ChunkFactoryGenerator.java

/*
 * Digital Audio Access Protocol (DAAP) Library
 * Copyright (C) 2004-2010 Roger Kapsi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.ardverk.daap.tools;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.util.Locale;

import org.ardverk.daap.chunks.Chunk;

public class ChunkFactoryGenerator {

    public static final String CLASS = "ChunkFactory";
    public static final String FILE = ChunkUtil.CHUNK_DIR + "/" + CLASS
            + ".java";

    public static final String CLASS_COMMENT = "/**\n"
            + " * This class is machine-made by {"
            + ChunkFactoryGenerator.class.getName()
            + "}!\n"
            + " * It is needed because Reflection cannot list the classes of a package so that we\n"
            + " * must pre-create a such list manually. This file must be rebuild whenever a class\n"
            + " * is removed or a class is added to the {@see de.kapsi.net.daap.chunks.impl} package.\n"
            + " */";

    public static void main(String[] args) throws Exception {
        StringBuffer buffer = new StringBuffer();
        buffer.append(CLASS_COMMENT);
        buffer.append("\n");

        buffer.append("package ").append(ChunkUtil.CHUNK_PACKAGE).append(";\n");
        buffer.append("\n");

        buffer.append("import java.util.HashMap;\n");
        buffer.append("import de.kapsi.net.daap.DaapUtil;\n");
        buffer.append("\n");

        buffer.append("public final class ").append(CLASS).append(" {\n\n");
        buffer.append("    private final HashMap map = new HashMap();\n\n");
        buffer.append("    public ").append(CLASS).append("() {\n");

        Chunk[] chunks = ChunkUtil.getChunks();

        for (int i = 0; i < chunks.length; i++) {
            Chunk chunk = chunks[i];
            String contentCode = "0x"
                    + Integer.toHexString(chunk.getContentCode()).toUpperCase(
                            Locale.US);
            String contentCodeString = chunk.getContentCodeString();
            // String name = chunk.getName();
            // int type = chunk.getType();

            buffer.append("        ");
            buffer.append("map.put(new Integer(").append(contentCode).append(
                    "), ").append(chunk.getClass().getName()).append(
                    ".class); //").append(contentCodeString);
            buffer.append("\n");
        }

        buffer.append("    }\n\n");

        buffer
                .append("    public Class getChunkClass(Integer contentCode) {\n");
        buffer.append("        return (Class)map.get(contentCode);\n");
        buffer.append("    }\n\n");

        buffer.append("    public Chunk newChunk(int contentCode) {\n");
        buffer
                .append("        Class clazz = getChunkClass(new Integer(contentCode));\n");
        buffer.append("        try {\n");
        buffer.append("            return (Chunk)clazz.newInstance();\n");
        buffer.append("        } catch (Exception err) {\n");
        buffer
                .append("            throw new RuntimeException(DaapUtil.toContentCodeString(contentCode), err);\n");
        buffer.append("        }\n");
        buffer.append("    }\n");

        buffer.append("}\n");

        System.out.println(buffer);

        BufferedWriter out = new BufferedWriter(new FileWriter(new File(FILE)));
        out.write(buffer.toString());
        out.close();
    }
}