//$Id: Constraint.java 10661 2006-10-31 02:19:13Z epbernard $package org.hibernate.mapping;import java.io.Serializable;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import org.hibernate.dialect.Dialect;import org.hibernate.engine.Mapping;/** * A relational constraint. * * @author Gavin King */public abstract class Constraint implements RelationalModel, Serializable {	private String name;	private final List 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 columnIterator) {		while ( columnIterator.hasNext() ) {			Selectable col = (Selectable) columnIterator.next();			if ( !col.isFormula() ) addColumn( (Column) col );		}	}	/**	 * @param column	 * @return true if this constraint already contains a column with same name.	 */	public boolean containsColumn(Column column) {		return columns.contains( column );	}	public int getColumnSpan() {		return columns.size();	}	public Column getColumn(int i) {		return (Column) columns.get( i );	}	public Iterator columnIterator() {		return columns.iterator();	}	public Table getTable() {		return table;	}	public void setTable(Table table) {		this.table = table;	}	public boolean isGenerated(Dialect dialect) {		return true;	}	public String sqlDropString(Dialect dialect, String defaultCatalog, String defaultSchema) {		if ( isGenerated( dialect ) ) {			return "alter table " + getTable()					.getQualifiedName( dialect, defaultCatalog, defaultSchema ) + " drop constraint " + getName();		}		else {			return null;		}	}	public String sqlCreateString(Dialect dialect, Mapping p, String defaultCatalog, String defaultSchema) {		if ( isGenerated( dialect ) ) {			String constraintString = sqlConstraintString( dialect, getName(), defaultCatalog, defaultSchema );			StringBuffer buf = new StringBuffer( "alter table " )					.append( getTable().getQualifiedName( dialect, defaultCatalog, defaultSchema ) )					.append( constraintString );			return buf.toString();		}		else {			return null;		}	}	public List getColumns() {		return columns;	}	public abstract String sqlConstraintString(Dialect d, String constraintName, String defaultCatalog,											   String defaultSchema);	public String toString() {		return getClass().getName() + '(' + getTable().getName() + getColumns() + ") as " + name;	}}