ccache2.java

Java示例100

/**
 *  JDBC 2.0 Spec doesn't mandate that JDBC vendors implement a
 *  Connection Cache. However, we implemented a basic one with 2
 *  schemes as an Example.
 *
 *  There are 3 cache schemes: DYNAMIC_SCHEME (default)
 *                             FIXED_RETURN_NULL_SCHEME
 *                             FIXED_WAIT_SCHEME
 *
 *  A Sample demo to illustrate FIXED_RETURN_NULL_SCHEME of 
 *  OracleConnectionCacheImpl.
 *  Fixed with NoWait :  At no instance there will be no  more active 
 *  connections than the  the Maximum limit. Request for new connections 
 *  beyond the max limit will return null.
 *  Please compare with CCache1.java and CCache3.java 
 *  Please use jdk1.2 or later version
 */

// You need to import the java.sql package to use JDBC
import java.sql.*;
import javax.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.*;

public class CCache2 {

  public static void main (String args [])
       throws SQLException
  {
    String url = "jdbc:oracle:oci8:@";
    try {
      String url1 = System.getProperty("JDBC_URL");
      if (url1 != null)
        url = url1;
    } catch (Exception e) {
      // If there is any security exception, ignore it
      // and use the default
    }

    // Create a OracleConnectionPoolDataSource as an factory
    // of PooledConnections for the Cache to create.
    OracleConnectionPoolDataSource ocpds =
                               new OracleConnectionPoolDataSource();
    ocpds.setURL(url);
    ocpds.setUser("hr");
    ocpds.setPassword("hr");

    // Associate it with the Cache
    OracleConnectionCacheImpl ods = new OracleConnectionCacheImpl(ocpds);

    // Set the Max Limit
    ods.setMaxLimit (3);

    // Set the Scheme
    ods.setCacheScheme (OracleConnectionCacheImpl.FIXED_RETURN_NULL_SCHEME);

    Connection conn = null;
    for (int i=0; i < 5; ++i )
    {
      conn = ods.getConnection();
      if (conn != null)
        System.out.println("Connection " + i + " Succeeded!");
      else
        System.out.println("Connection " + i + " Failed !!!");
    }

    System.out.println("Active size : " + ods.getActiveSize());
    System.out.println("Cache Size is " + ods.getCacheSize());

    // close the Data Source
    ods.close();

    System.out.println("Active size : " + ods.getActiveSize());
    System.out.println("Cache Size is " + ods.getCacheSize());

  }
}