factorybuilder.java

Java的面向对象数据库系统的源代码

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
//
// $Id$
package org.ozoneDB.tools.OPP.srcgen.builder;

import org.ozoneDB.tools.OPP.OPPHelper;
import org.ozoneDB.tools.OPP.message.MessageWriter;
import org.ozoneDB.tools.OPP.srcgen.ClassBuilder;
import org.ozoneDB.tools.OPP.srcgen.BuilderException;
import org.ozoneDB.tools.OPP.srcgen.streamfactory.OutputStreamFactory;

import java.io.*;
import java.lang.reflect.Modifier;

/**
 * Most of the code was lifted out of the FactoryGenerator written by
 * Leo Mekenkamp. The FactoryGenerator was in turn based on the ProxyGenerator
 *
 * The FactoryBuilder is in fact half of the FactoryGenerate, the
 * generating part. The rest of the FactoryGenerator had to do with
 * browsing a class for constructors etc. That part is moved to a
 * director, thus separating concerns.
 *
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @author <a href="http://www.medium.net/">Medium.net</a>
 * @author Per Nyfelt
 * @author <a href="mailto://ozone-db.orgATmekenkampD0Tcom">Leo Mekenkamp</a>
 * @author Joakim Ohlrogge
 */
public class FactoryBuilder implements ClassBuilder {
    private OutputStreamFactory outputFactory;
    private String postfix;
    private PrintWriter out = null;
    private String[] interfaces;
    private MessageWriter msgWriter;

    public FactoryBuilder(OutputStreamFactory outputFactory, String postfix) {
        this.outputFactory = outputFactory;
        this.postfix = postfix;
    }

    private void makeCreateInternal(String implementationClass, String type) {
        out.println("    private " + type + " createInternal(OzonePersonalMetaData personalMeta, OzoneSharedMetaData sharedMeta, Class[] ctorArgTypes, Object[] ctorArgs) throws Exception {");
        out.println("        String name = null;");
        out.println("        int access = OzoneInterface.Public;");
        out.println("        if (personalMeta != null) {");
        out.println("            name = personalMeta.getName();");
        out.println("        }");
        out.println("        if (sharedMeta != null) {");
        out.println("            access = sharedMeta.getAccess();");
        out.println("        }");
        out.println("        return (" + type + ") getDatabase().createObject(" + implementationClass + ".class, access, name, ctorArgTypes, ctorArgs);");
        out.println("    }\n");
    }

    private void makeGlobalHeader(String implementationClass) {
        out.println("// Factory class generated by ozone's OPP ($Revision$).");
        out.println("// DO NOT EDIT!\n");
        if (!OPPHelper.packageName(implementationClass).equals("")) {
            out.println("package " + OPPHelper.packageName(implementationClass) + ";\n");
        }
        out.println("import org.ozoneDB.AbstractFactory;");
        out.println("import org.ozoneDB.OzonePersonalMetaData;");
        out.println("import org.ozoneDB.OzoneSharedMetaData;");
        out.println("import org.ozoneDB.OzoneInterface;");
        out.println("import org.ozoneDB.OzoneInternalException;");
        out.println("import org.ozoneDB.OzoneProxy;");
        out.println("import org.ozoneDB.tools.OPP.OPP;\n");
    }

