add mapping support

src/main/java/com/alibaba/druid/mapping/DruidMappingException.java

@@ -0,0 +1,23 @@
+package com.alibaba.druid.mapping;
+
+public class DruidMappingException extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+
+    public DruidMappingException(){
+        super();
+    }
+
+    public DruidMappingException(String message, Throwable cause){
+        super(message, cause);
+    }
+
+    public DruidMappingException(String message){
+        super(message);
+    }
+
+    public DruidMappingException(Throwable cause){
+        super(cause);
+    }
+
+}

src/main/java/com/alibaba/druid/mapping/Entity.java

@@ -1,15 +1,24 @@
 package com.alibaba.druid.mapping;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.LinkedHashMap;
+import java.util.Map;
 
 public class Entity {
 
-    private String         name;
-    private String         description;
-    private String         tableName;
+    private String                name;
+    private String                description;
+    private String                tableName;
 
-    private List<Property> properties = new ArrayList<Property>();
+    private Map<String, Property> properties = new LinkedHashMap<String, Property>();
+
+    public Entity(){
+    }
+
+    public Entity(String name, String description, String tableName){
+        this.name = name;
+        this.description = description;
+        this.tableName = tableName;
+    }
 
     public String getName() {
         return name;
@@ -35,11 +44,30 @@ public class Entity {
         this.tableName = tableName;
     }
 
-    public List<Property> getProperties() {
+    public void addProperty(Property property) {
+        this.properties.put(property.getName(), property);
+    }
+
+    public Property getProperty(String name) {
+        Property prop = this.properties.get(name);
+
+        if (prop == null) {
+            for (Map.Entry<String, Property> entry : properties.entrySet()) {
+                if (entry.getKey().equalsIgnoreCase(name)) {
+                    prop = entry.getValue();
+                    break;
+                }
+            }
+        }
+
+        return prop;
+    }
+
+    public Map<String, Property> getProperties() {
         return properties;
     }
 
-    public void setProperties(List<Property> properties) {
+    public void setProperties(Map<String, Property> properties) {
         this.properties = properties;
     }
 

src/main/java/com/alibaba/druid/mapping/EntityMapingMySqlVisitor.java

@@ -1,18 +1,150 @@
 package com.alibaba.druid.mapping;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
+import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
+import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
+import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
+import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlASTVisitorAdapter;
 
 public class EntityMapingMySqlVisitor extends MySqlASTVisitorAdapter {
 
-    private final Entity entity;
+    private final LinkedHashMap<String, Entity> entities;
 
-    public EntityMapingMySqlVisitor(Entity entity){
-        super();
-        this.entity = entity;
+    public EntityMapingMySqlVisitor(LinkedHashMap<String, Entity> entities){
+        this.entities = entities;
     }
 
-    public Entity getEntity() {
+    public Map<String, Entity> getEntities() {
+        return entities;
+    }
+
+    public Entity getFirstEntity() {
+        for (Map.Entry<String, Entity> entry : entities.entrySet()) {
+            return entry.getValue();
+        }
+
+        return null;
+    }
+
+    public Entity getEntity(String name) {
+        Entity entity = this.entities.get(name);
+
+        if (entity == null) {
+            for (Map.Entry<String, Entity> entry : entities.entrySet()) {
+                if (entry.getKey().equalsIgnoreCase(name)) {
+                    entity = entry.getValue();
+                    break;
+                }
+            }
+        }
+
         return entity;
     }
 
