empire-db/src/main/java/org/apache/empire/db/expr/join/DBColumnJoinExpr.java - empire-db - Git at Google

 /*
  * 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.expr.join;

 import java.util.HashSet;
 import java.util.Set;

 import org.apache.empire.db.DBColumn;
 import org.apache.empire.db.DBColumnExpr;
 import org.apache.empire.db.DBCommand;
 import org.apache.empire.db.DBDatabase;
 import org.apache.empire.db.DBJoinType;
 import org.apache.empire.db.DBQuery;
 import org.apache.empire.db.DBRowSet;
 import org.apache.empire.db.expr.compare.DBCompareExpr;
 import org.apache.empire.exceptions.InvalidPropertyException;

 public class DBColumnJoinExpr extends DBJoinExpr
 {
     // *Deprecated* private static final long serialVersionUID = 1L;

     protected DBColumnExpr  left;
     protected DBColumnExpr  right;

     // Additional
     public DBCompareExpr compExpr = null;

     /**
      * Constructs a new DBJoinExpr object initialize this object with
      * the left and right column and the data type of the join
      * expression.
      *
      * @param left left value
      * @param right right value
      * @param type data type (JOIN_INNER, JOIN_LEFT or JOIN_RIGHT)
      */
     public DBColumnJoinExpr(DBColumnExpr left, DBColumnExpr right, DBJoinType type)
     {
         super(type);
         this.left = left;
         this.right = right;
     }

     /**
      * Returns the current DBDatabase object.
      *
      * @return the current DBDatabase object
      */
     @SuppressWarnings("unchecked")
     @Override
     public final DBDatabase getDatabase()
     {
         return left.getDatabase();
     }

     /**
      * returns the left join expression
      */
     public DBColumnExpr getLeft()
     {
         return left;
     }

     /**
      * returns the right join expression
      */
     public DBColumnExpr getRight()
     {
         return right;
     }

     @Override
     public DBRowSet getLeftTable()
     {
         DBColumn col = left.getSourceColumn();
         if (col==null)
             throw new InvalidPropertyException("left", left);
         return col.getRowSet();
     }

     /**
      * returns the RowSet on the right of the join
      */
     @Override
     public DBRowSet getRightTable()
     {
         DBColumn col = right.getSourceColumn();
         if (col==null)
             throw new InvalidPropertyException("right", right);
         return col.getRowSet();
     }

     /**
      * returns true if this join is using the given table or view or false otherwise
      */
     @Override
     public boolean isJoinOn(DBRowSet rowset)
     {
         if (rowset==null)
             return false;
         // compare rowsets
         return rowset.equals(getLeftTable()) || rowset.equals(getRightTable());
     }

     /**
      * returns true if this join is using the given column or false otherwise
      */
     @Override
     public boolean isJoinOn(DBColumn column)
     {
         if (column==null)
             return false;
         // Check Update Columns
         if (column.equals(left.getSourceColumn()) ||
             column.equals(right.getSourceColumn()))
             return true;
         if (compExpr!=null)
         {   // Check expression
             HashSet<DBColumn> set = new HashSet<DBColumn>();
             compExpr.addReferencedColumns(set);
             return set.contains(column);
         }
         // not found
         return false;
     }

     /**
      * Returns the left table name if the data type= JOIN_LEFT and returns
      * the right table if the data type= JOIN_RIGHT. If the
      * data type = JOIN_INNER the return value is null.
      *
      * @return the current DBDatabase object
      */
     @Override
     public DBRowSet getOuterTable()
     {
         switch(type)
         {
             case LEFT:  return getRightTable();
             case RIGHT: return getLeftTable();
             default:    return null; // no outer table!
         }
     }

     /**
      * This function swaps the left and the right statements of the join expression.
      */
     @Override
     public void reverse()
     { // Swap Type of Join
         DBColumnExpr swap = left;
         left = right;
         right = swap;
         type = DBJoinType.reversed(type); // (type * -1);
     }

     /**
      * Copy Command
      * @param cmd
      */
     @Override
     public DBJoinExpr copy(DBCommand newCmd)
     {   // check additional compare expr
         if (this.compExpr==null)
             return this; // not necessary
         // Copy compareExpr
         DBColumnJoinExpr join = new DBColumnJoinExpr(left, right, type);
         join.compExpr = compExpr.copy(newCmd);
         return join;
     }

