
+ if (nameColumn != null)
+ {
+ pstmt.setString(3, name);
+ }
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- int index = 1;
- if (nameColumn != null)
- {
- pstmt.setString(index++, name);
+ pstmt.executeUpdate();
+ return null;
}
- pstmt.setString(index++, key);
- pstmt.setString(index++, String.valueOf(obj));
-
- pstmt.executeUpdate();
- commitIfRequired(conn);
- }
- catch (SQLException e)
- {
- fireError(EVENT_ADD_PROPERTY, key, obj, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, null);
- }
+ }.execute();
}
/**
@@ -367,48 +349,21 @@ public class DatabaseConfiguration exten
*/
public boolean isEmpty()
{
- boolean empty = true;
- // build the query
- StringBuilder query = new StringBuilder("SELECT count(*) FROM " +
table);
- if (nameColumn != null)
+ JdbcOperation<Integer> op = new
JdbcOperation<Integer>(EVENT_READ_PROPERTY, null, null)
{
- query.append(" WHERE " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
- ResultSet rs = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- if (nameColumn != null)
+ @Override
+ protected Integer performOperation() throws SQLException
{
- pstmt.setString(1, name);
- }
-
- rs = pstmt.executeQuery();
+ ResultSet rs = openResultSet(String.format(
+ SQL_IS_EMPTY, table), true);
- if (rs.next())
- {
- empty = rs.getInt(1) == 0;
+ return rs.next() ? Integer.valueOf(rs.getInt(1)) : null;
}
- }
- catch (SQLException e)
- {
- fireError(EVENT_READ_PROPERTY, null, null, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, rs);
- }
+ };
- return empty;
+ Integer count = op.execute();
+ return count == null || count.intValue() == 0;
}
/**
@@ -421,48 +376,23 @@ public class DatabaseConfiguration exten
* @param key the key to be checked
* @return a flag whether this key is defined
*/
- public boolean containsKey(String key)
+ public boolean containsKey(final String key)
{
- boolean found = false;
-
- // build the query
- StringBuilder query = new StringBuilder("SELECT * FROM " + table + "
WHERE " + keyColumn + "=?");
- if (nameColumn != null)
+ JdbcOperation<Boolean> op = new
JdbcOperation<Boolean>(EVENT_READ_PROPERTY, key, null)
{
- query.append(" AND " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
- ResultSet rs = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- pstmt.setString(1, key);
- if (nameColumn != null)
+ @Override
+ protected Boolean performOperation() throws SQLException
{
- pstmt.setString(2, name);
- }
-
- rs = pstmt.executeQuery();
+ PreparedStatement pstmt = initStatement(String.format(
+ SQL_GET_PROPERTY, table, keyColumn), true, key);
+ ResultSet rs = pstmt.executeQuery();
- found = rs.next();
- }
- catch (SQLException e)
- {
- fireError(EVENT_READ_PROPERTY, key, null, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, rs);
- }
+ return rs.next();
+ }
+ };
- return found;
+ Boolean result = op.execute();
+ return result != null && result.booleanValue();
}
/**
@@ -475,42 +405,19 @@ public class DatabaseConfiguration exten
* @param key the key of the property to be removed
*/
@Override
- protected void clearPropertyDirect(String key)
+ protected void clearPropertyDirect(final String key)
{
- // build the query
- StringBuilder query = new StringBuilder("DELETE FROM " + table + "
WHERE " + keyColumn + "=?");
- if (nameColumn != null)
+ new JdbcOperation<Void>(EVENT_CLEAR_PROPERTY, key, null)
{
- query.append(" AND " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- pstmt.setString(1, key);
- if (nameColumn != null)
+ @Override
+ protected Void performOperation() throws SQLException
{
- pstmt.setString(2, name);
+ PreparedStatement ps = initStatement(String.format(
+ SQL_CLEAR_PROPERTY, table, keyColumn), true, key);
+ ps.executeUpdate();
+ return null;
}
-
- pstmt.executeUpdate();
- commitIfRequired(conn);
- }
- catch (SQLException e)
- {
- fireError(EVENT_CLEAR_PROPERTY, key, null, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, null);
- }
+ }.execute();
}
/**
@@ -524,39 +431,16 @@ public class DatabaseConfiguration exten
public void clear()
{
fireEvent(EVENT_CLEAR, null, null, true);
- // build the query
- StringBuilder query = new StringBuilder("DELETE FROM " + table);
- if (nameColumn != null)
+ new JdbcOperation<Void>(EVENT_CLEAR, null, null)
{
- query.append(" WHERE " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- if (nameColumn != null)
+ @Override
+ protected Void performOperation() throws SQLException
{
- pstmt.setString(1, name);
