Package com.mckoi.database

Class JoiningSet

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable
    public final class JoiningSet
extends java.lang.Object
implements java.io.Serializable, java.lang.Cloneable
    Used in TableSet to describe how we naturally join the tables together. This is used when the TableSet has evaluated the search condition and it is required for any straggling tables to be naturally joined. In SQL, these joining types are specified in the FROM clause.

    For example,

       FROM table_a LEFT OUTER JOIN table_b ON ( table_a.id = table_b.id ), ...

    A ',' should donate an INNER_JOIN in an SQL FROM clause.

    Author:
    Tobias Downer
    See Also:
    Serialized Form

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  JoiningSet.JoinPart  

    • Constructor Summary

      Constructors 
      Constructor Description
      JoiningSet()
      Constructs the JoiningSet.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void addJoin​(int type)
      Adds a joining type to the set with no 'on' expression.
      void addJoin​(int type, Expression on_expression)
      Adds a joining type to the set, and an 'on' expression.
      void addPreviousJoin​(int type, Expression on_expression)
      Hack, add a joining type to the previous entry from the end.
      void addTable​(TableName table_name)
      Adds a new table into the set being joined.
      java.lang.Object clone()
      Performs a deep clone on this object.
      TableName getFirstTable()
      Returns the first table in the join set.
      int getJoinType​(int n)
      Returns the type of join after table 'n' in the set.
      Expression getOnExpression​(int n)
      Returns the ON Expression for the type of join after table 'n' in the set.
      TableName getTable​(int n)
      Returns table 'n' in the result set where table 0 is the first table in the join set.
      int getTableCount()
      Returns the number of tables that are in this set.
      void prepare​(DatabaseConnection connection)
      Resolves the schema of tables in this joining set.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • JoiningSet

        public JoiningSet()
        Constructs the JoiningSet.

    • Method Detail

      • prepare

        public void prepare​(DatabaseConnection connection)
        Resolves the schema of tables in this joining set. This runs through each table in the joining set and if the schema has not been set for the table then it attempts to resolve it against the given DatabaseConnection object. This would typically be called in the preparation of a statement.

      • addTable

        public void addTable​(TableName table_name)
        Adds a new table into the set being joined. The table name should be the unique name that distinguishes this table in the TableSet.

      • addPreviousJoin

        public void addPreviousJoin​(int type,
                            Expression on_expression)
        Hack, add a joining type to the previous entry from the end. This is an artifact of how joins are parsed.

      • addJoin

        public void addJoin​(int type,
                    Expression on_expression)
        Adds a joining type to the set, and an 'on' expression.

      • addJoin

        public void addJoin​(int type)
        Adds a joining type to the set with no 'on' expression.

      • getTableCount

        public int getTableCount()
        Returns the number of tables that are in this set.

      • getFirstTable

        public TableName getFirstTable()
        Returns the first table in the join set.

      • getTable

        public TableName getTable​(int n)
        Returns table 'n' in the result set where table 0 is the first table in the join set.

      • getJoinType

        public int getJoinType​(int n)
        Returns the type of join after table 'n' in the set. An example of using this;

        
 String table1 = joins.getFirstTable();
 for (int i = 0; i < joins.getTableCount() - 1; ++i) {
   int type = joins.getJoinType(i);
   String table2 = getTable(i + 1);
   // ... Join table1 and table2 ...
   table1 = table2;
 }

      • getOnExpression

        public Expression getOnExpression​(int n)
        Returns the ON Expression for the type of join after table 'n' in the set.

      • clone

        public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException
        Performs a deep clone on this object.
        Overrides:
        clone in class java.lang.Object
        Throws:
        java.lang.CloneNotSupportedException