     /**
      * Returns any additional constraints to the join
      * @return a compare expression containing additional constraints or null
      */
     public DBCompareExpr getWhere()
     {
         return compExpr;
     }

     /**
      * This function adds an additional constraint to the join.
      *
      * @param expr the compare expression
      */
     public void where(DBCompareExpr expr)
     { // Set Compare Expression
         compExpr = expr;
     }

     /**
      * This function adds an additional constraint to the join.
      *
      * @param c1 the first column
      * @param c2 the second column
      *
      * @return the object itself
      */
     public DBJoinExpr and(DBColumnExpr c1, DBColumnExpr c2)
     {   // Set Compare Expression
         if (compExpr==null)
             compExpr = c1.is(c2);
         else
             compExpr = compExpr.and(c1.is(c2));
         return this;
     }

     /**
      * @see org.apache.empire.db.DBExpr#addReferencedColumns(Set)
      */
     @Override
     public void addReferencedColumns(Set<DBColumn> list)
     {
         left.addReferencedColumns(list);
         right.addReferencedColumns(list);
         // Compare Expression
         if (compExpr != null)
             compExpr.addReferencedColumns(list);
     }

     /** Not allowed, this operation have to be done in the DBCommand object. */
     @Override
     public void addSQL(StringBuilder buf, long context)
     {
         // left
         if ((context & CTX_NAME) != 0)
             getLeftTable().addSQL(buf, CTX_DEFAULT | CTX_ALIAS);
         if ((context & CTX_VALUE) != 0)
         { // Join Type
             switch(type)
             {
                 case LEFT:  buf.append(" LEFT JOIN ");break;
                 case INNER: buf.append(" INNER JOIN ");break;
                 case RIGHT: buf.append(" RIGHT JOIN ");break;
                 case FULL:  buf.append(" FULL JOIN ");break;
                 default:    buf.append(" JOIN "); // should not come here!
             }
             getRightTable().addSQL(buf, CTX_DEFAULT | CTX_ALIAS);
             // compare equal
             buf.append(" ON ");
             right.addSQL(buf, CTX_DEFAULT);
             buf.append(" = ");
             left.addSQL(buf, CTX_DEFAULT);
             // Compare Expression
             if (compExpr != null)
             {
                 buf.append(" AND ");
                 compExpr.addSQL(buf, CTX_DEFAULT);
             }
         }
     }

     /**
      * Returns the subquery Params
      * Valid only directly after addSQL() has been called!
      * @param which: both (==0) | left (<=0) | right (>=0)
      * @return the subquery params;
      */
     @Override
     public Object[] getSubqueryParams(int which)
     {
         DBRowSet left = getLeftTable();
         DBRowSet right = getRightTable();
         Object[] leftParams  = (which<=0 && (left  instanceof DBQuery)) ? ((DBQuery)left ).getCommandExpr().getParamValues() : null;
         Object[] rightParams = (which>=0 && (right instanceof DBQuery)) ? ((DBQuery)right).getCommandExpr().getParamValues() : null;
         if (leftParams!=null && rightParams!=null)
         {   // combine
             Object[] both = new Object[leftParams.length+rightParams.length];
             int index = 0;
             for (int i=0; i<leftParams.length; i++)
                 both[index++] = leftParams[i];
             for (int i=0; i<rightParams.length; i++)
                 both[index++] = rightParams[i];
             return both;
         }
         return (leftParams!=null ? leftParams : rightParams);
     }

     /**
      * Compares two DBJoinExpr objects.
      *
      * @param obj other DBJoinExpr object
      * @return true if the other DBJoinExpr object is equal to this object
      */
     @Override
     public boolean equals(Object obj)
     {
         if (!(obj instanceof DBColumnJoinExpr))
             return super.equals(obj);
         // object
         DBColumnJoinExpr other = (DBColumnJoinExpr) obj;
         if (left.equals(other.left) && right.equals(other.right) && type == other.type)
             return true;
         // reversed
         if (left.equals(other.right) && right.equals(other.left) && type == DBJoinType.reversed(other.type))
             return true;
         // not equal
         return false;
     }

