//$Id: Constraint.java,v 1.5.2.5 2003/12/01 05:29:15 oneovthafew Exp $package net.sf.hibernate.mapping;import java.util.ArrayList;import java.util.Iterator;import net.sf.hibernate.dialect.Dialect;import net.sf.hibernate.engine.Mapping;/** * A relational constraint. * @author Gavin King */public abstract class Constraint implements RelationalModel {		private String name;	private final ArrayList columns = new ArrayList();	private Table table;		public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public Iterator getColumnIterator() {		return columns.iterator();	}	public void addColumn(Column column) {		if ( !columns.contains(column) ) columns.add(column);	}	public void addColumns(Iterator columns) {		while ( columns.hasNext() ) addColumn( (Column) columns.next() );	}	public int getColumnSpan() {		return columns.size();	}	public Iterator columnIterator() {		return columns.iterator();	}	public Table getTable() {		return table;	}	public void setTable(Table table) {		this.table = table;	}		public String sqlDropString(Dialect dialect) {		return "alter table " + getTable().getQualifiedName(dialect) + " drop constraint " + getName();	}		public String sqlCreateString(Dialect dialect, Mapping p) {		StringBuffer buf = new StringBuffer("alter table ")		.append( getTable().getQualifiedName(dialect) )		.append( sqlConstraintString( dialect, getName() ) );		return buf.toString();	}		public abstract String sqlConstraintString(Dialect d, String constraintName);}