SqlMapClient 创建过程之SqlMapConfigParser源码走读

public class SqlMapConfigParser {
	//初始化 NodeletParser
  protected final NodeletParser parser = new NodeletParser();
  //初始化XmlParserState
  private XmlParserState state = new XmlParserState();

  private boolean usingStreams = false;

  public SqlMapConfigParser() {
    parser.setValidation(true);
    parser.setEntityResolver(new SqlMapClasspathEntityResolver());
	//解析sqlMapConfig
    addSqlMapConfigNodelets();
	//解析全局属性
    addGlobalPropNodelets();
	//解析环境参数
    addSettingsNodelets();
	//解析别名配置
    addTypeAliasNodelets();
	//解析类型处理器
    addTypeHandlerNodelets();
	//解析事务
    addTransactionManagerNodelets();
	//解析sqlMap
    addSqlMapNodelets();
	//解析结果对象工厂配置
    addResultObjectFactoryNodelets();

  }

  public SqlMapClient parse(Reader reader, Properties props) {
    if (props != null) state.setGlobalProps(props);
    return parse(reader);
  }

  public SqlMapClient parse(Reader reader) {
    try {
      usingStreams = false;

      parser.parse(reader);
      return state.getConfig().getClient();
    } catch (Exception e) {
      throw new RuntimeException("Error occurred.  Cause: " + e, e);
    }
  }

  public SqlMapClient parse(InputStream inputStream, Properties props) {
    if (props != null) state.setGlobalProps(props);
    return parse(inputStream);
  }

  public SqlMapClient parse(InputStream inputStream) {
    try {
      usingStreams = true;

      parser.parse(inputStream);
      return state.getConfig().getClient();
    } catch (Exception e) {
      throw new RuntimeException("Error occurred.  Cause: " + e, e);
    }
  }

  private void addSqlMapConfigNodelets() {
    parser.addNodelet("/sqlMapConfig/end()", new Nodelet() {
      public void process(Node node) throws Exception {
        state.getConfig().finalizeSqlMapConfig();
      }
    });
  }
//解析sqlmap的属性配置
  private void addGlobalPropNodelets() {
    parser.addNodelet("/sqlMapConfig/properties", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String resource = attributes.getProperty("resource");
        String url = attributes.getProperty("url");
        state.setGlobalProperties(resource, url);
      }
    });
  }
 //解析sqlMapConfig setting节点数据
  private void addSettingsNodelets() {
    parser.addNodelet("/sqlMapConfig/settings", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
		//获取SqlMapConfiguration对象
        SqlMapConfiguration config = state.getConfig();
		//获取classInfoCacheEnabled属性值
        String classInfoCacheEnabledAttr = attributes.getProperty("classInfoCacheEnabled");
		//如果没有配置该属性，或将该属性设置为true则将sqlMapConfiguration的值设置为true
        boolean classInfoCacheEnabled = (classInfoCacheEnabledAttr == null || "true".equals(classInfoCacheEnabledAttr));
        config.setClassInfoCacheEnabled(classInfoCacheEnabled);
		// 获取lazyLoadingEnabled属性值，是否启用懒加载
        String lazyLoadingEnabledAttr = attributes.getProperty("lazyLoadingEnabled");
		//默认是开启lazyLoadingEnabled
        boolean lazyLoadingEnabled = (lazyLoadingEnabledAttr == null || "true".equals(lazyLoadingEnabledAttr));
        config.setLazyLoadingEnabled(lazyLoadingEnabled);
		//获取statementCachingEnabled属性值，是否开启statement的缓存
        String statementCachingEnabledAttr = attributes.getProperty("statementCachingEnabled");
		//默认是开启的
        boolean statementCachingEnabled = (statementCachingEnabledAttr == null || "true".equals(statementCachingEnabledAttr));
        config.setStatementCachingEnabled(statementCachingEnabled);
		//获取cachedModelsEnabled的属性值，默认是true,该值是表示是否开启SqlMapClient上的缓存机制
        String cacheModelsEnabledAttr = attributes.getProperty("cacheModelsEnabled");
        boolean cacheModelsEnabled = (cacheModelsEnabledAttr == null || "true".equals(cacheModelsEnabledAttr));
        config.setCacheModelsEnabled(cacheModelsEnabled);
		// 获取enhancementEnabled的属性值，默认是true，该值表示是否针对POJO开启字节码增强机制，减少reflet的性能开销
        String enhancementEnabledAttr = attributes.getProperty("enhancementEnabled");
        boolean enhancementEnabled = (enhancementEnabledAttr == null || "true".equals(enhancementEnabledAttr));
        config.setEnhancementEnabled(enhancementEnabled);
		//获取useColumnLabel的属性值，默认是true
        String useColumnLabelAttr = attributes.getProperty("useColumnLabel");
        boolean useColumnLabel = (useColumnLabelAttr == null || "true".equals(useColumnLabelAttr));
        config.setUseColumnLabel(useColumnLabel);
		//获取forceMultipleResultSetSupport的属性值，默认值是false
        String forceMultipleResultSetSupportAttr = attributes.getProperty("forceMultipleResultSetSupport");
        boolean forceMultipleResultSetSupport = "true".equals(forceMultipleResultSetSupportAttr);
        config.setForceMultipleResultSetSupport(forceMultipleResultSetSupport);
		//获取defaultSatementTimeout的属性值，默认值是null；JDBC连接的超时时间，默认是无时间限制
        String defaultTimeoutAttr = attributes.getProperty("defaultStatementTimeout");
        Integer defaultTimeout = defaultTimeoutAttr == null ? null : Integer.valueOf(defaultTimeoutAttr);
        config.setDefaultStatementTimeout(defaultTimeout);
		//获取useStatementNamespaces的属性值，默认值是false：是否使用命名空间
        String useStatementNamespacesAttr = attributes.getProperty("useStatementNamespaces");
        boolean useStatementNamespaces = "true".equals(useStatementNamespacesAttr);
        state.setUseStatementNamespaces(useStatementNamespaces);
      }
    });
  }

