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   *   Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
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   *
   *    https://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
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  package org.apache.cayenne.datasource;
  
  import java.io.PrintWriter;
  import java.sql.Connection;
  import java.sql.SQLException;
  import java.sql.SQLFeatureNotSupportedException;
  import java.util.logging.Logger;
  
  import javax.sql.DataSource;
  
  import org.apache.cayenne.di.ScopeEventListener;
  
  /**
   * A wrapper for {@link UnmanagedPoolingDataSource} that automatically manages
   * the underlying connection pool size.
   * 
   * @since 4.0
   */
  public class ManagedPoolingDataSource implements PoolingDataSource, ScopeEventListener {
  
  	private final PoolingDataSourceManager dataSourceManager;
  	private DataSource dataSource;
  
  	public ManagedPoolingDataSource(UnmanagedPoolingDataSource dataSource) {
  		// wake every 2 minutes...
  		this(dataSource, 120000);
  	}
  
  	public ManagedPoolingDataSource(UnmanagedPoolingDataSource dataSource, long managerWakeTime) {
  		this.dataSource = dataSource;
  		this.dataSourceManager = new PoolingDataSourceManager(dataSource, managerWakeTime);
  
  		dataSourceManager.start();
  	}
  
  	PoolingDataSourceManager getDataSourceManager() {
  		return dataSourceManager;
  	}
  
  	int poolSize() {
  		return dataSourceManager.getDataSource().poolSize();
  	}
  
  	int availableSize() {
  		return dataSourceManager.getDataSource().availableSize();
  	}
  	
  	int canExpandSize() {
  		return dataSourceManager.getDataSource().canExpandSize();
  	}
  
  	/**
  	 * Calls {@link #close()} to drain the underlying pool, close open
  	 * connections and block the DataSource from creating any new connections.
  	 */
  	@Override
  	public void beforeScopeEnd() {
  		close();
  	}
  
  	@Override
  	public void close() {
  
  		// swap the underlying DataSource to prevent further interaction with
  		// the callers
  		this.dataSource = new StoppedDataSource(dataSource);
  
  		// shut down the thread..
  		this.dataSourceManager.shutdown();
  	}
  
  	@Override
  	public Connection getConnection() throws SQLException {
  		return dataSource.getConnection();
  	}
  
  	@Override
  	public Connection getConnection(String username, String password) throws SQLException {
  		return dataSource.getConnection(username, password);
  	}
  
  	@Override
  	public PrintWriter getLogWriter() throws SQLException {
  		return dataSource.getLogWriter();
  	}
  
  	@Override
  	public int getLoginTimeout() throws SQLException {
  		return dataSource.getLoginTimeout();
  	}
  
  	@Override
  	public boolean isWrapperFor(Class<?> iface) throws SQLException {
  		return ManagedPoolingDataSource.class.equals(iface) || dataSource.isWrapperFor(iface);
  	}
  
  	@Override
  	public void setLogWriter(PrintWriter arg0) throws SQLException {
  		dataSource.setLogWriter(arg0);
  	}
  
  	@Override
  	public void setLoginTimeout(int arg0) throws SQLException {
  		dataSource.setLoginTimeout(arg0);
  	}
  
  	@SuppressWarnings("unchecked")
  	@Override
  	public <T> T unwrap(Class<T> iface) throws SQLException {
  		return ManagedPoolingDataSource.class.equals(iface) ? (T) this : dataSource.unwrap(iface);
  	}
  
  	@Override
  	public Logger getParentLogger() throws SQLFeatureNotSupportedException {
  		return dataSource.getParentLogger();
  	}
  
  }
  