+    public boolean visit(SQLSelectItem x) {
+        x.getExpr().setParent(x);
+        return true;
+    }
+
+    public boolean visit(MySqlSelectQueryBlock x) {
+        if (x.getSelectList().size() == 0) {
+            fillSelectList(x);
+        }
+
+        if (x.getSelectList().size() == 1) {
+            if (x.getSelectList().get(0).getExpr() instanceof SQLAllColumnExpr) {
+                x.getSelectList().clear();
+                fillSelectList(x);
+            }
+        }
+        
+        if (x.getFrom() == null) {
+            Entity firstEntity = this.getFirstEntity();
+            SQLExprTableSource from = new SQLExprTableSource(new SQLIdentifierExpr(firstEntity.getName()));
+            x.setFrom(from);
+        }
+
+        for (SQLSelectItem item : x.getSelectList()) {
+            item.setParent(x);
+        }
+
+        return super.visit(x);
+    }
+
+    public boolean visit(SQLSelectQueryBlock x) {
+        if (x instanceof MySqlSelectQueryBlock) {
+            return visit((MySqlSelectQueryBlock) x);
+        }
+
+        if (x.getSelectList().size() == 0) {
+            fillSelectList(x);
+        }
+
+        for (SQLSelectItem item : x.getSelectList()) {
+            item.setParent(x);
+        }
+
+        return super.visit(x);
+    }
+
+    protected void fillSelectList(SQLSelectQueryBlock x) {
+        Entity entity = getFirstEntity();
+
+        for (Property item : entity.getProperties().values()) {
+            x.getSelectList().add(new SQLSelectItem(new SQLIdentifierExpr(item.getName()), '"' + item.getName() + '"'));
+        }
+    }
+
+    public boolean visit(SQLIdentifierExpr x) {
+        String propertyName = x.getName();
+
+        Property property = null;
+        for (Entity entity : this.entities.values()) {
+            property = entity.getProperty(propertyName);
+            if (property != null) {
+                break;
+            }
+        }
+
+        if (property == null) {
+            throw new DruidMappingException("property not found : " + propertyName);
+        }
+
+        String dbColumName = property.getDbColumnName();
+        x.setName(dbColumName);
+
+        if (x.getParent() instanceof SQLSelectItem) {
+            SQLSelectItem selectItem = (SQLSelectItem) x.getParent();
+            if (selectItem.getAlias() == null) {
+                selectItem.setAlias('"' + property.getName() + '"');
+            }
+        }
+
+        return false;
+    }
+
+    public boolean visit(SQLExprTableSource x) {
+        SQLExpr expr = x.getExpr();
+
+        if (expr instanceof SQLIdentifierExpr) {
+            SQLIdentifierExpr tableExpr = (SQLIdentifierExpr) expr;
+            String entityName = tableExpr.getName();
+
+            Entity entity = this.getEntity(entityName);
+            
+            if (entity == null) {
+                throw new DruidMappingException("entity not foudn : " + entityName);
+            }
+
+            tableExpr.setName(entity.getTableName());
+        }
+
+        return false;
+    }
 }

src/main/java/com/alibaba/druid/mapping/MappingEngine.java

@@ -0,0 +1,63 @@
+package com.alibaba.druid.mapping;
+
+import java.util.LinkedHashMap;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.expr.SQLNumberExpr;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock.Limit;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlSelectParser;
+
+public class MappingEngine {
+
+    private LinkedHashMap<String, Entity> entities = new LinkedHashMap<String, Entity>();
+    private Integer                       maxLimit;
+
+    public Integer getMaxLimit() {
+        return maxLimit;
+    }
+
+    public void setMaxLimit(Integer maxLimit) {
+        this.maxLimit = maxLimit;
+    }
+
+    public LinkedHashMap<String, Entity> getEntities() {
+        return entities;
+    }
+
+    public void addEntity(Entity entity) {
+        this.entities.put(entity.getName(), entity);
+    }
+
+    public EntityMapingMySqlVisitor createMappingVisitor() {
+        return new EntityMapingMySqlVisitor(entities);
+    }
+
+    public String explain(String sql) {
+        MySqlSelectQueryBlock query = explainToSQLObject(sql);
+
+        if (this.maxLimit != null) {
+            if (query.getLimit() == null) {
+                Limit limit = new Limit();
+                limit.setRowCount(new SQLNumberExpr(maxLimit));
+                query.setLimit(limit);
+            } else {
+                SQLNumberExpr rowCountExpr = (SQLNumberExpr) query.getLimit().getRowCount();
+                int rowCount = rowCountExpr.getNumber().intValue();
+                if (rowCount > maxLimit.intValue()) {
+                    rowCountExpr.setNumber(maxLimit);
+                }
+            }
+        }
+
+        query.accept(this.createMappingVisitor());
+
+        return SQLUtils.toMySqlString(query);
+    }
+
+    public MySqlSelectQueryBlock explainToSQLObject(String sql) {
+        MySqlSelectParser selectParser = new MySqlSelectParser(sql);
+        MySqlSelectQueryBlock query = (MySqlSelectQueryBlock) selectParser.query();
+        return query;
+    }
+}

