/*
* 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
* <p>
*
*
* @author 王志亮 [qieqie.wang@gmail.com]
*/
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
*/
private final String sql;
/**
* 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
* <p>
* 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;
/**
* <code>@{@link ShardBy}</code>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 int parameterCount;
// --------------------------------------------
public StatementMetaData(DAOMetaData daoMetaData, Method method) {
this.daoMetaData = daoMetaData;
this.method = method;
this.sql = method.getAnnotation(SQL.class).value();
this.genericReturnTypes = GenericUtils.getActualClass(method.getGenericReturnType());
Annotation[][] annotations = method.getParameterAnnotations();
this.parameterCount = annotations.length;
this.sqlParams = new SQLParam[annotations.length];
int shardByIndex = -1;
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;
} else if (annotation instanceof SQLParam) {
this.sqlParams[index] = (SQLParam) annotation;
}
}
}
this.shardByIndex = shardByIndex;
}
public DAOMetaData getDAOMetaData() {
return daoMetaData;
}
public Method getMethod() {
return method;
}
public String getSQL() {
return sql;
}
public int getParameterCount() {
return parameterCount;
}
public SQLParam getSQLParamAt(int argIndex) {
return sqlParams[argIndex];
}
public int getShardByIndex() {
return shardByIndex;
}
public Class<?>[] getGenericReturnTypes() {
return genericReturnTypes;
}
public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
return method.getAnnotation(annotationClass);
}
@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\\s+", Pattern.CASE_INSENSITIVE), //
Pattern.compile("^\\s*SHOW\\s+", Pattern.CASE_INSENSITIVE), //
Pattern.compile("^\\s*DESC\\s+", Pattern.CASE_INSENSITIVE), //
Pattern.compile("^\\s*DESCRIBE\\s+", Pattern.CASE_INSENSITIVE), //
};
private SQLType sqlType;
public SQLType getSQLType() {
if (sqlType == null) {
SQL sql = method.getAnnotation(SQL.class);
SQLType sqlType = sql.type();
if (sqlType == SQLType.AUTO_DETECT) {
for (int i = 0; i < SELECT_PATTERNS.length; i++) {
// 用正则表达式匹配 SELECT 语句
if (SELECT_PATTERNS[i].matcher(getSQL()).find()) {
sqlType = SQLType.READ;
break;
}
}
if (sqlType == SQLType.AUTO_DETECT) {
sqlType = SQLType.WRITE;
}
}
this.sqlType = sqlType;
}
return sqlType;
}
}