jdbcpiedataset.html

jfreechart1。0。2的api。

<FONT color="green">156</FONT>         *  The results from the query are extracted and cached locally, thus<a name="line.156"></a>
<FONT color="green">157</FONT>         *  applying an upper limit on how many rows can be retrieved successfully.<a name="line.157"></a>
<FONT color="green">158</FONT>         *<a name="line.158"></a>
<FONT color="green">159</FONT>         * @param  query  the query to be executed<a name="line.159"></a>
<FONT color="green">160</FONT>         * @param  con  the connection the query is to be executed against<a name="line.160"></a>
<FONT color="green">161</FONT>         * <a name="line.161"></a>
<FONT color="green">162</FONT>         * @throws SQLException if there is a problem executing the query.<a name="line.162"></a>
<FONT color="green">163</FONT>         */<a name="line.163"></a>
<FONT color="green">164</FONT>        public void executeQuery(Connection con, String query) throws SQLException {<a name="line.164"></a>
<FONT color="green">165</FONT>    <a name="line.165"></a>
<FONT color="green">166</FONT>            Statement statement = null;<a name="line.166"></a>
<FONT color="green">167</FONT>            ResultSet resultSet = null;<a name="line.167"></a>
<FONT color="green">168</FONT>    <a name="line.168"></a>
<FONT color="green">169</FONT>            try {<a name="line.169"></a>
<FONT color="green">170</FONT>                statement = con.createStatement();<a name="line.170"></a>
<FONT color="green">171</FONT>                resultSet = statement.executeQuery(query);<a name="line.171"></a>
<FONT color="green">172</FONT>                ResultSetMetaData metaData = resultSet.getMetaData();<a name="line.172"></a>
<FONT color="green">173</FONT>    <a name="line.173"></a>
<FONT color="green">174</FONT>                int columnCount = metaData.getColumnCount();<a name="line.174"></a>
<FONT color="green">175</FONT>                if (columnCount != 2) {<a name="line.175"></a>
<FONT color="green">176</FONT>                    throw new SQLException(<a name="line.176"></a>
<FONT color="green">177</FONT>                        "Invalid sql generated.  PieDataSet requires 2 columns only"<a name="line.177"></a>
<FONT color="green">178</FONT>                    );<a name="line.178"></a>
<FONT color="green">179</FONT>                }<a name="line.179"></a>
<FONT color="green">180</FONT>    <a name="line.180"></a>
<FONT color="green">181</FONT>                int columnType = metaData.getColumnType(2);<a name="line.181"></a>
<FONT color="green">182</FONT>                double value = Double.NaN;<a name="line.182"></a>
<FONT color="green">183</FONT>                while (resultSet.next()) {<a name="line.183"></a>
<FONT color="green">184</FONT>                    Comparable key = resultSet.getString(1);<a name="line.184"></a>
<FONT color="green">185</FONT>                    switch (columnType) {<a name="line.185"></a>
<FONT color="green">186</FONT>                        case Types.NUMERIC:<a name="line.186"></a>
<FONT color="green">187</FONT>                        case Types.REAL:<a name="line.187"></a>
<FONT color="green">188</FONT>                        case Types.INTEGER:<a name="line.188"></a>
<FONT color="green">189</FONT>                        case Types.DOUBLE:<a name="line.189"></a>
<FONT color="green">190</FONT>                        case Types.FLOAT:<a name="line.190"></a>
<FONT color="green">191</FONT>                        case Types.DECIMAL:<a name="line.191"></a>
<FONT color="green">192</FONT>                        case Types.BIGINT:<a name="line.192"></a>
<FONT color="green">193</FONT>                            value = resultSet.getDouble(2);<a name="line.193"></a>
<FONT color="green">194</FONT>                            setValue(key, value);<a name="line.194"></a>
<FONT color="green">195</FONT>                            break;<a name="line.195"></a>
<FONT color="green">196</FONT>    <a name="line.196"></a>
<FONT color="green">197</FONT>                        case Types.DATE:<a name="line.197"></a>
<FONT color="green">198</FONT>                        case Types.TIME:<a name="line.198"></a>
<FONT color="green">199</FONT>                        case Types.TIMESTAMP:<a name="line.199"></a>
