refactor sql parser.

src/main/java/com/alibaba/druid/sql/ast/SQLCommentHint.java

@@ -42,4 +42,8 @@ public class SQLCommentHint extends SQLObjectImpl implements SQLHint {
         visitor.visit(this);
         visitor.endVisit(this);
     }
+
+    public SQLCommentHint clone() {
+        return new SQLCommentHint(text);
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/SQLKeep.java

@@ -50,6 +50,19 @@ public class SQLKeep extends SQLObjectImpl {
         this.orderBy = orderBy;
     }
 
+
+    public SQLKeep clone() {
+        SQLKeep x = new SQLKeep();
+
+        x.denseRank = denseRank;
+
+        if (orderBy != null) {
+            x.setOrderBy(orderBy.clone());
+        }
+
+        return x;
+    }
+
     public static enum DenseRank {
                                   FIRST, //
                                   LAST

src/main/java/com/alibaba/druid/sql/ast/SQLLimit.java

@@ -70,4 +70,8 @@ public class SQLLimit extends SQLObjectImpl {
         visitor.endVisit(this);
     }
 
+    public SQLLimit clone() {
+        throw new UnsupportedOperationException();
+    }
+
 }

src/main/java/com/alibaba/druid/sql/ast/SQLObject.java

@@ -52,4 +52,6 @@ public interface SQLObject {
     boolean hasAfterComment();
 
     void output(StringBuffer buf);
+
+    SQLObject clone();
 }

src/main/java/com/alibaba/druid/sql/ast/SQLObjectImpl.java

@@ -20,6 +20,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import com.alibaba.druid.sql.dialect.oracle.ast.OracleSQLObject;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public abstract class SQLObjectImpl implements SQLObject {
@@ -206,4 +207,8 @@ public abstract class SQLObjectImpl implements SQLObject {
         
         return !comments.isEmpty();
     }
+
+    public SQLObject clone() {
+        throw new UnsupportedOperationException();
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/SQLOrderBy.java

@@ -96,4 +96,8 @@ public class SQLOrderBy extends SQLObjectImpl {
     protected SQLSelectOrderByItem createItem() {
         return new SQLSelectOrderByItem();
     }
+
+    public SQLOrderBy clone() {
+        throw new UnsupportedOperationException();
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/SQLOver.java

@@ -208,8 +208,45 @@ public class SQLOver extends SQLObjectImpl {
         return result;
     }
 
-    public SQLExpr clone() {
-        throw new UnsupportedOperationException();
+    public void cloneTo(SQLOver x) {
+        for (SQLExpr item : partitionBy) {
+            SQLExpr item1 = item.clone();
+            item1.setParent(x);
+            x.partitionBy.add(item);
+        }
+
+        if (orderBy != null) {
+            x.setOrderBy(orderBy.clone());
+        }
+
+        if (of != null) {
+            x.setOf(of.clone());
+        }
+
+        if (windowing != null) {
+            x.setWindowing(windowing.clone());
+        }
+        x.windowingType = windowingType;
+        x.windowingPreceding = windowingPreceding;
+        x.windowingFollowing = windowingFollowing;
+
+        if (windowingBetweenBegin != null) {
+            x.setWindowingBetweenBegin(windowingBetweenBegin.clone());
+        }
+        x.windowingBetweenBeginPreceding = windowingBetweenBeginPreceding;
+        x.windowingBetweenBeginFollowing = windowingBetweenBeginFollowing;
+
+        if (windowingBetweenEnd != null) {
+            x.setWindowingBetweenEnd(windowingBetweenEnd.clone());
+        }
+        x.windowingBetweenEndPreceding = windowingBetweenEndPreceding;
+        x.windowingBetweenEndFollowing = windowingBetweenEndFollowing;
+    }
+
+    public SQLOver clone() {
+        SQLOver x = new SQLOver();
+        cloneTo(x);
+        return x;
     }
 
     public static enum WindowingType {

src/main/java/com/alibaba/druid/sql/ast/expr/SQLAggregateExpr.java

@@ -176,4 +176,29 @@ public class SQLAggregateExpr extends SQLExprImpl implements Serializable {
         return true;
     }
 