  private void addTypeAliasNodelets() {
    parser.addNodelet("/sqlMapConfig/typeAlias", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties prop = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String alias = prop.getProperty("alias");
        String type = prop.getProperty("type");
        state.getConfig().getTypeHandlerFactory().putTypeAlias(alias, type);
      }
    });
  }
// 解析SqlMapConfig中typeHandler节点配置
  private void addTypeHandlerNodelets() {
    parser.addNodelet("/sqlMapConfig/typeHandler", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties prop = NodeletUtils.parseAttributes(node, state.getGlobalProps());
		//获取jdbcType,javaType,callback的属性值
        String jdbcType = prop.getProperty("jdbcType");
        String javaType = prop.getProperty("javaType");
        String callback = prop.getProperty("callback");
		//根据javaType,callback作为别名去TypeHandlerFactory获取映射值，如果不是别名则返回原始值
        javaType = state.getConfig().getTypeHandlerFactory().resolveAlias(javaType);
        callback = state.getConfig().getTypeHandlerFactory().resolveAlias(callback);
		//在SqlMapConfiguration实例中设置TypeHandler
        state.getConfig().newTypeHandler(Resources.classForName(javaType), jdbcType, Resources.instantiate(callback));
      }
    });
  }
// 解析SqlMapConfig中transactionManager节点下的属性配置
  private void addTransactionManagerNodelets() {
    parser.addNodelet("/sqlMapConfig/transactionManager/property", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String name = attributes.getProperty("name");
        String value = NodeletUtils.parsePropertyTokens(attributes.getProperty("value"), state.getGlobalProps());
        state.getTxProps().setProperty(name, value);
      }
    });
    parser.addNodelet("/sqlMapConfig/transactionManager/end()", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String type = attributes.getProperty("type");
        boolean commitRequired = "true".equals(attributes.getProperty("commitRequired"));