    private void makeLocalHeader(String simpleClassName) {
        out.println("/**");
        out.println(" * <p>This class is generated by OPP. DO NOT EDIT, for it will be overwritten");
        out.println(" * the next time OPP is run for <code>" + simpleClassName + "</code>.</p>");
        out.println(" * <p>Factory pattern class for creating ozone objects.</p>");
        out.println(" * A factory has a bit of a schizophrenic nature: on the client-side it 'links'");
        out.println(" * to an ExternalDatabase, while on the server-side it does so to the Database");
        out.println(" * that holds the instances that the factory creates. Note however that a");
        out.println(" * factory running inside an Ozone server can also be linked to an External");
        out.println(" * database outside that server (userclient -> server A -> server B). In that");
        out.println(" * case such a factory would be 'linked' to an ExternalDatabase.</p>");
        out.println(" * <p>The idea behind factories is threefold:<ul>\n");
        out.println(" * <li>provide an abstraction from Ozone specific object creation</li>");
        out.println(" * <li>facilitate creating objects with non-default constructors</li>");
        out.println(" * <li>provide (almost) the same interface on the server side and the client");
        out.println(" * side on object creation</li></ul>");
        out.println(" * The differences in client side and server side operation are:<ul>");
        out.println(" * <li>on the server side <code>getDefault()</code> returns a factory that is");
        out.println(" * creates its objects inside that same server database and on the client side");
        out.println(" * it returns a factory that creates its objects in the default database</li>");
        out.println(" * <li>In order to use <code>getDefault()<code> on the client side, you need to");
        out.println(" * call <code>setDefaultDatabaseUrl(String)</code> to specify the default");
        out.println(" * database.</li>");
        out.println(" * In a typical real-world scenario where you connect to only one ozone database");
        out.println(" * you would call <code>setDefaultDatabaseUrl(String)</code> on the client only");
        out.println(" * once, and for the rest of the programs lifespan call");
        out.println(" * <code>" + simpleClassName + ".getDefault().create()</code> methods both on the server and");
        out.println(" * client sides to create objects.</p>");
        out.println(" * <p>Note: if you do not have a clue what factories are and how they work, you");
        out.println(" * should probably brush up on your knowledge of");
        out.println(" * <a href=\"http://www.google.com/search?q=java+design+patterns+GoF\">design patterns</a></p>.");
        out.println(" * @author <a href=\"mailto://ozone-db.orgATmekenkampD0Tcom\">Leo Mekenkamp</a>");
        out.println(" * @since FIXME(since when?)");
        out.println(" */\n");
        out.println("public final class " + simpleClassName + " extends AbstractFactory {\n");
        out.println("    private static class Info implements org.ozoneDB.FactoryClassInfo {");
        out.println("        public final void defaultDatabaseUrlChanged() {");
        out.println("            defaultInstance = null;");
        out.println("        }");
        out.println("    }\n");
        out.println("    static {");
        out.println("        addFactoryClassInfo(new Info());");
        out.println("    }\n");
        out.println("    private static " + simpleClassName + " defaultInstance = null;\n");
        out.println("    /**");
        out.println("     * On the client side: returns a factory that is linked to a database");
        out.println("     * specified by the url passed to <code>setDefaultDatabaseUrl</code>. On the");
        out.println("     * server side: returns a factory that is linked to the server database.");
        out.println("     * Note that multiple calls to this method return the same value over and");
        out.println("     * over again, until <code>setDefaultDatabaseUrl</code> has been called.");
        out.println("     */");
        out.println("    public static synchronized " + simpleClassName + " getDefault() throws Exception {");
        out.println("        if (defaultInstance == null) {");
        out.println("            defaultInstance = new " + simpleClassName + "();");
        out.println("        }");
        out.println("        return defaultInstance;");
        out.println("    }\n");
        // constructors
        out.println("    /**");
        out.println("     * <p>Default constructor: creates a factory that is liked to the default");
        out.println("     * database.</p>");
        out.println("     */");
        out.println("    public " + simpleClassName + "() throws Exception {");
        out.println("    }\n");
        out.println("    /** <p>Creates a factory that creates its objects in the database specified by");
        out.println("     * <code>url</code>. Note that this constructor can only be used if the database in");
        out.println("     * question is not opened by this client. Use <code>" + simpleClassName + "()</code> or");
        out.println("     * <code>" + simpleClassName + "(Factory)</code> to create a factory for an already opened");
        out.println("     * database. This might seem strange, or even annoying at first, but it is very");