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POHow to run methods inside a standard try catch
 

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  1. POHow to run methods inside a standard try catch
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    <p>It's been a while since I have done any Java programming. And I find my self a bit stuck. </p> <p>My problem is that I have a pooled db connection in tomcat. That is working nicely. But there is a lot of boiler plate required. </p> <pre><code> public void init() { Connection conn = null; ResultSet rst = null; Statement stmt = null; try { //SETUP Context initContext = new InitialContext(); Context envContext = (Context) initContext.lookup("java:/comp/env/jdbc"); OracleDataSource ds = (OracleDataSource) envContext.lookup("tclsms"); if (envContext == null) throw new Exception("Error: No Context"); if (ds == null) throw new Exception("Error: No DataSource"); if (ds != null) conn = ds.getConnection(); if (conn == null) throw new Exception("Error: No Connection") message = "Got Connection " + conn.toString() + ", "; //BODY stmt = conn.createStatement(); rst = stmt.executeQuery("SELECT 'Success obtaining connection' FROM DUAL"); if (rst.next()) message = rst.getString(1); //TEAR DOWN rst.close(); rst = null; stmt.close(); stmt = null; conn.close(); // Return to connection pool conn = null; // Make sure we don't close it twice } catch (Exception e) { e.printStackTrace(); //TODO proper error handling } finally { // Always make sure result sets and statements are closed, // and the connection is returned to the pool if (rst != null) { try { rst.close(); } catch (SQLException e) {;} rst = null; } if (stmt != null) { try { stmt.close(); } catch (SQLException e) {;} stmt = null; } if (conn != null) { try { conn.close(); } catch (SQLException e) {;} conn = null; } } //END FINALLY } //END INIT </code></pre> <p>So I want to do the equivalent of passing a method into init that will run in the body of the function. I know I can't do this in Java. But I'm sure there must be a nice way to do this. Or at least a best practice for this sort of thing.</p> <p>Any help much appreciated.</p>
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    1. USDan Walmsley
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    1. COyou mean that you would like to have a method for setup, other for body, etc..??
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    2. COYeah sort of, more that I would like to have a standard wrapper for setup and tear down. So I do not have to copy and paste the same boilerplate every where.
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      1. USDan Walmsley
    3. COYou can cut down your boilerplate some by making a `Closer` object with several `close` methods each taking a different parameter: `Closeable`, `Connection`, `Statement`, `ResultSet`, etc. And otherwise, a common way to do this is to create a `TransactionExecutor` class that takes a `Runnable` style object and has an `execute` method which creates the transaction, executes the method from the Runnable style object passing in the `Connection` and/or `Statement` in as a parameter and handles cleanup when done via `try`/`finally` or some such.
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