org.apache.empire.db.DBCombinedCmd Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.empire.db;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.apache.empire.data.DataType;
import org.apache.empire.db.expr.order.DBOrderByExpr;
/**
* This class is used for building up a partition of a SQL-Command.
* It handles the insert from a specified key word between two DBCommandExpr objects.
*
*
*
*/
public class DBCombinedCmd extends DBCommandExpr
{
// *Deprecated* private static final long serialVersionUID = 1L;
// Members
protected DBCommandExpr left;
protected DBCommandExpr right;
protected String keyWord;
/**
* Constructs a new DBFuncExpr object and
* sets the specified parameters to this object.
*
* @param left the first DBCommandExpr object
* @param keyWord the key word between the two DBCommandExpr objects
* @param right the second DBCommandExpr object
*/
public DBCombinedCmd(DBCommandExpr left, String keyWord, DBCommandExpr right)
{
super(left.getDbms());
this.left = left;
this.right = right;
this.keyWord = keyWord;
}
@Override
public boolean isValid()
{
return (left.isValid() && right.isValid());
}
/**
* Returns the current DBDatabase object.
*
* @return the current DBDatabase object
*/
@SuppressWarnings("unchecked")
@Override
public final DBDatabase getDatabase()
{
return left.getDatabase();
}
/**
* @see org.apache.empire.db.DBExpr#addReferencedColumns(Set)
*/
@Override
public void addReferencedColumns(Set list)
{
left.addReferencedColumns(list);
right.addReferencedColumns(list);
}
/**
* returns whether or not the command has any select expression
* @return true if the command has any select expression of false otherwise
*/
@Override
public boolean hasSelectExpr()
{
return left.hasSelectExpr();
}
/**
* returns whether or not the command has a specific select expression
* @return true if the command contains the given select expression of false otherwise
*/
@Override
public boolean hasSelectExpr(DBColumnExpr expr)
{
return left.hasSelectExpr(expr);
}
/**
* Returns all select expressions as unmodifiable list
* @return the list of DBColumnExpr used for select
*/
@Override
public List getSelectExpressions()
{
return left.getSelectExpressions();
}
/**
* Calls the method dbDBCommandExpr.getSelectExprList from the private variable 'left'.
* Returns a array of all DBColumnExpr object of the Vector: 'select'.
*
* @see org.apache.empire.db.DBCommandExpr#getSelectExprList()
* @return returns an array of all DBColumnExpr object of the Vector: 'select'
*/
@Override
public DBColumnExpr[] getSelectExprList()
{
// DebugMsg(2, "Check: getSelectExprList() for DBCombinedCmd");
return left.getSelectExprList();
}
@Override
public DBCmdParams getParams()
{
DBCmdParams lp = left.getParams();
DBCmdParams rp = right.getParams();
if (lp.isEmpty())
return rp;
if (rp.isEmpty())
return lp;
// combine
DBCmdParams params = new DBCmdParams() {
final ArrayList list = new ArrayList(lp.size()+rp.size());
{
for (DBCmdParam p : lp)
list.add(p);
for (DBCmdParam p : rp)
list.add(p);
}
@Override
public boolean isEmpty() {
return list.isEmpty();
}
@Override
public int size() {
return list.size();
}
@Override
public Iterator iterator() {
return list.iterator();
}
};
return params;
}
/**
* Returns the list of parameter values for a prepared statement.
* To ensure the correct order, getSelect() must be called first.
* @return the list of parameter values for a prepared statement
*/
@Override
public Object[] getParamValues()
{
Object[] leftParams = left.getParamValues();
Object[] rightParams = right.getParamValues();
// Check
if (leftParams == null)
return rightParams;
if (rightParams == null)
return leftParams;
// Put them all together
Object[] allParams = new Object[leftParams.length + rightParams.length];
for (int i = 0; i < leftParams.length; i++)
allParams[i] = leftParams[i];
for (int i = 0; i < rightParams.length; i++)
allParams[leftParams.length + i] = rightParams[i];
// return Params
return allParams;
}
/**
* @return the DataType of the selected expression or DataType.UNKNOWN
*/
@Override
public DataType getDataType()
{
return left.getDataType();
}
/**
* Creates the SQL-Command.
*
* @param sql the SQL-Command
*/
@Override
public void getSelect(DBSQLBuilder sql)
{
// the left part
left.clearOrderBy();
if (!(left instanceof DBCombinedCmd))
{
sql.append("(");
left.getSelect(sql);
sql.append(")");
}
else
left.getSelect(sql);
// concat keyword
sql.append("\r\n");
sql.append(keyWord);
sql.append("\r\n");
// the right part
right.clearOrderBy();
if (!(right instanceof DBCombinedCmd))
{
sql.append("(");
right.getSelect(sql);
sql.append(")");
}
else
right.getSelect(sql);
// done
// Add optional Order by statement
if (orderBy != null)
{ // Having
sql.append("\r\nORDER BY ");
addListExpr(sql, orderBy, CTX_DEFAULT, ", ");
}
}
@Override
public DBCommandExpr orderBy(DBOrderByExpr... exprs)
{
if (orderBy == null)
orderBy = new ArrayList();
// Add order by expression
for (DBOrderByExpr obe : exprs)
{
DBColumnExpr c = getCmdColumn(obe.getColumn());
orderBy.add(new DBOrderByExpr(c, obe.isDescending()));
}
return this;
}
}