 }
	/*
	* 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.expr.join;

	import java.util.HashSet;
	import java.util.Set;

	import org.apache.empire.db.DBColumn;
	import org.apache.empire.db.DBColumnExpr;
	import org.apache.empire.db.DBCommand;
	import org.apache.empire.db.DBDatabase;
	import org.apache.empire.db.DBJoinType;
	import org.apache.empire.db.DBQuery;
	import org.apache.empire.db.DBRowSet;
	import org.apache.empire.db.expr.compare.DBCompareExpr;
	import org.apache.empire.exceptions.InvalidPropertyException;

	public class DBColumnJoinExpr extends DBJoinExpr
	{
	// Deprecated private static final long serialVersionUID = 1L;

	protected DBColumnExpr left;
	protected DBColumnExpr right;

	// Additional
	public DBCompareExpr compExpr = null;

	/**
	* Constructs a new DBJoinExpr object initialize this object with
	* the left and right column and the data type of the join
	* expression.
	*
	* @param left left value
	* @param right right value
	* @param type data type (JOIN_INNER, JOIN_LEFT or JOIN_RIGHT)
	*/
	public DBColumnJoinExpr(DBColumnExpr left, DBColumnExpr right, DBJoinType type)
	{
	super(type);
	this.left = left;
	this.right = right;
	}

	/**
	* Returns the current DBDatabase object.
	*
	* @return the current DBDatabase object
	*/
	@SuppressWarnings("unchecked")
	@Override
	public final DBDatabase getDatabase()
	{
	return left.getDatabase();
	}

	/**
	* returns the left join expression
	*/
	public DBColumnExpr getLeft()
	{
	return left;
	}

	/**
	* returns the right join expression
	*/
	public DBColumnExpr getRight()
	{
	return right;
	}

	@Override
	public DBRowSet getLeftTable()
	{
	DBColumn col = left.getSourceColumn();
	if (col==null)
	throw new InvalidPropertyException("left", left);
	return col.getRowSet();
	}

	/**
	* returns the RowSet on the right of the join
	*/
	@Override
	public DBRowSet getRightTable()
	{
	DBColumn col = right.getSourceColumn();
	if (col==null)
	throw new InvalidPropertyException("right", right);
	return col.getRowSet();
	}

	/**
	* returns true if this join is using the given table or view or false otherwise
	*/
	@Override
	public boolean isJoinOn(DBRowSet rowset)
	{
	if (rowset==null)
	return false;
	// compare rowsets
	return rowset.equals(getLeftTable()) \|\| rowset.equals(getRightTable());
	}

	/**
	* returns true if this join is using the given column or false otherwise
	*/
	@Override
	public boolean isJoinOn(DBColumn column)
	{
	if (column==null)
	return false;
	// Check Update Columns
	if (column.equals(left.getSourceColumn()) \|\|
	column.equals(right.getSourceColumn()))
	return true;
	if (compExpr!=null)
	{ // Check expression
	HashSet<DBColumn> set = new HashSet<DBColumn>();
	compExpr.addReferencedColumns(set);
	return set.contains(column);
	}
	// not found
	return false;
	}

	/**
	* Returns the left table name if the data type= JOIN_LEFT and returns
	* the right table if the data type= JOIN_RIGHT. If the
	* data type = JOIN_INNER the return value is null.
	*
	* @return the current DBDatabase object
	*/
	@Override
	public DBRowSet getOuterTable()
	{
	switch(type)
	{
	case LEFT: return getRightTable();
	case RIGHT: return getLeftTable();
	default: return null; // no outer table!
	}
	}

	/**
	* This function swaps the left and the right statements of the join expression.
	*/
	@Override
	public void reverse()
	{ // Swap Type of Join
	DBColumnExpr swap = left;
	left = right;
	right = swap;
	type = DBJoinType.reversed(type); // (type * -1);
	}

	/**
	* Copy Command
	* @param cmd
	*/
	@Override
	public DBJoinExpr copy(DBCommand newCmd)
	{ // check additional compare expr
	if (this.compExpr==null)
	return this; // not necessary
	// Copy compareExpr
	DBColumnJoinExpr join = new DBColumnJoinExpr(left, right, type);
	join.compExpr = compExpr.copy(newCmd);
	return join;
	}