        state.getConfig().getErrorContext().setActivity("configuring the transaction manager");
        type = state.getConfig().getTypeHandlerFactory().resolveAlias(type);
        TransactionManager txManager;
        try {
          state.getConfig().getErrorContext().setMoreInfo("Check the transaction manager type or class.");
          TransactionConfig config = (TransactionConfig) Resources.instantiate(type);
          config.setDataSource(state.getDataSource());
          state.getConfig().getErrorContext().setMoreInfo("Check the transactio nmanager properties or configuration.");
          config.setProperties(state.getTxProps());
          config.setForceCommit(commitRequired);
          config.setDataSource(state.getDataSource());
          state.getConfig().getErrorContext().setMoreInfo(null);
          txManager = new TransactionManager(config);
        } catch (Exception e) {
          if (e instanceof SqlMapException) {
            throw (SqlMapException) e;
          } else {
            throw new SqlMapException("Error initializing TransactionManager.  Could not instantiate TransactionConfig.  Cause: " + e, e);
          }
        }
        state.getConfig().setTransactionManager(txManager);
      }
    });
	//解析dataSource属性
    parser.addNodelet("/sqlMapConfig/transactionManager/dataSource/property", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String name = attributes.getProperty("name");
        String value = NodeletUtils.parsePropertyTokens(attributes.getProperty("value"), state.getGlobalProps());
        state.getDsProps().setProperty(name, value);
      }
    });
    parser.addNodelet("/sqlMapConfig/transactionManager/dataSource/end()", new Nodelet() {
      public void process(Node node) throws Exception {
        state.getConfig().getErrorContext().setActivity("configuring the data source");

        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());

        String type = attributes.getProperty("type");
        Properties props = state.getDsProps();

        type = state.getConfig().getTypeHandlerFactory().resolveAlias(type);
        try {
          state.getConfig().getErrorContext().setMoreInfo("Check the data source type or class.");
          DataSourceFactory dsFactory = (DataSourceFactory) Resources.instantiate(type);
          state.getConfig().getErrorContext().setMoreInfo("Check the data source properties or configuration.");
          dsFactory.initialize(props);
          state.setDataSource(dsFactory.getDataSource());
          state.getConfig().getErrorContext().setMoreInfo(null);
        } catch (Exception e) {
          if (e instanceof SqlMapException) {
            throw (SqlMapException) e;
          } else {
            throw new SqlMapException("Error initializing DataSource.  Could not instantiate DataSourceFactory.  Cause: " + e, e);
          }
        }
      }
    });
  }


  protected void addSqlMapNodelets() {
  //解析sqlMap
    parser.addNodelet("/sqlMapConfig/sqlMap", new Nodelet() {
      public void process(Node node) throws Exception {
        state.getConfig().getErrorContext().setActivity("loading the SQL Map resource");

        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());

        String resource = attributes.getProperty("resource");
        String url = attributes.getProperty("url");

        if (usingStreams) {
          InputStream inputStream = null;
          if (resource != null) {
            state.getConfig().getErrorContext().setResource(resource);
            inputStream = Resources.getResourceAsStream(resource);
          } else if (url != null) {
            state.getConfig().getErrorContext().setResource(url);
            inputStream = Resources.getUrlAsStream(url);
          } else {
            throw new SqlMapException("The <sqlMap> element requires either a resource or a url attribute.");
          }
		//使用SQLMapParser解析sqlMap
          new SqlMapParser(state).parse(inputStream);
        } else {
          Reader reader = null;
          if (resource != null) {
            state.getConfig().getErrorContext().setResource(resource);
            reader = Resources.getResourceAsReader(resource);
          } else if (url != null) {
            state.getConfig().getErrorContext().setResource(url);
            reader = Resources.getUrlAsReader(url);
          } else {
            throw new SqlMapException("The <sqlMap> element requires either a resource or a url attribute.");
          }

          new SqlMapParser(state).parse(reader);
        }
      }
    });
  }
//解析resultObjectFactory
  private void addResultObjectFactoryNodelets() {
    parser.addNodelet("/sqlMapConfig/resultObjectFactory", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String type = attributes.getProperty("type");

        state.getConfig().getErrorContext().setActivity("configuring the Result Object Factory");
        ResultObjectFactory rof;
        try {
          rof = (ResultObjectFactory) Resources.instantiate(type);
          state.getConfig().setResultObjectFactory(rof);
        } catch (Exception e) {
          throw new SqlMapException("Error instantiating resultObjectFactory: " + type, e);
        }

      }
    });
    parser.addNodelet("/sqlMapConfig/resultObjectFactory/property", new Nodelet() {
      public void process(Node node) throws Exception {
        Properties attributes = NodeletUtils.parseAttributes(node, state.getGlobalProps());
        String name = attributes.getProperty("name");
        String value = NodeletUtils.parsePropertyTokens(attributes.getProperty("value"), state.getGlobalProps());
        state.getConfig().getDelegate().getResultObjectFactory().setProperty(name, value);
      }
    });
  }

}