+    public SQLAggregateExpr clone() {
+        SQLAggregateExpr x = new SQLAggregateExpr(methodName);
+
+        x.option = option;
+
+        for (SQLExpr arg : arguments) {
+            x.addArgument(arg.clone());
+        }
+
+        if (keep != null) {
+            x.setKeep(keep.clone());
+        }
+
+        if (over != null) {
+            x.setOver(over.clone());
+        }
+
+        if (withinGroup != null) {
+            x.setWithinGroup(withinGroup.clone());
+        }
+
+        x.ignoreNulls = ignoreNulls;
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLMethodInvokeExpr.java

@@ -144,4 +144,24 @@ public class SQLMethodInvokeExpr extends SQLExprImpl implements Serializable {
         result = 31 * result + (from != null ? from.hashCode() : 0);
         return result;
     }
+
+    public SQLMethodInvokeExpr clone() {
+        SQLMethodInvokeExpr x = new SQLMethodInvokeExpr();
+
+        x.methodName = methodName;
+
+        if (owner != null) {
+            x.setOwner(owner.clone());
+        }
+
+        for (SQLExpr param : parameters) {
+            x.addParameter(param.clone());
+        }
+
+        if (from != null) {
+            x.setFrom(from.clone());
+        }
+
+        return x;
+    }
 }

src/main/java/com/alibaba/druid/sql/ast/expr/SQLPropertyExpr.java

@@ -26,6 +26,10 @@ public class SQLPropertyExpr extends SQLExprImpl implements SQLName {
     private SQLExpr owner;
     private String  name;
 
+    public SQLPropertyExpr(String owner, String name){
+        this(new SQLIdentifierExpr(owner), name);
+    }
+
     public SQLPropertyExpr(SQLExpr owner, String name){
         setOwner(owner);
         this.name = name;

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

@@ -107,4 +107,43 @@ public class SQLExprTableSource extends SQLTableSourceImpl {
         result = 31 * result + (partitions != null ? partitions.hashCode() : 0);
         return result;
     }
+
+    public String computeAlias() {
+        String alias = this.getAlias();
+
+        if (alias == null) {
+            if (expr instanceof SQLName) {
+                alias =((SQLName) expr).getSimpleName();
+            }
+        }
+
+        if (alias.length() > 2) {
+            char c0 = alias.charAt(0);
+            char x0 = alias.charAt(alias.length() - 1);
+            if ((c0 == '"' && x0 == '"') || (c0 == '`' && x0 == '`')) {
+                alias = alias.substring(1, alias.length() - 1);
+            }
+        }
+
+        return alias;
+    }
+
+    public SQLExprTableSource clone() {
+        SQLExprTableSource x = new SQLExprTableSource();
+        cloneTo(x);
+        return x;
+    }
+
+    public void cloneTo(SQLExprTableSource x) {
+        if (expr != null) {
+            x.expr = expr.clone();
+        }
+
+        if (partitions != null) {
+            for (SQLName p : partitions) {
+                SQLName p1 = p.clone();
+                x.addPartition(p1);
+            }
+        }
+    }
 }

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

@@ -40,6 +40,13 @@ public class SQLJoinTableSource extends SQLTableSourceImpl {
 
     }
 
+    public SQLJoinTableSource(SQLTableSource left, JoinType joinType, SQLTableSource right, SQLExpr condition){
+        this.setLeft(left);
+        this.setJoinType(joinType);
+        this.setRight(right);
+        this.setCondition(condition);
+    }
+
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
             acceptChild(visitor, this.left);

