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An JDBC datasource implementation.
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* 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 is 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 com.alibaba.druid.sql.ast.statement;
import com.alibaba.druid.sql.SQLUtils;
import com.alibaba.druid.sql.ast.*;
import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
import com.alibaba.druid.sql.ast.expr.SQLPropertyExpr;
import com.alibaba.druid.sql.dialect.oracle.ast.OracleSQLObject;
import com.alibaba.druid.sql.visitor.SQLASTVisitor;
import com.alibaba.druid.util.FnvHash;
import com.alibaba.druid.util.JdbcConstants;
public class SQLSelectItem extends SQLObjectImpl implements SQLReplaceable {
protected SQLExpr expr;
protected String alias;
protected boolean connectByRoot = false;
protected transient long aliasHashCode64;
public SQLSelectItem(){
}
public SQLSelectItem(SQLExpr expr){
this(expr, null);
}
public SQLSelectItem(SQLExpr expr, String alias){
this.expr = expr;
this.alias = alias;
if (expr != null) {
expr.setParent(this);
}
}
public SQLSelectItem(SQLExpr expr, String alias, boolean connectByRoot){
this.connectByRoot = connectByRoot;
this.expr = expr;
this.alias = alias;
if (expr != null) {
expr.setParent(this);
}
}
public SQLExpr getExpr() {
return this.expr;
}
public void setExpr(SQLExpr expr) {
if (expr != null) {
expr.setParent(this);
}
this.expr = expr;
}
public String computeAlias() {
String alias = this.getAlias();
if (alias == null) {
if (expr instanceof SQLIdentifierExpr) {
alias = ((SQLIdentifierExpr) expr).getName();
} else if (expr instanceof SQLPropertyExpr) {
alias = ((SQLPropertyExpr) expr).getName();
}
}
return SQLUtils.normalize(alias);
}
public SQLDataType computeDataType() {
if (expr == null) {
return null;
}
return expr.computeDataType();
}
public String getAlias() {
return this.alias;
}
public void setAlias(String alias) {
this.alias = alias;
}
public void output(StringBuffer buf) {
if(this.connectByRoot) {
buf.append(" CONNECT_BY_ROOT ");
}
this.expr.output(buf);
if ((this.alias != null) && (this.alias.length() != 0)) {
buf.append(" AS ");
buf.append(this.alias);
}
}
protected void accept0(SQLASTVisitor visitor) {
if (visitor.visit(this)) {
acceptChild(visitor, this.expr);
}
visitor.endVisit(this);
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((alias == null) ? 0 : alias.hashCode());
result = prime * result + ((expr == null) ? 0 : expr.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
SQLSelectItem other = (SQLSelectItem) obj;
if (alias == null) {
if (other.alias != null) return false;
} else if (!alias.equals(other.alias)) return false;
if (expr == null) {
if (other.expr != null) return false;
} else if (!expr.equals(other.expr)) return false;
return true;
}
public boolean isConnectByRoot() {
return connectByRoot;
}
public void setConnectByRoot(boolean connectByRoot) {
this.connectByRoot = connectByRoot;
}
public SQLSelectItem clone() {
SQLSelectItem x = new SQLSelectItem();
x.alias = alias;
if (expr != null) {
x.setExpr(expr.clone());
}
x.connectByRoot = connectByRoot;
return x;
}
@Override
public boolean replace(SQLExpr expr, SQLExpr target) {
if (expr == expr) {
setExpr(target);
return true;
}
return false;
}
public boolean match(String alias) {
if (alias == null) {
return false;
}
long hash = FnvHash.hashCode64(alias);
return match(hash);
}
public long alias_hash() {
if (this.aliasHashCode64 == 0) {
this.aliasHashCode64 = FnvHash.hashCode64(alias);
}
return aliasHashCode64;
}
public boolean match(long alias_hash) {
long hash = alias_hash();
if (hash == alias_hash) {
return true;
}
if (expr instanceof SQLAllColumnExpr) {
SQLTableSource resolvedTableSource = ((SQLAllColumnExpr) expr).getResolvedTableSource();
if (resolvedTableSource != null
&& resolvedTableSource.findColumn(alias_hash) != null) {
return true;
}
return false;
}
if (expr instanceof SQLIdentifierExpr) {
return ((SQLIdentifierExpr) expr).nameHashCode64() == alias_hash;
}
if (expr instanceof SQLPropertyExpr) {
String ident = ((SQLPropertyExpr) expr).getName();
if ("*".equals(ident)) {
SQLTableSource resolvedTableSource = ((SQLPropertyExpr) expr).getResolvedTableSource();
if (resolvedTableSource != null
&& resolvedTableSource.findColumn(alias_hash) != null) {
return true;
}
return false;
}
return ((SQLPropertyExpr) expr).nameHashCode64() == alias_hash;
}
return false;
}
public String toString() {
String dbType = null;
if (parent instanceof OracleSQLObject) {
dbType = JdbcConstants.ORACLE;
}
return SQLUtils.toSQLString(this, dbType);
}
}