jdbcproxygenerator.java

c3p0数据库连接池实现源码

	    iw.println("out = new NewProxyDatabaseMetaData( (DatabaseMetaData) out, parentPooledConnection );");
	    iw.downIndent();
	    iw.println("return out;");
	    iw.downIndent();
	    iw.println("}");
	    iw.println();
	    iw.println("synchronized void maybeDirtyTransaction()");
	    iw.println("{ txn_known_resolved = false; }");

	    super.generateExtraDeclarations( intfcl, genclass, iw );
	}

	void generateFindMethodAndArgs( Method method, IndentedWriter iw ) throws IOException
	{
	    iw.println("Class[] argTypes = ");
	    iw.println("{");
	    iw.upIndent();
	    
	    Class[] argTypes = method.getParameterTypes();
	    for (int i = 0, len = argTypes.length; i < len; ++i)
		{
		    if (i != 0) iw.println(",");
		    iw.print( CodegenUtils.simpleClassName( argTypes[i] ) + ".class" );
		}
	    iw.println();
	    iw.downIndent();
	    iw.println("};");
	    iw.println("Method method = Connection.class.getMethod( \042" + method.getName() + "\042 , argTypes );");
	    iw.println();
	    iw.println("Object[] args = ");
	    iw.println("{");
	    iw.upIndent();
	    
	    for (int i = 0, len = argTypes.length; i < len; ++i)
		{
		    if (i != 0) iw.println(",");
		    String argName = CodegenUtils.generatedArgumentName( i );
		    Class argType = argTypes[i];
		    if (argType.isPrimitive())
			{
			    if (argType == boolean.class)
				iw.print( "Boolean.valueOf( " + argName + " )" );
			    else if (argType == byte.class)
				iw.print( "new Byte( " + argName + " )" );
			    else if (argType == char.class)
				iw.print( "new Character( " + argName + " )" );
			    else if (argType == short.class)
				iw.print( "new Short( " + argName + " )" );
			    else if (argType == int.class)
				iw.print( "new Integer( " + argName + " )" );
			    else if (argType == long.class)
				iw.print( "new Long( " + argName + " )" );
			    else if (argType == float.class)
				iw.print( "new Float( " + argName + " )" );
			    else if (argType == double.class)
				iw.print( "new Double( " + argName + " )" );
			}
		    else
			iw.print( argName );
		}
	    
	    iw.downIndent();
	    iw.println("};");
	}

	protected void generateExtraImports( IndentedWriter iw ) throws IOException
	{
	    super.generateExtraImports( iw );
	    iw.println("import java.lang.reflect.InvocationTargetException;");
	}
    }

    protected void generatePreDelegateCode( Class intfcl, String genclass, Method method, IndentedWriter iw ) throws IOException 
    {
	generateTryOpener( iw );
    }
    
    protected void generatePostDelegateCode( Class intfcl, String genclass, Method method, IndentedWriter iw ) throws IOException 
    {
	generateTryCloserAndCatch( intfcl, genclass, method, iw );
    }

    void generateTryOpener( IndentedWriter iw ) throws IOException
    {
	iw.println("try");
	iw.println("{");
	iw.upIndent();
    }

    void generateTryCloserAndCatch( Class intfcl, String genclass, Method method, IndentedWriter iw ) throws IOException
    {
	iw.downIndent();
	iw.println("}");
	iw.println("catch (NullPointerException exc)");
	iw.println("{");
	iw.upIndent();
	iw.println("if ( this.isDetached() )");
	iw.println("{");
	iw.upIndent();
	//iw.println( "System.err.print(\042probably 'cuz we're closed -- \042);" );
	//iw.println( "exc.printStackTrace();" );
	if ( "close".equals( method.getName() ) )
	    {
		iw.println("if (Debug.DEBUG && logger.isLoggable( MLevel.FINE ))");
		iw.println("{");
		iw.upIndent();
		iw.println("logger.log( MLevel.FINE, this + \042: close() called more than once.\042 );");