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

@@ -19,11 +19,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import com.alibaba.druid.sql.SQLUtils;
-import com.alibaba.druid.sql.ast.SQLHint;
-import com.alibaba.druid.sql.ast.SQLObject;
-import com.alibaba.druid.sql.ast.SQLObjectImpl;
-import com.alibaba.druid.sql.ast.SQLOrderBy;
-import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.*;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
 public class SQLSelect extends SQLObjectImpl {
@@ -32,7 +28,16 @@ public class SQLSelect extends SQLObjectImpl {
     protected SQLSelectQuery        query;
     protected SQLOrderBy            orderBy;
 
-    protected List<SQLHint>           hints;
+    protected List<SQLHint>         hints;
+
+    protected SQLObject             restriction;
+
+    protected boolean               forBrowse;
+    protected List<String>          forXmlOptions = new ArrayList<String>(4);
+    protected SQLExpr               xmlPath;
+
+    protected SQLExpr                rowCount;
+    protected SQLExpr                offset;
 
     public SQLSelect(){
 
@@ -86,8 +91,11 @@ public class SQLSelect extends SQLObjectImpl {
     protected void accept0(SQLASTVisitor visitor) {
         if (visitor.visit(this)) {
             acceptChild(visitor, this.query);
+            acceptChild(visitor, this.restriction);
             acceptChild(visitor, this.orderBy);
             acceptChild(visitor, this.hints);
+            acceptChild(visitor, this.offset);
+            acceptChild(visitor, this.rowCount);
         }
 
         visitor.endVisit(this);
@@ -135,13 +143,85 @@ public class SQLSelect extends SQLObjectImpl {
     }
 
     public SQLSelect clone() {
-        SQLSelect clone = new SQLSelect();
+        SQLSelect x = new SQLSelect();
 
-        clone.withSubQuery = this.withSubQuery;
-        clone.query = this.query;
-        clone.orderBy = this.orderBy;
-        clone.hints = this.hints;
+        x.withSubQuery = this.withSubQuery;
+        x.query = this.query;
+        if (orderBy != null) {
+            x.setOrderBy(this.orderBy);
+        }
+        if (restriction != null) {
+            x.setRestriction(restriction.clone());
+        }
 
-        return clone;
+        if (this.hints != null) {
+            for (SQLHint hint : this.hints) {
+                x.hints.add(hint);
+            }
+        }
+
+        return x;
     }
+
+    public SQLObject getRestriction() {
+        return this.restriction;
+    }
+
+    public void setRestriction(SQLObject restriction) {
+        if (restriction != null) {
+            restriction.setParent(this);
+        }
+        this.restriction = restriction;
+    }
+
+    public boolean isForBrowse() {
+        return forBrowse;
+    }
+
+    public void setForBrowse(boolean forBrowse) {
+        this.forBrowse = forBrowse;
+    }
+
+    public List<String> getForXmlOptions() {
+        return forXmlOptions;
+    }
+
+    public void setForXmlOptions(List<String> forXmlOptions) {
+        this.forXmlOptions = forXmlOptions;
+    }
+
+    public SQLExpr getRowCount() {
+        return rowCount;
+    }
+
+    public void setRowCount(SQLExpr rowCount) {
+        if (rowCount != null) {
+            rowCount.setParent(this);
+        }
+
+        this.rowCount = rowCount;
+    }
+
+    public SQLExpr getOffset() {
+        return offset;
+    }
+
+    public void setOffset(SQLExpr offset) {
+        if (offset != null) {
+            offset.setParent(this);
+        }
+        this.offset = offset;
+    }
+
+    public SQLExpr getXmlPath() {
+        return xmlPath;
+    }
+
+    public void setXmlPath(SQLExpr xmlPath) {
+        if (xmlPath != null) {
+            xmlPath.setParent(this);
+        }
+        this.xmlPath = xmlPath;
+    }
+
 }

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

@@ -81,4 +81,8 @@ public class SQLSelectGroupByClause extends SQLObjectImpl {
             this.items.add(sqlExpr);
         }
     }
+
+    public SQLSelectGroupByClause clone() {
+        throw new UnsupportedOperationException();
+    }
 }

