[401763] Make CDO Server more robust against data dictionary changes

https://bugs.eclipse.org/bugs/show_bug.cgi?id=401763

1 files changed, 122 insertions, 0 deletions

diff --git a/plugins/org.eclipse.net4j.db/src/org/eclipse/net4j/internal/db/DBTransaction.java b/plugins/org.eclipse.net4j.db/src/org/eclipse/net4j/internal/db/DBTransaction.java
new file mode 100644
index 0000000000..caa45f135b
--- /dev/null
+++ b/plugins/org.eclipse.net4j.db/src/org/eclipse/net4j/internal/db/DBTransaction.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2004 - 2012 Eike Stepper (Berlin, Germany) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ */
+package org.eclipse.net4j.internal.db;
+
+import org.eclipse.net4j.db.DBException;
+import org.eclipse.net4j.db.DBUtil;
+import org.eclipse.net4j.db.IDBTransaction;
+import org.eclipse.net4j.db.IDBPreparedStatement;
+import org.eclipse.net4j.db.IDBPreparedStatement.ReuseProbability;
+import org.eclipse.net4j.db.IDBSchemaTransaction;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.util.HashSet;
+import java.util.NavigableMap;
+import java.util.Set;
+import java.util.TreeMap;
+
+/**
+ * @author Eike Stepper
+ */
+public final class DBTransaction extends DBElement implements IDBTransaction
+{
+  private final DBDatabase database;
+
+  private final NavigableMap<String, DBPreparedStatement> cache = new TreeMap<String, DBPreparedStatement>();
+
+  private final Set<DBPreparedStatement> checkOuts = new HashSet<DBPreparedStatement>();
+
+  private int lastTouch;
+
+  private Connection connection;
+
+  public DBTransaction(DBDatabase database)
+  {
+    this.database = database;
+    connection = database.getConnectionProvider().getConnection();
+  }
+
+  public DBDatabase getDatabase()
+  {
+    return database;
+  }
+
+  public void close()
+  {
+    DBUtil.close(connection);
+    connection = null;
+
+    database.closeTransaction(this);
+  }
+
+  public boolean isClosed()
+  {
+    return connection != null;
+  }
+
+  public Connection getConnection()
+  {
+    return connection;
+  }
+
+  public IDBPreparedStatement getPreparedStatement(String sql, ReuseProbability reuseProbability)
+  {
+    DBPreparedStatement preparedStatement = cache.remove(sql);
+    if (preparedStatement == null)
+    {
+      try
+      {
+        PreparedStatement delegate = connection.prepareStatement(sql);
+        preparedStatement = new DBPreparedStatement(this, sql, reuseProbability, delegate);
+      }
+      catch (SQLException ex)
+      {
+        throw new DBException(ex);
+      }
+    }
+
+    checkOuts.add(preparedStatement);
+    return preparedStatement;
+  }
+
+  public void releasePreparedStatement(DBPreparedStatement preparedStatement)
+  {
+    if (preparedStatement == null)
+    {
+      // Bug 276926: Silently accept preparedStatement == null and do nothing.
+      return;
+    }
+
+    checkOuts.remove(preparedStatement);
+    preparedStatement.setTouch(++lastTouch);
+
+    String sql = preparedStatement.getSQL();
+    if (cache.put(sql, preparedStatement) != null)
+    {
+      throw new IllegalStateException(sql + " already in cache"); //$NON-NLS-1$
+    }
+
+    if (cache.size() > database.getStatementCacheCapacity())
+    {
+      DBPreparedStatement old = cache.remove(cache.firstKey());
+      DBUtil.close(old.getDelegate());
+    }
+  }
+
+  public IDBSchemaTransaction openSchemaTransaction()
+  {
+    DBSchemaTransaction schemaTransaction = database.openSchemaTransaction();
+    schemaTransaction.setTransaction(this);
+    return schemaTransaction;
+  }
+}