	/**
	* Returns any additional constraints to the join
	* @return a compare expression containing additional constraints or null
	*/
	public DBCompareExpr getWhere()
	{
	return compExpr;
	}

	/**
	* This function adds an additional constraint to the join.
	*
	* @param expr the compare expression
	*/
	public void where(DBCompareExpr expr)
	{ // Set Compare Expression
	compExpr = expr;
	}

	/**
	* This function adds an additional constraint to the join.
	*
	* @param c1 the first column
	* @param c2 the second column
	*
	* @return the object itself
	*/
	public DBJoinExpr and(DBColumnExpr c1, DBColumnExpr c2)
	{ // Set Compare Expression
	if (compExpr==null)
	compExpr = c1.is(c2);
	else
	compExpr = compExpr.and(c1.is(c2));
	return this;
	}

	/**
	* @see org.apache.empire.db.DBExpr#addReferencedColumns(Set)
	*/
	@Override
	public void addReferencedColumns(Set<DBColumn> list)
	{
	left.addReferencedColumns(list);
	right.addReferencedColumns(list);
	// Compare Expression
	if (compExpr != null)
	compExpr.addReferencedColumns(list);
	}

	/** Not allowed, this operation have to be done in the DBCommand object. */
	@Override
	public void addSQL(StringBuilder buf, long context)
	{
	// left
	if ((context & CTX_NAME) != 0)
	getLeftTable().addSQL(buf, CTX_DEFAULT \| CTX_ALIAS);
	if ((context & CTX_VALUE) != 0)
	{ // Join Type
	switch(type)
	{
	case LEFT: buf.append(" LEFT JOIN ");break;
	case INNER: buf.append(" INNER JOIN ");break;
	case RIGHT: buf.append(" RIGHT JOIN ");break;
	case FULL: buf.append(" FULL JOIN ");break;
	default: buf.append(" JOIN "); // should not come here!
	}
	getRightTable().addSQL(buf, CTX_DEFAULT \| CTX_ALIAS);
	// compare equal
	buf.append(" ON ");
	right.addSQL(buf, CTX_DEFAULT);
	buf.append(" = ");
	left.addSQL(buf, CTX_DEFAULT);
	// Compare Expression
	if (compExpr != null)
	{
	buf.append(" AND ");
	compExpr.addSQL(buf, CTX_DEFAULT);
	}
	}
	}

	/**
	* Returns the subquery Params
	* Valid only directly after addSQL() has been called!
	* @param which: both (==0) \| left (<=0) \| right (>=0)
	* @return the subquery params;
	*/
	@Override
	public Object[] getSubqueryParams(int which)
	{
	DBRowSet left = getLeftTable();
	DBRowSet right = getRightTable();
	Object[] leftParams = (which<=0 && (left instanceof DBQuery)) ? ((DBQuery)left ).getCommandExpr().getParamValues() : null;
	Object[] rightParams = (which>=0 && (right instanceof DBQuery)) ? ((DBQuery)right).getCommandExpr().getParamValues() : null;
	if (leftParams!=null && rightParams!=null)
	{ // combine
	Object[] both = new Object[leftParams.length+rightParams.length];
	int index = 0;
	for (int i=0; i<leftParams.length; i++)
	both[index++] = leftParams[i];
	for (int i=0; i<rightParams.length; i++)
	both[index++] = rightParams[i];
	return both;
	}
	return (leftParams!=null ? leftParams : rightParams);
	}

	/**
	* Compares two DBJoinExpr objects.
	*
	* @param obj other DBJoinExpr object
	* @return true if the other DBJoinExpr object is equal to this object
	*/
	@Override
	public boolean equals(Object obj)
	{
	if (!(obj instanceof DBColumnJoinExpr))
	return super.equals(obj);
	// object
	DBColumnJoinExpr other = (DBColumnJoinExpr) obj;
	if (left.equals(other.left) && right.equals(other.right) && type == other.type)
	return true;
	// reversed
	if (left.equals(other.right) && right.equals(other.left) && type == DBJoinType.reversed(other.type))
	return true;
	// not equal
	return false;
	}

	}