de.mguennewig.pobjects.metadata
Class NestedSetType

java.lang.Object
  de.mguennewig.pobjects.metadata.JoinType
      de.mguennewig.pobjects.metadata.NestedSetType

All Implemented Interfaces:

ReferenceToClass

public class NestedSetType
extends JoinType

Rows of the target table represent a nested set associated with the parent table.

The target table must fulfill multiple requirements that are described in setTargetClass(ClassDecl).

Author:

Michael Günnewig

Field Summary

Fields inherited from class de.mguennewig.pobjects.metadata.JoinType

CLASS_NAME, TYPE_NAME

Constructor Summary

NestedSetType(java.lang.String targetModule, java.lang.String targetName, ClassDecl targetClass, java.lang.String rightColumnName)
Initialize a nested set type.

Method Summary

Column	getLeftColumn() Returns the column that holds the left most subset.
Column	getRightColumn() Returns the column that holds the right most subset.
java.lang.String	name(int variant) Returns different names depending on variant for the code generator.
void	setTargetClass(ClassDecl te) Sets the class declaration of the referenced table.

Methods inherited from class de.mguennewig.pobjects.metadata.JoinType

getTargetClass, getTargetModule, getTargetName, setTypeClass

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NestedSetType

public NestedSetType(java.lang.String targetModule,
                     java.lang.String targetName,
                     ClassDecl targetClass,
                     java.lang.String rightColumnName)

Initialize a nested set type.

Parameters:

targetModule - Module of the target class.

targetName - The name of the class the join refers to.

targetClass - The class declaration of the referenced table. This must be given or null with a later call to setTargetClass(ClassDecl) before any usage of this type.

rightColumnName - The column that holds the right subset.

See Also:

setTargetClass(ClassDecl)

Method Detail

getLeftColumn

public final Column getLeftColumn()

Returns the column that holds the left most subset.

getRightColumn

public final Column getRightColumn()

Returns the column that holds the right most subset.

setTargetClass

public void setTargetClass(ClassDecl te)

Sets the class declaration of the referenced table.

A call to this method is only necessary if the class declaration has not been passed to the constructor to solve circle problems.

The referenced table must fulfill a couple of requirements depending on join type. The following requirements are common for all:

• requires a primary key declaration (no id field)
• the first primary key column must refer to the parent class and be defined as `on delete cascade'
• the referenced table must have more columns then just the parent reference

In addition to the generic restrictions a nested set adds the following:

• the primary key covers two columns, the second is usually referred to as left column.
• the referenced table contains the right column
• the column types of the left and right columns are integers
• the column types of the left and right columns are identically

Specified by:

setTargetClass in interface ReferenceToClass

Overrides:

setTargetClass in class JoinType

name

public java.lang.String name(int variant)

Returns different names depending on variant for the code generator.

Overrides:

name in class JoinType