org.apache.empire.db.expr.compare.DBCompareColExpr 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.expr.compare;
// java
import org.apache.empire.db.DBCmpType;
import org.apache.empire.db.DBColumn;
import org.apache.empire.db.DBColumnExpr;
import org.apache.empire.db.DBDatabase;
import org.apache.empire.db.DBExpr;
import java.util.Set;
/**
* This class is used for defining filter constraints based on a column expression in SQL
*
* There is no need to explicitly create instances of this class.
* Instead use any of the following functions:
* {@link DBColumnExpr#is(Object) }, {@link DBColumnExpr#isBetween(Object, Object) }, {@link DBColumnExpr#isGreaterThan(Object) },
* {@link DBColumnExpr#isLessOrEqual(Object) }, {@link DBColumnExpr#isMoreOrEqual(Object) }, {@link DBColumnExpr#isNot(Object) },
* {@link DBColumnExpr#isNotBetween(Object, Object) }, {@link DBColumnExpr#isSmallerThan(Object) }, {@link DBColumnExpr#like(Object) },
* {@link DBColumnExpr#like(String, char) }, {@link DBColumnExpr#likeLower(String) }, {@link DBColumnExpr#likeUpper(String) }
*
*
*/
public class DBCompareColExpr extends DBCompareExpr
{
private final static long serialVersionUID = 1L;
protected final DBColumnExpr expr;
protected final DBCmpType cmpop;
protected Object value;
/**
* Constructs a DBCompareColExpr object set the specified parameters to this object.
*
* @param expr the DBColumnExpr object
* @param op the comparative context e.g. (CMP_EQUAL, CMP_SMALLER)
* @param value the comparative value
*/
public DBCompareColExpr(DBColumnExpr expr, DBCmpType op, Object value)
{
this.expr = expr;
this.cmpop = op;
this.value = value;
}
/**
* Returns the current DBDatabase object.
*
* @return the current DBDatabase object
*/
@Override
public DBDatabase getDatabase()
{
return expr.getDatabase();
}
/**
* Gets the DBColumnExpr object
* @return the DBColumnExpr object
*/
public DBColumnExpr getColumnExpr()
{
return expr;
}
/**
* Gets the comparison operator
* @return the comparison operator
*/
public DBCmpType getCmpop()
{
return cmpop;
}
/**
* Gets the value to compare the column expression with
* @return the value to compare the column expression with
*/
public Object getValue()
{
return value;
}
/**
* The value to compare the column expression with
* @param value the comparison value
*/
public void setValue(Object value)
{
this.value = value;
}
/**
* @see org.apache.empire.db.DBExpr#addReferencedColumns(Set)
*/
@Override
public void addReferencedColumns(Set list)
{ // return all Columns
expr.addReferencedColumns(list);
// Check if Value is a Column Expression
if (value instanceof DBExpr)
((DBExpr)value).addReferencedColumns(list);
}
/**
* Add the comparison operator and value to the SQL-Command.
*
* @param buf the SQL-Command
* @param context the comparative context e.g. (CMP_EQUAL, CMP_SMALLER)
*/
public void addCompareExpr(StringBuilder buf, long context)
{ // Assemble expression
String arraySep = "+";
DBCmpType op = cmpop;
switch (op)
{ // other than default:
case BETWEEN:
case NOTBETWEEN:
arraySep = " AND ";
break;
case IN:
case NOTIN:
arraySep = ", ";
break;
default:
// Nothing to do
break;
}
// Value
String valsql = getObjectValue(expr.getDataType(), value, context, arraySep);
if (valsql == null || valsql.equalsIgnoreCase("null"))
{ // Null oder Not Null!
op = DBCmpType.getNullType(op);
}
// Add comparison operator and value
switch (op)
{
case EQUAL:
buf.append("=");
break;
case NOTEQUAL:
buf.append("<>");
break;
case LESSTHAN:
buf.append("<");
break;
case MOREOREQUAL:
buf.append(">=");
break;
case GREATERTHAN:
buf.append(">");
break;
case LESSOREQUAL:
buf.append("<=");
break;
case LIKE:
buf.append(" LIKE ");
break;
case NOTLIKE:
buf.append(" NOT LIKE ");
break;
case NULL:
buf.append(" IS NULL");
valsql = null;
break;
case NOTNULL:
buf.append(" IS NOT NULL");
valsql = null;
break;
case BETWEEN:
buf.append(" BETWEEN ");
break;
case NOTBETWEEN:
buf.append(" NOT BETWEEN ");
break;
case IN:
buf.append(" IN (");
buf.append(valsql);
buf.append(")");
valsql = null;
break;
case NOTIN:
buf.append(" NOT IN (");
buf.append(valsql);
buf.append(")");
valsql = null;
break;
default:
// NONE
buf.append(" ");
}
if (valsql != null)
buf.append(valsql);
}
/**
* Creates the SQL-Command.
*
* @param buf the SQL-Command
* @param context the current SQL-Command context
*/
@Override
public void addSQL(StringBuilder buf, long context)
{
// Name Only ?
if ((context & CTX_VALUE) == 0)
{
expr.addSQL(buf, context);
return;
}
// Value Only ?
if ((context & CTX_NAME) == 0)
{
String valsql = getObjectValue(expr.getDataType(), value, context, "+");
buf.append((valsql != null) ? valsql : "null");
return;
}
// Add Compare Expression
expr.addSQL(buf, context);
addCompareExpr(buf, context);
}
/**
* Returns whether the constraint should replace another one or not.
*
* @return true it the constraints are mutually exclusive or false otherwise
*/
@Override
public boolean isMutuallyExclusive(DBCompareExpr other)
{
if (other instanceof DBCompareColExpr)
{
DBCompareColExpr o = (DBCompareColExpr)other;
DBColumnExpr oexpr = o.getColumnExpr();
if (expr.equals(oexpr))
return true;
DBColumn col = expr.getUpdateColumn();
DBColumn ocol = oexpr.getUpdateColumn();
return (col!=null) ? (col.equals(ocol)) : false;
}
return false;
}
}