src/main/java/com/alibaba/druid/mapping/Property.java

@@ -3,8 +3,18 @@ package com.alibaba.druid.mapping;
 public class Property {
 
     private String name;
+    private String desciption;
     private String dbColumnName;
 
+    public Property(){
+    }
+
+    public Property(String name, String desciption, String dbColumnName){
+        this.name = name;
+        this.desciption = desciption;
+        this.dbColumnName = dbColumnName;
+    }
+
     public String getName() {
         return name;
     }
@@ -21,4 +31,12 @@ public class Property {
         this.dbColumnName = dbColumnName;
     }
 
+    public String getDesciption() {
+        return desciption;
+    }
+
+    public void setDesciption(String desciption) {
+        this.desciption = desciption;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/SQLUtils.java

@@ -0,0 +1,34 @@
+package com.alibaba.druid.sql;
+
+import com.alibaba.druid.sql.ast.SQLObject;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlOutputVisitor;
+import com.alibaba.druid.sql.dialect.oracle.visitor.OracleOutputVisitor;
+import com.alibaba.druid.sql.dialect.postgresql.visitor.PGOutputVisitor;
+
+public class SQLUtils {
+
+    public static String toMySqlString(SQLObject sqlObject) {
+        StringBuilder out = new StringBuilder();
+        sqlObject.accept(new MySqlOutputVisitor(out));
+
+        String sql = out.toString();
+        return sql;
+    }
+    
+    public static String toOracleString(SQLObject sqlObject) {
+        StringBuilder out = new StringBuilder();
+        sqlObject.accept(new OracleOutputVisitor(out));
+        
+        String sql = out.toString();
+        return sql;
+    }
+    
+    public static String toPGString(SQLObject sqlObject) {
+        StringBuilder out = new StringBuilder();
+        sqlObject.accept(new PGOutputVisitor(out));
+        
+        String sql = out.toString();
+        return sql;
+    }
+ 
+}

src/main/java/com/alibaba/druid/sql/ast/statement/SQLExprTableSource.java

@@ -27,8 +27,10 @@ public class SQLExprTableSource extends SQLTableSourceImpl {
     public SQLExprTableSource(){
 
     }
-    
-    
+
+    public SQLExprTableSource(SQLExpr expr){
+        this.expr = expr;
+    }
 
     public SQLExpr getExpr() {
         return this.expr;

src/main/java/com/alibaba/druid/sql/dialect/mysql/visitor/MySqlMappingVisitor.java

@@ -1,16 +0,0 @@
-package com.alibaba.druid.sql.dialect.mysql.visitor;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import com.alibaba.druid.sql.ast.SQLExpr;
-
-public class MySqlMappingVisitor extends MySqlASTVisitorAdapter {
-
-    private final Map<String, SQLExpr> mapping = new HashMap<String, SQLExpr>();
-    
-    public void addMapping(String column, String targetExpr) {
-        
-    }
-    
-}

src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -85,14 +85,22 @@ import com.alibaba.druid.sql.ast.statement.SQLUpdateStatement;
 
 public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
 
-    protected Appendable appender;
-    private String       indent      = "\t";
-    private int          indentCount = 0;
+    protected final Appendable appender;
+    private String             indent      = "\t";
+    private int                indentCount = 0;
 
     public SQLASTOutputVisitor(Appendable appender){
         this.appender = appender;
     }
 
