public class DatabaseConnection {
- public static final int CURRENT_SCHEMA_VERSION = 6;
+ public static final int MAX_CACHED_INSTANCES = 3;
+
+ private static class StatementDescriptor {
+
+ String query;
+
+ boolean scrollable;
+
+ int instance;
+
+ PreparedStatement target;
+
+ public StatementDescriptor(String query, boolean scrollable) {
+ this.query = query;
+ this.scrollable = scrollable;
+ this.instance = 0;
+ }
+
+ public synchronized void instanciate(Connection c) throws SQLException {
+ if (scrollable) {
+ target = c.prepareStatement(query, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
+ } else {
+ target = c.prepareStatement(query, query.startsWith("SELECT ") ? Statement.NO_GENERATED_KEYS : Statement.RETURN_GENERATED_KEYS);
+ }
+
+ }
+
+ public synchronized PreparedStatement getTarget() {
+ return target;
+ }
+
+ public synchronized void increase() {
+ if (target != null) {
+ throw new IllegalStateException();
+ }
+ instance++;
+ }
+
+ @Override
+ public int hashCode() {
+ final int prime = 31;
+ int result = 1;
+ result = prime * result + instance;
+ result = prime * result + ((query == null) ? 0 : query.hashCode());
+ result = prime * result + (scrollable ? 1231 : 1237);
+ return result;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) {
+ return true;
+ }
+ if (obj == null) {
+ return false;
+ }
+ if (getClass() != obj.getClass()) {
+ return false;
+ }
+ StatementDescriptor other = (StatementDescriptor) obj;
+ if (instance != other.instance) {
+ return false;
+ }
+ if (query == null) {
+ if (other.query != null) {
+ return false;
+ }
+ } else if ( !query.equals(other.query)) {
+ return false;
+ }
+ if (scrollable != other.scrollable) {
+ return false;
+ }
+ return true;
+ }
+
+ }
+
+ public static final int CURRENT_SCHEMA_VERSION = 11;
public static final int CONNECTION_TIMEOUT = 24 * 60 * 60;
private Connection c;
- private HashMap<String, PreparedStatement> statements = new HashMap<String, PreparedStatement>();
+ private HashMap<StatementDescriptor, PreparedStatement> statements = new HashMap<StatementDescriptor, PreparedStatement>();
HashSet<PreparedStatement> underUse = new HashSet<>();
}
protected synchronized PreparedStatement prepareInternal(String query) throws SQLException {
+ return prepareInternal(query, false);
+ }
+
+ protected synchronized PreparedStatement prepareInternal(String query, boolean scrollable) throws SQLException {
+
ensureOpen();
query = preprocessQuery(query);
- PreparedStatement statement = statements.get(query);
- if (statement != null) {
- if (underUse.add(statement)) {
- return statement;
+ StatementDescriptor searchHead = new StatementDescriptor(query, scrollable);
+ PreparedStatement statement = null;
+ while (statement == null) {
+ statement = statements.get(searchHead);
+ if (statement == null) {
+ searchHead.instanciate(c);
+ statement = searchHead.getTarget();
+ if (searchHead.instance >= MAX_CACHED_INSTANCES) {
+ return statement;
+ }
+ underUse.add(statement);
+ statements.put(searchHead, statement);
+ } else if (underUse.contains(statement)) {
+ searchHead.increase();
+ statement = null;
} else {
- throw new Error("Statement in Use");
+ underUse.add(statement);
}
}
- statement = c.prepareStatement(query, query.startsWith("SELECT ") ? Statement.NO_GENERATED_KEYS : Statement.RETURN_GENERATED_KEYS);
- statements.put(query, statement);
- if (underUse.add(statement)) {
- return statement;
- } else {
- throw new Error("Statement in Use");
- }
+ return statement;
}
protected synchronized PreparedStatement prepareInternalScrollable(String query) throws SQLException {
- ensureOpen();
- query = preprocessQuery(query);
- PreparedStatement statement = statements.get("__SCROLLABLE__! " + query);
- if (statement != null) {
- if (underUse.add(statement)) {
- return statement;
- } else {
- throw new Error("Statement in Use");
- }
- }
- statement = c.prepareStatement(query, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
- statements.put("__SCROLLABLE__! " + query, statement);
- if (underUse.add(statement)) {
- return statement;
- } else {
- throw new Error("Statement in Use");
- }
+ return prepareInternal(query, true);
}
private long lastAction = System.currentTimeMillis();
lastAction = System.currentTimeMillis();
}
- private static DatabaseConnection instance;
+ private static volatile DatabaseConnection instance;
- public static DatabaseConnection getInstance() {
+ public static synchronized DatabaseConnection getInstance() {
if (instance == null) {
- synchronized (DatabaseConnection.class) {
- if (instance == null) {
- instance = new DatabaseConnection();
- }
- }
+ instance = new DatabaseConnection();
}
return instance;
}
upgrade(version);
}
- public void beginTransaction() throws SQLException {
- c.setAutoCommit(false);
- }
-
private static void upgrade(int version) {
try {
Statement s = getInstance().c.createStatement();
try {
while (version < CURRENT_SCHEMA_VERSION) {
- try (InputStream resourceAsStream = DatabaseConnection.class.getResourceAsStream("upgrade/from_" + version + ".sql")) {
- if (resourceAsStream == null) {
- throw new Error("Upgrade script from version " + version + " was not found.");
- }
- SQLFileManager.addFile(s, resourceAsStream, ImportType.PRODUCTION);
- }
+ addUpgradeScript(Integer.toString(version), s);
version++;
}
s.addBatch("UPDATE \"schemeVersion\" SET version='" + version + "'");
}
}
- public void commitTransaction() throws SQLException {
- c.commit();
- c.setAutoCommit(true);
- }
-
- public void quitTransaction() {
- try {
- if ( !c.getAutoCommit()) {
- c.rollback();
- c.setAutoCommit(true);
+ private static void addUpgradeScript(String version, Statement s) throws Error, IOException, SQLException {
+ try (InputStream resourceAsStream = DatabaseConnection.class.getResourceAsStream("upgrade/from_" + version + ".sql")) {
+ if (resourceAsStream == null) {
+ throw new Error("Upgrade script from version " + version + " was not found.");
}
- } catch (SQLException e) {
- e.printStackTrace();
+ SQLFileManager.addFile(s, resourceAsStream, ImportType.PRODUCTION);
}
}
return ident;
}
- protected synchronized void returnStatement(PreparedStatement target) {
- underUse.remove(target);
+ protected synchronized void returnStatement(PreparedStatement target) throws SQLException {
+ if ( !underUse.remove(target)) {
+ target.close();
+ }
+ }
+
+ public synchronized int getNumberOfLockedStatements() {
+ return underUse.size();
}
- public void lockedStatements(PrintWriter writer) {
+ public synchronized void lockedStatements(PrintWriter writer) {
writer.println(underUse.size());
for (PreparedStatement ps : underUse) {
- for (Entry<String, PreparedStatement> e : statements.entrySet()) {
+ for (Entry<StatementDescriptor, PreparedStatement> e : statements.entrySet()) {
if (e.getValue() == ps) {
writer.println("<br/>");
- writer.println(e.getKey());
+ writer.println(e.getKey().instance + ":");
+
+ writer.println(e.getKey().query);
}
}
}
projects / gigi.git / blobdiff