+ initStatement(String.format(SQL_CLEAR,
+ table), true).executeUpdate();
+ return null;
}
-
- pstmt.executeUpdate();
- commitIfRequired(conn);
- }
- catch (SQLException e)
- {
- fireError(EVENT_CLEAR, null, null, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, null);
- }
+ }.execute();
fireEvent(EVENT_CLEAR, null, null, false);
}
@@ -572,46 +456,22 @@ public class DatabaseConfiguration exten
*/
public Iterator<String> getKeys()
{
- Collection<String> keys = new ArrayList<String>();
-
- // build the query
- StringBuilder query = new StringBuilder("SELECT DISTINCT " + keyColumn
+ " FROM " + table);
- if (nameColumn != null)
+ final Collection<String> keys = new ArrayList<String>();
+ new JdbcOperation<Collection<String>>(EVENT_READ_PROPERTY, null, null)
{
- query.append(" WHERE " + nameColumn + "=?");
- }
-
- Connection conn = null;
- PreparedStatement pstmt = null;
- ResultSet rs = null;
-
- try
- {
- conn = getConnection();
-
- // bind the parameters
- pstmt = conn.prepareStatement(query.toString());
- if (nameColumn != null)
+ @Override
+ protected Collection<String> performOperation() throws SQLException
{
- pstmt.setString(1, name);
- }
-
- rs = pstmt.executeQuery();
+ ResultSet rs = openResultSet(String.format(
+ SQL_GET_KEYS, keyColumn, table), true);
- while (rs.next())
- {
- keys.add(rs.getString(1));
+ while (rs.next())
+ {
+ keys.add(rs.getString(1));
+ }
+ return keys;
}
- }
- catch (SQLException e)
- {
- fireError(EVENT_READ_PROPERTY, null, null, e);
- }
- finally
- {
- // clean up
- close(conn, pstmt, rs);
- }
+ }.execute();
return keys.iterator();
}
@@ -628,23 +488,6 @@ public class DatabaseConfiguration exten
}
/**
- * Returns a {@code Connection} object. This method is called when
- * ever the database is to be accessed. This implementation returns a
- * connection from the current {@code DataSource}.
- *
- * @return the {@code Connection} object to be used
- * @throws SQLException if an error occurs
- * @since 1.4
- * @deprecated Use a custom data source to change the connection used by
the
- * class. To be removed in Commons Configuration 2.0
- */
- @Deprecated
- protected Connection getConnection() throws SQLException
- {
- return getDatasource().getConnection();
- }
-
- /**
* Close the specified database objects.
* Avoid closing if null and hide any SQLExceptions that occur.
*
@@ -692,18 +535,180 @@ public class DatabaseConfiguration exten
}
/**
- * Performs a commit if needed. This method is called after updates of the
- * managed database table. If the configuration should perform commits, it
- * does so now.
- *
- * @param conn the active connection
- * @throws SQLException if an error occurs
- */
- private void commitIfRequired(Connection conn) throws SQLException
- {
- if (isDoCommits())
+ * An internally used helper class for simplifying database access through
+ * plain JDBC. This class provides a simple framework for creating and
+ * executing a JDBC statement. It especially takes care of proper handling
+ * of JDBC resources even in case of an error.
+ * @param <T> the type of the results produced by a JDBC operation
+ */
+ private abstract class JdbcOperation<T>
+ {
+ /** Stores the connection. */
+ private Connection conn;
+
+ /** Stores the statement. */
+ private PreparedStatement pstmt;
+
+ /** Stores the result set. */
+ private ResultSet resultSet;
+
+ /** The type of the event to send in case of an error. */
+ private final int errorEventType;
+
+ /** The property name for an error event. */
+ private final String errorPropertyName;
+
+ /** The property value for an error event. */
+ private final Object errorPropertyValue;
+
+ /**
+ * Creates a new instance of {@code JdbcOperation} and initializes
+ * the properties related to the error event.
+ *
+ * @param errEvType the type of the error event
+ * @param errPropName the property name for the error event
+ * @param errPropVal the property value for the error event
+ */
+ protected JdbcOperation(int errEvType, String errPropName,
+ Object errPropVal)
+ {
+ errorEventType = errEvType;
+ errorPropertyName = errPropName;
+ errorPropertyValue = errPropVal;
+ }
+
+ /**
+ * Executes this operation. This method obtains a database connection
+ * and then delegates to {@code performOperation()}. Afterwards it
+ * performs the necessary clean up. Exceptions that are thrown during
+ * the JDBC operation are caught and transformed into configuration
+ * error events.