+    public int getIndentCount() {
+        return indentCount;
+    }
+
+    public Appendable getAppender() {
+        return appender;
+    }
+
     public void decrementIndent() {
         this.indentCount -= 1;
     }
@@ -213,8 +221,8 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
         if (x.getLeft() instanceof SQLBinaryOpExpr) {
             SQLBinaryOpExpr left = (SQLBinaryOpExpr) x.getLeft();
             boolean leftRational = left.getOperator() == SQLBinaryOperator.BooleanAnd
-                    || left.getOperator() == SQLBinaryOperator.BooleanOr;
-            
+                                   || left.getOperator() == SQLBinaryOperator.BooleanOr;
+
             if (left.getOperator().priority > x.getOperator().priority) {
                 if (leftRational) {
                     incrementIndent();
@@ -222,7 +230,7 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
                 print('(');
                 left.accept(this);
                 print(')');
-                
+
                 if (leftRational) {
                     decrementIndent();
                 }
@@ -257,11 +265,11 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
                 if (rightRational) {
                     incrementIndent();
                 }
-                
+
                 print('(');
                 right.accept(this);
                 print(')');
-                
+
                 if (rightRational) {
                     decrementIndent();
                 }
@@ -985,5 +993,5 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter {
 
         return false;
     }
-    
+
 }

src/main/java/com/alibaba/druid/sql/visitor/SQLASTVisitor.java

@@ -135,7 +135,7 @@ public interface SQLASTVisitor {
 
     boolean visit(SQLExistsExpr x);
 
-    boolean visit(SQLIdentifierExpr astNode);
+    boolean visit(SQLIdentifierExpr x);
 
     boolean visit(SQLInListExpr x);
 

src/main/java/com/alibaba/druid/sql/visitor/SQLASTVisitorAdapter.java

@@ -172,7 +172,7 @@ public class SQLASTVisitorAdapter implements SQLASTVisitor {
         return true;
     }
 
-    public boolean visit(SQLIdentifierExpr astNode) {
+    public boolean visit(SQLIdentifierExpr x) {
         return true;
     }
 

src/main/java/com/alibaba/druid/util/JdbcUtils.java

@@ -22,21 +22,28 @@ import java.io.PrintStream;
 import java.io.PrintWriter;
 import java.io.Reader;
 import java.io.StringWriter;
+import java.math.BigDecimal;
 import java.net.URL;
 import java.sql.Connection;
 import java.sql.Date;
 import java.sql.Driver;
+import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.sql.Types;
 import java.text.SimpleDateFormat;
+import java.util.ArrayList;
 import java.util.Enumeration;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import com.alibaba.druid.logging.Log;
 import com.alibaba.druid.logging.LogFactory;
+import com.alibaba.druid.mapping.DruidMappingException;
 
 /**
  * @author wenshao<szujobs@hotmail.com>
@@ -520,6 +527,69 @@ public final class JdbcUtils {
         }
     }
     