		// premature-detach-debug-debug only!
		if (PREMATURE_DETACH_DEBUG)
		    {
			iw.println("prematureDetachRecorder.record();");
			iw.println("logger.warning( prematureDetachRecorder.getDump(\042Apparent multiple close of " + 
				   getInnerTypeName() + ".\042) );");
		    }
		// end-premature-detach-debug-only!

		iw.downIndent();
		iw.println("}");
	    }
	else
	    {
		// premature-detach-debug-debug only!
		if (PREMATURE_DETACH_DEBUG)
		    {
			iw.println("prematureDetachRecorder.record();");
			iw.println("logger.warning( prematureDetachRecorder.getDump(\042Use of already detached " + 
				   getInnerTypeName() + ".\042) );");
		    }
		// end-premature-detach-debug-only!

		iw.println( "throw SqlUtils.toSQLException(\042You can't operate on a closed " + getInnerTypeName() + "!!!\042, exc);");
	    }
	iw.downIndent();
	iw.println("}");
	iw.println( "else throw exc;" );
	iw.downIndent();
	iw.println("}");
	iw.println("catch (Exception exc)");
	iw.println("{");
	iw.upIndent();
	iw.println("if (! this.isDetached())");
	iw.println("{");
	iw.upIndent();
	//iw.println( "exc.printStackTrace();" );
	iw.println( "throw parentPooledConnection.handleThrowable( exc );" );
	iw.downIndent();
	iw.println("}");
	iw.println("else throw SqlUtils.toSQLException( exc );");
	iw.downIndent();
	iw.println("}");
    }

    protected void generateExtraDeclarations( Class intfcl, String genclass, IndentedWriter iw ) throws IOException
    {
	// premature-detach-debug-debug only!
	if (PREMATURE_DETACH_DEBUG)
	    {
		iw.println("com.mchange.v2.debug.ThreadNameStackTraceRecorder prematureDetachRecorder");
		iw.upIndent();
		iw.println("= new com.mchange.v2.debug.ThreadNameStackTraceRecorder(\042Premature Detach Recorder\042);");
		iw.downIndent();
	    }
	// end-premature-detach-debug-only!

	iw.println("private final static MLogger logger = MLog.getLogger( \042" + genclass + "\042 );");
	iw.println();

	iw.println("volatile NewPooledConnection parentPooledConnection;");
	iw.println();

	iw.println("ConnectionEventListener cel = new ConnectionEventListener()");
	iw.println("{");
	iw.upIndent();

	iw.println("public void connectionErrorOccurred(ConnectionEvent evt)");
	iw.println("{ /* DON'T detach()... IGNORE -- this could be an ordinary error. Leave it to the PooledConnection to test, but leave proxies intact */ }");
	//BAD puppy -- iw.println("{ detach(); }");

	iw.println();
	iw.println("public void connectionClosed(ConnectionEvent evt)");
	iw.println("{ detach(); }");

	iw.downIndent();
	iw.println("};");
	iw.println();
	
	iw.println("void attach( NewPooledConnection parentPooledConnection )");
	iw.println("{");
	iw.upIndent();
	iw.println("this.parentPooledConnection = parentPooledConnection;");
	iw.println("parentPooledConnection.addConnectionEventListener( cel );");
	iw.downIndent();
	iw.println("}");
	iw.println();
	iw.println("private void detach()");
	iw.println("{");
	iw.upIndent();

	// factored out so we could define debug versions...
	writeDetachBody(iw);

	iw.downIndent();
	iw.println("}");
	iw.println();
	iw.print( CodegenUtils.fqcnLastElement( genclass ) );
	iw.println("( " + CodegenUtils.simpleClassName( intfcl ) + " inner, NewPooledConnection parentPooledConnection )");
	iw.println("{");
	iw.upIndent();
	iw.println("this( inner );");
	iw.println("attach( parentPooledConnection );");
	generateExtraConstructorCode( intfcl, genclass,  iw );
	iw.downIndent();
	iw.println("}");
	iw.println();
	iw.println("boolean isDetached()");
	iw.println("{ return (this.parentPooledConnection == null); }");
    }