<FONT color="green">200</FONT>                            Timestamp date = resultSet.getTimestamp(2);<a name="line.200"></a>
<FONT color="green">201</FONT>                            value = date.getTime();<a name="line.201"></a>
<FONT color="green">202</FONT>                            setValue(key, value);<a name="line.202"></a>
<FONT color="green">203</FONT>                            break;<a name="line.203"></a>
<FONT color="green">204</FONT>    <a name="line.204"></a>
<FONT color="green">205</FONT>                        default:<a name="line.205"></a>
<FONT color="green">206</FONT>                            System.err.println(<a name="line.206"></a>
<FONT color="green">207</FONT>                                "JDBCPieDataset - unknown data type"<a name="line.207"></a>
<FONT color="green">208</FONT>                            );<a name="line.208"></a>
<FONT color="green">209</FONT>                            break;<a name="line.209"></a>
<FONT color="green">210</FONT>                    }<a name="line.210"></a>
<FONT color="green">211</FONT>                }<a name="line.211"></a>
<FONT color="green">212</FONT>    <a name="line.212"></a>
<FONT color="green">213</FONT>                fireDatasetChanged();<a name="line.213"></a>
<FONT color="green">214</FONT>    <a name="line.214"></a>
<FONT color="green">215</FONT>            }<a name="line.215"></a>
<FONT color="green">216</FONT>            finally {<a name="line.216"></a>
<FONT color="green">217</FONT>                if (resultSet != null) {<a name="line.217"></a>
<FONT color="green">218</FONT>                    try {<a name="line.218"></a>
<FONT color="green">219</FONT>                        resultSet.close();<a name="line.219"></a>
<FONT color="green">220</FONT>                    }<a name="line.220"></a>
<FONT color="green">221</FONT>                    catch (Exception e) {<a name="line.221"></a>
<FONT color="green">222</FONT>                        System.err.println("JDBCPieDataset: swallowing exception.");<a name="line.222"></a>
<FONT color="green">223</FONT>                    }<a name="line.223"></a>
<FONT color="green">224</FONT>                }<a name="line.224"></a>
<FONT color="green">225</FONT>                if (statement != null) {<a name="line.225"></a>
<FONT color="green">226</FONT>                    try {<a name="line.226"></a>
<FONT color="green">227</FONT>                        statement.close();<a name="line.227"></a>
<FONT color="green">228</FONT>                    }<a name="line.228"></a>
<FONT color="green">229</FONT>                    catch (Exception e) {<a name="line.229"></a>
<FONT color="green">230</FONT>                        System.err.println("JDBCPieDataset: swallowing exception.");<a name="line.230"></a>
<FONT color="green">231</FONT>                    }<a name="line.231"></a>
<FONT color="green">232</FONT>                }<a name="line.232"></a>
<FONT color="green">233</FONT>            }<a name="line.233"></a>
<FONT color="green">234</FONT>        }<a name="line.234"></a>
<FONT color="green">235</FONT>    <a name="line.235"></a>
<FONT color="green">236</FONT>    <a name="line.236"></a>
<FONT color="green">237</FONT>        /**<a name="line.237"></a>
<FONT color="green">238</FONT>         * Close the database connection<a name="line.238"></a>
<FONT color="green">239</FONT>         */<a name="line.239"></a>
<FONT color="green">240</FONT>        public void close() {<a name="line.240"></a>
<FONT color="green">241</FONT>            try {<a name="line.241"></a>
<FONT color="green">242</FONT>                this.connection.close();<a name="line.242"></a>
<FONT color="green">243</FONT>            }<a name="line.243"></a>
<FONT color="green">244</FONT>            catch (Exception e) {<a name="line.244"></a>
<FONT color="green">245</FONT>                System.err.println("JdbcXYDataset: swallowing exception.");<a name="line.245"></a>
<FONT color="green">246</FONT>            }<a name="line.246"></a>
<FONT color="green">247</FONT>        }<a name="line.247"></a>
<FONT color="green">248</FONT>    }<a name="line.248"></a>




























































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