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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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 * Copyright 2001 (C) Intalio, Inc. All Rights Reserved.
 *
 * 
 */


package org.exolab.castor.xml.schema;

import org.exolab.castor.xml.*;
import org.exolab.castor.xml.validators.ValidationUtils;

import java.util.Enumeration;
import java.util.Vector;
import java.util.Hashtable;

/**
 * The base class for the XML Schema Identity Constraints 
 * (key, keyref, unique).
 *
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version  
**/
public abstract class IdentityConstraint extends Annotated {
    
	//----------------/
	//Attributes
	//---------------/
    
	public static final String ATTR_ID = "id";
	
	public static final String ATTR_NAME = "xpath";
	
	public static final String ATTR_SELECTOR = "selector";
	
    /**
     * Identity Constraint id
    **/
    private String _id   = null;
    
    /**
     * Identity Constraint name
    **/
    private String _name = null;
    
    /**
     * Identity Constraint Selector
    **/
    private IdentitySelector _selector = null;
    
    /**
     * The fields of this Identity Constraint
    **/
    private Vector _fields = null;
    
    /**
     * Constructor used by sub-classes. Creates a new IdentityConstraint.
     *
     * @param name, the name for the IdentityConstraint. Must not be null.
    **/
    protected IdentityConstraint(String name) 
        throws SchemaException
    {
        setName(name);
        _fields = new Vector(3);
    } //-- IdentityConstraint

    /**
     * Adds the given IdentityField to this IdentityConstraint
     *
     * @param field the IdentityField to add.
    **/
    public void addField(IdentityField field) {
        if (field != null) {
            _fields.addElement(field);
            //set parent
            field.setParent(this);
            
            //fire event
            fireStructureAdded(field);
        }
    } //-- addField
    
    /**
     * Returns an Enumeration of the IdentityFields contained within this
     * IdentityConstraint. 
     *
     * @return an Enumeration of the IdentityField objects contain within
     * this IdentityConstraint.
    **/
    public Enumeration getFields() {
        return _fields.elements();
    } //-- getFields
    
    /**
     * Returns the Id of this IdentityConstraint, or null if no
     * Id has been set.
     *
     * @return the Id of this IdentityConstraint, or null if no
     * Id has been set.
    **/
    public String getId() {
        return _id;
    } //-- getId
    
    /**
     * Returns the name of this IdentityConstraint. This value will
     * never be null.
     *
     * @return the name of this IdentityConstraint
    **/
    public String getName() {
        return _name;
    } //-- getName

    /**
     * Returns the selector of this IdentityConstraint. 
     *
     * @return the IdentitySelector of this IdentityConstraint
    **/
    public IdentitySelector getSelector() {
        return _selector;
    } //-- getSelector
    
    /**
     * Removes the given IdentityField from this IdentityConstraint.
     *
     * @return true if the IdentityField was contained within this 
     * IdentityConstraint, otherwise false.
    **/
    public boolean removeField(IdentityField field) {
        boolean removed = false;
    	if(_fields.contains(field)) {
    		removed = true;
        	_fields.removeElement(field);
        	field.setParent(null);
        	
        	//fire event 
        	fireStructureRemoved(field);
        }
    	return removed;
    } //-- removeField
    
     
    /**
     * Sets the Id for this IdentityConstraint.
     *
     * @param id the Id for this IdentityConstraint. 
    **/
    public void setId(String id) {
    	String oldValue = _id;
        _id = id;
        
        //fire event
        fireAttributeEvent(ATTR_ID, oldValue, id);
    } //-- setId
    
    /**
     * Sets the name for this IdentityConstraint.
     *
     * @param name the name for this IdentityConstraint. Must not be null.
     * @exception SchemaException if name is null.
    **/
    public void setName(String name) 
        throws SchemaException
    {
        if (name == null) 
            throw new SchemaException("The name of an IdentityConstraint must not be null.");
            
        String oldValue = _name;
        _name = name;
        
        //fire event
        fireAttributeEvent(ATTR_NAME, oldValue, name);
    } //-- setName
    
    /**
     * Sets the selector for this IdentityConstraint.
     *
     * @param selector the Selector for this IdentityConstraint. Must not be 
     * null.
     * @exception SchemaException if selector is null.
    **/
    public void setSelector(IdentitySelector selector) 
        throws SchemaException
    {
        if (selector == null) 
            throw new SchemaException("The selector of an IdentityConstraint must not be null.");
        IdentitySelector oldValue = _selector;
        _selector = selector;
        
        //set parent
        _selector.setParent(selector);
        
        //fire event
        fireAttributeEvent(ATTR_SELECTOR, oldValue, selector);
    } //-- setSelector
    
    /**
     * Returns the type of this Schema Structure
     * @return the type of this Schema Structure
    **/
    public abstract short getStructureType();

    /**
     * Checks the validity of this Schema defintion.
     * @exception ValidationException when this Schema definition
     * is invalid.
    **/
    public void validate()
        throws ValidationException
    {
        String err = null;
        
        //-- name must be a NCName
        if (!ValidationUtils.isNCName(_name)) {
            err = "The name of an IdentityConstraint must be an NCName.";
        }
        //-- selector must exist
        else if (_selector == null) {
            err = "Selector for IdentityConstraint cannot be null.";
        }
        //-- at least 1 (one) field must exist
        else if (_fields.size() < 1) {
            err = "There must be at least one 'field' in an "
                + "identity constraint.";
        }
        
        if (err != null) throw new ValidationException(err);
        
    } //-- validate
    
} //-- class IdentityConstraint