+    public static List<Map<String, Object>> executeQuery(Connection conn, String sql, List<Object> parameters) {
+        List<Map<String, Object>> rows = new ArrayList<Map<String, Object>>();
+
+        PreparedStatement stmt = null;
+        ResultSet rs = null;
+        try {
+            stmt = conn.prepareStatement(sql);
+
+            for (int i = 0, size = parameters.size(); i < size; ++i) {
+                Object val = parameters.get(i);
+                int paramIndex = i + 1;
+                
+                if (val == null) {
+                    stmt.setNull(paramIndex, Types.VARCHAR);
+                } else if (val instanceof BigDecimal) {
+                    stmt.setBigDecimal(paramIndex, (BigDecimal) val);
+                } else if (val instanceof String) {
+                    stmt.setString(paramIndex, (String) val);
+                } else if (val instanceof Date) {
+                    long time = ((Date) val).getTime();
+                    stmt.setTimestamp(paramIndex, new java.sql.Timestamp(time));
+                } else if (val instanceof Byte) {
+                    stmt.setByte(paramIndex, (Byte) val);
+                } else if (val instanceof Short) {
+                    stmt.setShort(paramIndex, (Short) val);
+                } else if (val instanceof Integer) {
+                    stmt.setInt(paramIndex, (Integer) val);
+                } else if (val instanceof Long) {
+                    stmt.setLong(paramIndex, (Long) val);
+                } else if (val instanceof Float) {
+                    stmt.setFloat(paramIndex, (Float) val);
+                } else if (val instanceof Double) {
+                    stmt.setDouble(paramIndex, (Double) val);
+                } else {
+                    throw new DruidMappingException("not support parameters : " + val);
+                }
+            }
+
+            rs = stmt.executeQuery();
+            
+            ResultSetMetaData rsMeta = rs.getMetaData();
+            
+            while (rs.next()) {
+                Map<String, Object> row = new LinkedHashMap<String, Object>();
+                
+                for (int i = 0, size = rsMeta.getColumnCount(); i < size; ++i) {
+                    String columName = rsMeta.getColumnName(i + 1);
+                    Object value = rs.getObject(i + 1);
+                    row.put(columName, value);
+                }
+                
+                rows.add(row);
+            }
+        } catch (SQLException e) {
+            throw new DruidMappingException("execute error", e);
+        } finally {
+            JdbcUtils.close(rs);
+            JdbcUtils.close(stmt);
+        }
+
+        return rows;
+    }
+    
     public static String toString(StackTraceElement[] stackTrace) {
         StringBuilder buf = new StringBuilder();
         for (StackTraceElement item : stackTrace) {

src/test/java/com/alibaba/druid/bvt/mapping/MappingVisitorTest.java

@@ -0,0 +1,45 @@
+package com.alibaba.druid.bvt.mapping;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.mapping.Entity;
+import com.alibaba.druid.mapping.MappingEngine;
+import com.alibaba.druid.mapping.Property;
+
+public class MappingVisitorTest extends TestCase {
+
+    MappingEngine engine = new MappingEngine();
+
+    protected void setUp() throws Exception {
+        Entity entity = new Entity();
+        entity.setName("设备");
+        entity.setDescription("Device");
+        entity.setTableName("device");
+
+        entity.addProperty(new Property("编号", "", "serviceTag"));
+        entity.addProperty(new Property("IP地址", "", "ip"));
+
+        engine.addEntity(entity);
+    }
+
+    public void test_0() throws Exception {
+
+        Assert.assertEquals("SELECT serviceTag AS \"编号\", ip AS \"IP地址\"\nFROM device", engine.explain("select *"));
+        Assert.assertEquals("SELECT serviceTag AS \"编号\", ip AS \"IP地址\"\nFROM device\nWHERE ip = '127.0.0.1'",
+                            engine.explain("select 编号, IP地址 WHERE IP地址 = '127.0.0.1'"));
+
+    }
+    
+    public void test_1() throws Exception {
+        engine.setMaxLimit(10);
+        
+        Assert.assertEquals("SELECT serviceTag AS \"编号\", ip AS \"IP地址\"\nFROM device\nLIMIT 10", engine.explain("select *"));
+        Assert.assertEquals("SELECT serviceTag AS \"编号\", ip AS \"IP地址\"\nFROM device\nWHERE ip = '127.0.0.1'\nLIMIT 10",
+                            engine.explain("select 编号, IP地址 WHERE IP地址 = '127.0.0.1'"));
+        
+        engine.setMaxLimit(null);
+
+    }
+}