com.alibaba.dubbo.common.Version Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of dubbo2 Show documentation
The all in one project of dubbo2
The newest version!
/*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * 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 com.alibaba.dubbo.common;

import java.net.URL;
import java.security.CodeSource;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;

import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.ClassHelper;

/**
 * Version
 * 
 * @author william.liangf
 */
public final class Version {

    private Version() {}

    private static final Logger logger = LoggerFactory.getLogger(Version.class);

    private static final String VERSION = getVersion(Version.class, "2.0.0");

    private static final boolean INTERNAL = hasResource("com/alibaba/dubbo/registry/internal/RemoteRegistry.class");

    private static final boolean COMPATIBLE = hasResource("com/taobao/remoting/impl/ConnectionRequest.class");

    static {
        // 检查是否存在重复的jar包
    	Version.checkDuplicate(Version.class);
	}

    public static String getVersion(){
    	return VERSION;
    }
    
    public static boolean isInternalVersion() {
        return INTERNAL;
    }

    public static boolean isCompatibleVersion() {
        return COMPATIBLE;
    }
    
    private static boolean hasResource(String path) {
        try {
            return Version.class.getClassLoader().getResource(path) != null;
        } catch (Throwable t) {
            return false;
        }
    }
    
    public static String getVersion(Class cls, String defaultVersion) {
        try {
            // 首先查找MANIFEST.MF规范中的版本号
            String version = cls.getPackage().getImplementationVersion();
            if (version == null || version.length() == 0) {
                version = cls.getPackage().getSpecificationVersion();
            }
            if (version == null || version.length() == 0) {
                // 如果规范中没有版本号，基于jar包名获取版本号
                CodeSource codeSource = cls.getProtectionDomain().getCodeSource();
                if(codeSource == null) {
                    logger.info("No codeSource for class " + cls.getName() + " when getVersion, use default version " + defaultVersion);
                }
                else {
                    String file = codeSource.getLocation().getFile();
                    if (file != null && file.length() > 0 && file.endsWith(".jar")) {
                        file = file.substring(0, file.length() - 4);
                        int i = file.lastIndexOf('/');
                        if (i >= 0) {
                            file = file.substring(i + 1);
                        }
                        i = file.indexOf("-");
                        if (i >= 0) {
                            file = file.substring(i + 1);
                        }
                        while (file.length() > 0 && ! Character.isDigit(file.charAt(0))) {
                            i = file.indexOf("-");
                            if (i >= 0) {
                                file = file.substring(i + 1);
                            } else {
                                break;
                            }
                        }
                        version = file;
                    }
                }
            }
            // 返回版本号，如果为空返回缺省版本号
            return version == null || version.length() == 0 ? defaultVersion : version;
        } catch (Throwable e) { // 防御性容错
            // 忽略异常，返回缺省版本号
            logger.error("return default version, ignore exception " + e.getMessage(), e);
            return defaultVersion;
        }
    }

    public static void checkDuplicate(Class cls, boolean failOnError) {
        checkDuplicate(cls.getName().replace('.', '/') + ".class", failOnError);
    }

	public static void checkDuplicate(Class cls) {
		checkDuplicate(cls, false);
	}

	public static void checkDuplicate(String path, boolean failOnError) {
		try {
			// 在ClassPath搜文件
			Enumeration urls = ClassHelper.getCallerClassLoader(Version.class).getResources(path);
			Set files = new HashSet();
			while (urls.hasMoreElements()) {
				URL url = urls.nextElement();
				if (url != null) {
					String file = url.getFile();
					if (file != null && file.length() > 0) {
						files.add(file);
					}
				}
			}
			// 如果有多个，就表示重复
			if (files.size() > 1) {
                String error = "Duplicate class " + path + " in " + files.size() + " jar " + files;
                if (failOnError) {
                    throw new IllegalStateException(error);
                } else {
				    logger.error(error);
                }
			}
		} catch (Throwable e) { // 防御性容错
			logger.error(e.getMessage(), e);
		}
	}

}