+ *
+ * @return the result of the operation
+ */
+ public T execute()
+ {
+ T result = null;
+
+ try
+ {
+ conn = getDatasource().getConnection();
+ result = performOperation();
+
+ if (isDoCommits())
+ {
+ conn.commit();
+ }
+ }
+ catch (SQLException e)
+ {
+ fireError(errorEventType, errorPropertyName,
+ errorPropertyValue, e);
+ }
+ finally
+ {
+ close(conn, pstmt, resultSet);
+ }
+
+ return result;
+ }
+
+ /**
+ * Returns the current connection. This method can be called while
+ * {@code execute()} is running. It returns <b>null</b> otherwise.
+ *
+ * @return the current connection
+ */
+ protected Connection getConnection()
+ {
+ return conn;
+ }
+
+ /**
+ * Creates a {@code PreparedStatement} object for executing the
+ * specified SQL statement.
+ *
+ * @param sql the statement to be executed
+ * @param nameCol a flag whether the name column should be taken into
+ * account
+ * @return the prepared statement object
+ * @throws SQLException if an SQL error occurs
+ */
+ protected PreparedStatement createStatement(String sql, boolean
nameCol)
+ throws SQLException
+ {
+ String statement;
+ if (nameCol && nameColumn != null)
+ {
+ StringBuilder buf = new StringBuilder(sql);
+ buf.append(" AND ").append(nameColumn).append("=?");
+ statement = buf.toString();
+ }
+ else
+ {
+ statement = sql;
+ }
+
+ pstmt = getConnection().prepareStatement(statement);
+ return pstmt;
+ }
+
+ /**
+ * Creates an initializes a {@code PreparedStatement} object for
+ * executing an SQL statement. This method first calls
+ * {@code createStatement()} for creating the statement and then
+ * initializes the statement's parameters.
+ *
+ * @param sql the statement to be executed
+ * @param nameCol a flag whether the name column should be taken into
+ * account
+ * @param params the parameters for the statement
+ * @return the initialized statement object
+ * @throws SQLException if an SQL error occurs
+ */
+ protected PreparedStatement initStatement(String sql, boolean nameCol,
+ Object... params) throws SQLException
{
- conn.commit();
+ PreparedStatement ps = createStatement(sql, nameCol);
+
+ int idx = 1;
+ for (Object param : params)
+ {
+ ps.setObject(idx++, param);
+ }
+ if (nameCol && nameColumn != null)
+ {
+ ps.setString(idx, name);
+ }
+
+ return ps;
}
+
+ /**
+ * Creates a {@code PreparedStatement} for a query, initializes it and
+ * executes it. The resulting {@code ResultSet} is returned.
+ *
+ * @param sql the statement to be executed
+ * @param nameCol a flag whether the name column should be taken into
+ * account
+ * @param params the parameters for the statement
+ * @return the {@code ResultSet} produced by the query
+ * @throws SQLException if an SQL error occurs
+ */
+ protected ResultSet openResultSet(String sql, boolean nameCol,
+ Object... params) throws SQLException
+ {
+ return initStatement(sql, nameCol, params).executeQuery();
+ }
+
+ /**
+ * Performs the JDBC operation. This method is called by
+ * {@code execute()} after this object has been fully initialized.
+ * Here the actual JDBC logic has to be placed.
+ *
+ * @return the result of the operation
+ * @throws SQLException if an SQL error occurs
+ */
+ protected abstract T performOperation() throws SQLException;
}
}
Modified:
commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/TestDatabaseConfiguration.java
URL:
http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/TestDatabaseConfiguration.java?rev=1465754&r1=1465753&r2=1465754&view=diff
==============================================================================
---
commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/TestDatabaseConfiguration.java
(original)
+++
commons/proper/configuration/trunk/src/test/java/org/apache/commons/configuration/TestDatabaseConfiguration.java
Mon Apr 8 19:57:35 2013
@@ -21,13 +21,13 @@ import static org.junit.Assert.assertEqu
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
-import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
import javax.sql.DataSource;
+import org.easymock.EasyMock;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
@@ -539,13 +539,25 @@ public class TestDatabaseConfiguration
}
@Override
- protected Connection getConnection() throws SQLException
+ public DataSource getDatasource()
{
if (failOnConnect)
{
- throw new SQLException("Simulated DB error");
+ DataSource ds = EasyMock.createMock(DataSource.class);
+ try
+ {
+ EasyMock.expect(ds.getConnection()).andThrow(
+ new SQLException("Simulated DB error"));
+ }
+ catch (SQLException e)
+ {
+ // should not happen
+ throw new AssertionError("Unexpected exception!");
+ }
+ EasyMock.replay(ds);
+ return ds;
}
- return super.getConnection();
+ return super.getDatasource();
}
}
}
