|
1
5 package org.h2.command;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.engine.Constants;
10 import org.h2.engine.Database;
11 import org.h2.engine.Session;
12 import org.h2.message.Message;
13 import org.h2.message.Trace;
14 import org.h2.result.LocalResult;
15 import org.h2.result.ResultInterface;
16 import org.h2.util.ObjectArray;
17
18
21 public abstract class Command implements CommandInterface {
22 protected Session session;
23 protected long startTime;
24 protected Trace trace;
25 private volatile boolean cancel;
26
27 public abstract boolean isTransactional();
28 public abstract boolean isQuery();
29 public abstract ObjectArray getParameters();
30 public abstract boolean isReadOnly();
31
32 public Command(Parser parser) {
33 this.session = parser.getSession();
34 trace = session.getDatabase().getTrace(Trace.COMMAND);
35 }
36
37 public int update() throws SQLException {
38 throw Message.getSQLException(Message.METHOD_NOT_ALLOWED_FOR_QUERY);
39 }
40
41 public LocalResult query(int maxrows) throws SQLException {
42 throw Message.getSQLException(Message.METHOD_ONLY_ALLOWED_FOR_QUERY);
43 }
44
45
60 public ResultInterface executeQuery(int maxrows, boolean scrollable) throws SQLException {
61 return executeQueryLocal(maxrows);
62 }
63
64 public LocalResult executeQueryLocal(int maxrows) throws SQLException {
65 startTime = System.currentTimeMillis();
66 Database database = session.getDatabase();
67 Object sync = Constants.MULTI_THREADED_KERNEL ? (Object )session : (Object )database;
68 synchronized (sync) {
69 try {
70 database.checkPowerOff();
71 session.setCurrentCommand(this);
72 LocalResult result = query(maxrows);
73 return result;
74 } catch(Throwable e) {
75 SQLException s = Message.convert(e);
76 database.exceptionThrown(s);
77 throw s;
78 } finally {
79 stop();
80 }
81 }
82 }
83
84 protected void start() {
85 startTime = System.currentTimeMillis();
86 }
87
88 public void checkCancelled() throws SQLException {
89 if (cancel) {
90 throw Message.getSQLException(Message.STATEMENT_WAS_CANCELLED);
91 }
92 session.throttle();
93 }
94
95 private void stop() throws SQLException {
96 session.setCurrentCommand(null);
97 if (!isTransactional()) {
98 session.commit();
100 } else if (session.getAutoCommit()) {
101 session.commit();
102 }
103 if (trace.info()) {
104 long time = System.currentTimeMillis() - startTime;
105 if (time > Constants.LONG_QUERY_LIMIT_MS) {
106 trace.info("long query: " + time);
107 }
108 }
109 }
110
111 public int executeUpdate() throws SQLException {
112 startTime = System.currentTimeMillis();
113 Database database = session.getDatabase();
114 Object sync = Constants.MULTI_THREADED_KERNEL ? (Object )session : (Object )database;
115 synchronized (sync) {
116 int rollback = session.getLogId();
117 session.setCurrentCommand(this);
118 try {
119 database.checkPowerOff();
120 int result = update();
121 return result;
122 } catch (SQLException e) {
123 database.exceptionThrown(e);
124 database.checkPowerOff();
125 session.rollbackTo(rollback);
126 throw e;
127 } finally {
128 stop();
129 }
130 }
131 }
132
133 public void close() {
134 }
136
137 public void cancel() {
138 this.cancel = true;
139 }
140
141 }
142 |
Popular Tags |
Java API By Example, From Geeks To Geeks.