org.apache.empire.db.DBIndex 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 org.apache.empire.exceptions.InvalidArgumentException;
/**
* This class handles the primary key for the tables.
* The primary key contains one or more columns.
*
*
*
*/
public class DBIndex extends DBObject
{
private final static long serialVersionUID = 1L;
// Index Types
/**
* SQL Standard index
*/
public static final int STANDARD = 0;
/**
* SQL Unique index
*/
public static final int UNIQUE = 1;
/**
* SQL Primary key index
*/
public static final int PRIMARYKEY = 2;
private String name;
private int type;
private DBColumn[] columns;
private DBTable table;
/**
* Constructs a DBIndex object set the specified parameters to this object.
*
* @param name the primary key name
* @param type the primary key type (only PRIMARYKEY)
* @param columns an array of one or more columns of the primary key
*/
public DBIndex(String name, int type, DBColumn[] columns)
{
this.name = name;
this.type = type;
this.columns = columns;
}
/**
* returns the table this index belongs to.
* Valid only if the index has been added to a table (DBTable.addIndex)
* @return the corresponding table
*/
public DBTable getTable()
{
return table;
}
/**
* internally used to set the table for this index.
* The table must be added to the table's index list beforehand
* @param table
*/
void setTable(DBTable table)
{
if (table==null || !table.getIndexes().contains(this))
throw new InvalidArgumentException("table", table);
// table
this.table = table;
}
@Override
public DBDatabase getDatabase()
{
return (table!=null) ? table.getDatabase() : null;
}
/**
* Returns the primary key name.
*
* @return the primary key name
*/
public String getName()
{
return name;
}
/**
* Returns the columns belonging to this index.
*
* @return the columns belonging to this index
*/
public DBColumn[] getColumns()
{
return columns;
}
/**
* Returns the columnExpressions belonging to this index.
*
* @return the columnExpressions belonging to this index
*/
public DBExpr[] getExpressions()
{
return columns;
}
/**
* Returns the full qualified table name.
*
* @return the full qualified table name
*/
public String getFullName()
{
String schema = getDatabase().getSchema();
return (schema!=null) ? schema+"."+name : name;
}
/**
* Returns the index type.
*
* @return the type of this index ({@link #PRIMARYKEY}, {@link #UNIQUE}, {@link #STANDARD})
*/
public int getType()
{
return type;
}
/**
* Checks if this index contains the column col
*
* @param col the column
*
* @return true if this index contains this column
*/
public boolean contains(DBColumn col)
{
for (int i = 0; i < columns.length; i++)
if (col.equals(columns[i]))
return true;
return false;
}
/**
* Gets the position of a specified DBColumn object.
*
* @param col the column
*
* @return the position or -1 if the column was not found
*/
public int getColumnPos(DBColumn col)
{
for (int i = 0; i < columns.length; i++)
if (col.equals(columns[i]))
return i;
return -1;
}
}