/* * Copyright 2009-2012 the original author or authors. * * 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 i 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 net.paoding.rose.jade.statement; import java.lang.annotation.Annotation; import java.lang.reflect.Method; import java.util.regex.Pattern; import net.paoding.rose.jade.annotation.SQL; import net.paoding.rose.jade.annotation.SQLParam; import net.paoding.rose.jade.annotation.SQLType; import net.paoding.rose.jade.annotation.ShardBy; /** * {@link StatementMetaData} 封装、缓存了一个DAO方法的相关信息 *

* * * @author 王志亮 [qieqie.wang@gmail.com] */ @SuppressWarnings({ "rawtypes" }) public class StatementMetaData { /** * 所属的DAO类的classMetaData */ private final DAOMetaData daoMetaData; /** * 所在的DAO方法 */ private final Method method; /** * DAO方法上的原始SQL语句,如果没有执行SQL语句,则根据方法签名生成相应的串辅助debug */ private final String sql; /** * SQL类型(查询类型或者更新类型):默认由方法名和SQL语句判断,除非强制指定。 * @see SQLType */ private final SQLType sqlType; /** * DAO方法的“最低返回类型”。 *

* 大部分情况returnType和method.getReturnType是相同的,但对于一些声明为泛型的返回类型, * Jade会尽量提取出实际的类型作为returnType *

* 比如: * *

     * //@DAO、@SQL注解从略
     * public interface BaseDAO[E] {
     * 
     *     public E getById(Long id);
     * 
     * }
     * public interface UserDAO extends BaseDAO[User] {
     * 
     * }
     * 
* * 此时,UserDAO#getById方法的returnType是User,而非Object; */ private final Class returnType; /** * 方法返回参数的范型类型(不支持多级)-从method中获取并缓存 */ private final Class[] genericReturnTypes; /** * {@link SQLParam} 注解数组-从method中获取并缓存 *

* 此数组的长度为方法的参数个数,如果对应位置的方法参数没有注解 {@link SQLParam},该位置的元素值为null */ private final SQLParam[] sqlParams; /** * @{@link ShardBy}标注在哪个参数上?(从0开始,负数代表无)-从method中获取并缓存 */ private final int shardByIndex; private final ShardBy shardBy; private final int parameterCount; // -------------------------------------------- public StatementMetaData(DAOMetaData daoMetaData, Method method) { this.daoMetaData = daoMetaData; this.method = method; SQL sqlAnnotation = method.getAnnotation(SQL.class); if (sqlAnnotation == null) { sqlAnnotation = new SQL() { @Override public Class annotationType() { return SQL.class; } @Override public String value() { String toString = StatementMetaData.this.method.toString(); int paramStart = toString.indexOf("("); int methodNameStart = toString.lastIndexOf('.', paramStart) + 1; return toString.substring(methodNameStart) + "@" + StatementMetaData.this.method.getDeclaringClass().getName(); } @Override public SQLType type() { return SQLType.AUTO_DETECT; } }; } this.sql = sqlAnnotation.value(); this.sqlType = resolveSQLType(sqlAnnotation); this.returnType = GenericUtils.getReturnType(this); this.genericReturnTypes = GenericUtils.getActualClass(method.getGenericReturnType(), daoMetaData); Annotation[][] annotations = method.getParameterAnnotations(); this.parameterCount = annotations.length; this.sqlParams = new SQLParam[annotations.length]; int shardByIndex = -1; ShardBy shardBy = null; for (int index = 0; index < annotations.length; index++) { for (Annotation annotation : annotations[index]) { if (annotation instanceof ShardBy) { if (shardByIndex >= 0) { throw new IllegalArgumentException("duplicated @" + ShardBy.class.getName()); } shardByIndex = index; shardBy = (ShardBy) annotation; } else if (annotation instanceof SQLParam) { this.sqlParams[index] = (SQLParam) annotation; } } } this.shardByIndex = shardByIndex; this.shardBy = shardBy; } public DAOMetaData getDAOMetaData() { return daoMetaData; } public Method getMethod() { return method; } public Class getReturnType() { return returnType; } public String getSQL() { return sql; } public int getParameterCount() { return parameterCount; } public SQLParam getSQLParamAt(int argIndex) { return sqlParams[argIndex]; } public int getShardByIndex() { return shardByIndex; } public ShardBy getShardBy() { return shardBy; } public Class[] getGenericReturnTypes() { return genericReturnTypes; } public T getAnnotation(Class annotationClass) { return method.getAnnotation(annotationClass); } public SQLType getSQLType() { return sqlType; } private SQLType resolveSQLType(SQL sql) { SQLType sqlType = sql.type(); if (sqlType == SQLType.AUTO_DETECT) { for (Pattern selectPattern : SELECT_PATTERNS) { // 用正则表达式匹配 SELECT 语句 if (selectPattern.matcher(getSQL()).find() || selectPattern.matcher(getMethod().getName()).find()) { sqlType = SQLType.READ; break; } } if (sqlType == SQLType.AUTO_DETECT) { sqlType = SQLType.WRITE; } } return sqlType; } @Override public boolean equals(Object obj) { if (obj instanceof StatementMetaData) { StatementMetaData modifier = (StatementMetaData) obj; return daoMetaData.equals(modifier.daoMetaData) && method.equals(modifier.method); } return false; } @Override public int hashCode() { return daoMetaData.hashCode() ^ method.hashCode(); } @Override public String toString() { return daoMetaData.getDAOClass().getName() + '#' + method.getName(); } private static Pattern[] SELECT_PATTERNS = new Pattern[] { Pattern.compile("^\\s*SELECT.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*GET.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*FIND.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*READ.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*QUERY.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*SHOW.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*DESC.*", Pattern.CASE_INSENSITIVE), Pattern.compile("^\\s*DESCRIBE.*", Pattern.CASE_INSENSITIVE), }; }