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

@@ -144,4 +144,13 @@ public class SQLSelectItem extends SQLObjectImpl {
         this.connectByRoot = connectByRoot;
     }
 
+    public SQLSelectItem clone() {
+        SQLSelectItem x = new SQLSelectItem();
+        x.alias = alias;
+        if (expr != null) {
+            x.expr = expr.clone();
+        }
+        x.connectByRoot = connectByRoot;
+        return x;
+    }
 }

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

@@ -130,6 +130,14 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         item.setParent(this);
     }
 
+    public void addSelectItem(SQLExpr expr) {
+        this.addSelectItem(new SQLSelectItem(expr));
+    }
+
+    public void addSelectItem(SQLExpr expr, String alias) {
+        this.addSelectItem(new SQLSelectItem(expr, alias));
+    }
+
     public SQLTableSource getFrom() {
         return this.from;
     }
@@ -308,4 +316,64 @@ public class SQLSelectQueryBlock extends SQLObjectImpl implements SQLSelectQuery
         return true;
     }
 
+    public SQLSelectQueryBlock clone() {
+        SQLSelectQueryBlock x = new SQLSelectQueryBlock();
+        clone(x);
+        return x;
+    }
+
+    public void clone(SQLSelectQueryBlock x) {
+
+        x.distionOption = distionOption;
+
+        for (SQLSelectItem item : this.selectList) {
+            x.addSelectItem(item.clone());
+        }
+
+        if (from != null) {
+            x.setFrom(from.clone());
+        }
+
+        if (into != null) {
+            x.setInto(into.clone());
+        }
+
+        if (where != null) {
+            x.setWhere(where.clone());
+        }
+
+        if (startWith != null) {
+            x.setStartWith(startWith.clone());
+        }
+
+        if (connectBy != null) {
+            x.setConnectBy(connectBy.clone());
+        }
+
+        x.prior = prior;
+        x.noCycle = noCycle;
+
+        if (orderBySiblings != null) {
+            x.setOrderBySiblings(orderBySiblings.clone());
+        }
+
+        if (groupBy != null) {
+            x.setGroupBy(groupBy.clone());
+        }
+
+        if (orderBy != null) {
+            x.setOrderBy(orderBy.clone());
+        }
+
+        x.parenthesized = parenthesized;
+        x.forUpdate = forUpdate;
+        x.noWait = noWait;
+        if (waitTime != null) {
+            x.setWaitTime(waitTime.clone());
+        }
+
+        if (limit != null) {
+            x.setLimit(limit.clone());
+        }
+    }
 }

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

@@ -38,6 +38,10 @@ public class SQLSubqueryTableSource extends SQLTableSourceImpl {
         this.setSelect(select);
     }
 
+    public SQLSubqueryTableSource(SQLSelectQuery query){
+        this(new SQLSelect(query));
+    }
+
     public SQLSelect getSelect() {
         return this.select;
     }
@@ -62,4 +66,12 @@ public class SQLSubqueryTableSource extends SQLTableSourceImpl {
         this.select.output(buf);
         buf.append(")");
     }
+
+    public SQLSubqueryTableSource clone() {
+        SQLSubqueryTableSource x = new SQLSubqueryTableSource();
+        if (select != null) {
+            x.select = select.clone();
+        }
+        return x;
+    }
 }

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

@@ -27,4 +27,6 @@ public interface SQLTableSource extends SQLObject {
     void setAlias(String alias);
     
     List<SQLHint> getHints();
+
+    SQLTableSource clone();
 }

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

@@ -62,4 +62,9 @@ public abstract class SQLTableSourceImpl extends SQLObjectImpl implements SQLTab
     public void setHints(List<SQLHint> hints) {
         this.hints = hints;
     }
+
+    public SQLTableSource clone() {
+        throw new UnsupportedOperationException();
+    }
+
 }