Object pool Mode

1. The object pool technology does not limit that only one object can be created, and this technology also applies to creating a fixed number of objects. However, in this case, you have to face the problem of sharing objects in the object pool.

When you create multiple objects at a high cost, you can consider using the object pool technology. The existing technologies include thread pool technology and database connection pool technology.

2. UML diagram (astah/Jude ):

 

3. simulate a database connection pool for implementation:

Implemented interface:

1 package COM. xinye. test. pool; 2/** 3 * all things the user needs implement this interface 4 * @ author Xinye 5*6 */7 public interface iconnection {8 object get (); 9 void set (Object OBJ); 10}

Implementation class:

1 package COM. xinye. test. pool; 2/** 3 * What the user really needs, for example, database connection 4 * @ author Xinye 5*6 */7 public class connection implements iconnection {8 9 @ override10 public object get () {11 // todo auto-generated method stub12 return NULL; 13} 14 15 @ override16 public void set (Object OBJ) {17 // todo auto-generated method stub18 19} 20 21}

Implementation class packaging object (add status ):

1 package COM. xinye. test. pool; 2/** 3 * items in the pool (items with status and what the user actually needs are actually package items) 4 * @ author Xinye 5*6 */7 public class poolitem {8 Public Boolean isuse; 9 Public iconnection conn; 10 public poolitem (iconnection conn) {11 this. conn = conn; 12} 13}

Pooled management objects:

1 package COM. xinye. test. pool; 2 3 Import Java. util. arraylist; 4/** 5 * Pool sub-management class 6 * @ author wangheng 7*8 */9 public class poolmanager {10 11 private arraylist <poolitem> items = new arraylist <poolitem> (); 12/** 13 * put things in the pool 14 * @ Param conn15 */16 public synchronized void add (iconnection conn) {17 items. add (New poolitem (conn); 18} 19/** 20 * Get the object 21 * @ return22 * @ throws poolemptyexception23 */24 public synchronized iconnection get () in the pool () throws poolemptyexception {25 int Len = items. size (); 26 for (INT I = 0; I <Len; I ++) {27 poolitem item = items. get (I); 28 If (item. isuse = false) {29 item. isuse = true; 30 return item. conn; 31} 32} 33 throw new poolemptyexception (); 34} 35/** 36 * release object 37 * @ Param conn38 * @ throws poolemptyexception39 */40 public synchronized void release (iconnection conn) throws poolemptyexception {41 int Len = items. size (); 42 for (INT I = 0; I <Len; I ++) {43 poolitem item = items. get (I); 44 If (conn = item. conn) {45 item. isuse = false; 46 return; 47} 48} 49 throw new poolemptyexception (); 50} 51/** 52 * The pool is empty. Exception 53 * @ author wangheng54 * 55 */56 public static class poolemptyexception extends exception {57/** 58*59 */60 private Static final long serialversionuid = 5617927009406425965l; 61 62} 63 64}

Connection Pool object:

1 package COM. xinye. test. pool; 2 3 Import COM. xinye. test. pool. poolmanager. poolemptyexception; 4 5/** 6 * users who really need to care about the pool 7 * @ author Xinye 8*9 */10 public class connectionpool {11 Private Static poolmanager manager = new poolmanager (); 12/** 13 * Add connection objects in batches 14 * @ Param count15 */16 public static void addconnections (INT count) {17 for (INT I = 0; I <count; I ++) {18 manager. add (New Connection (); 19} 20} 21/** 22 * Get the connection object 23 * @ return24 * @ throws poolemptyexception25 */26 public static iconnection getconnection () throws poolemptyexception {27 return manager. get (); 28} 29/** 30 * release link 31 * @ Param conn32 * @ throws poolemptyexception33 */34 public static void release (iconnection conn) throws poolemptyexception {35 manager. release (conn); 36} 37}