    protected void writeDetachBody(IndentedWriter iw) throws IOException
    {
	// premature-detach-debug only
	if (PREMATURE_DETACH_DEBUG)
	    {
		iw.println("prematureDetachRecorder.record();");
		iw.println("if (this.isDetached())");
		iw.upIndent();
		iw.println("logger.warning( prematureDetachRecorder.getDump(\042Double Detach.\042) );");
		iw.downIndent();
	    }
	// end premature-detach-debug only

	iw.println("parentPooledConnection.removeConnectionEventListener( cel );");
	iw.println("parentPooledConnection = null;");
    }

    protected void generateExtraImports( IndentedWriter iw ) throws IOException
    {
	iw.println("import java.sql.*;");
	iw.println("import javax.sql.*;");
	iw.println("import com.mchange.v2.log.*;");
	iw.println("import java.lang.reflect.Method;");
	iw.println("import com.mchange.v2.sql.SqlUtils;");
    }

    void generateExtraConstructorCode( Class intfcl, String genclass, IndentedWriter iw ) throws IOException
    {}

    public static void main( String[] argv )
    {
	try
	    {
		if (argv.length != 1)
		    {
			System.err.println("java " + JdbcProxyGenerator.class.getName() + " <source-root-directory>");
			return;
		    }

		File srcroot = new File( argv[0] );
		if (! srcroot.exists() || !srcroot.canWrite() )
		    {
			System.err.println(JdbcProxyGenerator.class.getName() + " -- sourceroot: " + argv[0] + " must exist and be writable");
			return;
		    }

		DelegatorGenerator mdgen = new NewProxyMetaDataGenerator();
		DelegatorGenerator rsgen = new NewProxyResultSetGenerator();
		DelegatorGenerator stgen = new NewProxyAnyStatementGenerator();
		DelegatorGenerator cngen = new NewProxyConnectionGenerator();
		
		genclass( cngen, Connection.class, "com.mchange.v2.c3p0.impl.NewProxyConnection", srcroot );
		genclass( stgen, Statement.class, "com.mchange.v2.c3p0.impl.NewProxyStatement", srcroot );
		genclass( stgen, PreparedStatement.class, "com.mchange.v2.c3p0.impl.NewProxyPreparedStatement", srcroot );
		genclass( stgen, CallableStatement.class, "com.mchange.v2.c3p0.impl.NewProxyCallableStatement", srcroot );
		genclass( rsgen, ResultSet.class, "com.mchange.v2.c3p0.impl.NewProxyResultSet", srcroot );
		genclass( mdgen, DatabaseMetaData.class, "com.mchange.v2.c3p0.impl.NewProxyDatabaseMetaData", srcroot );
	    }
	catch ( Exception e )
	    { e.printStackTrace(); }
    }

    static void genclass( DelegatorGenerator dg, Class intfcl, String fqcn, File srcroot ) throws IOException
    {
	File genDir = new File( srcroot, dirForFqcn( fqcn ) );
	if (! genDir.exists() )
	    {
		System.err.println( JdbcProxyGenerator.class.getName() + " -- creating directory: " + genDir.getAbsolutePath() );
		genDir.mkdirs();
	    }
	String fileName = CodegenUtils.fqcnLastElement( fqcn ) + ".java";
	Writer w = null;
	try
	    {
		w = new BufferedWriter( new FileWriter( new File( genDir, fileName ) ) );
		dg.writeDelegator( intfcl, fqcn, w );
		w.flush();
		System.err.println("Generated " + fileName);
	    }
	finally
	    {
		try { if (w != null) w.close(); }
		catch ( Exception e )
		    { e.printStackTrace(); }
	    }		
    }

    static String dirForFqcn( String fqcn )
    {
	int last_dot = fqcn.lastIndexOf('.');
	StringBuffer sb = new StringBuffer( fqcn.substring( 0, last_dot + 1) );
	for (int i = 0, len = sb.length(); i < len; ++i)
	    if (sb.charAt(i) == '.')
		sb.setCharAt(i, '/');
	return sb.toString();
    }
}