/*
 *                 Sun Public License Notice
 *
 * The contents of this file are subject to the Sun Public License
 * Version 1.0 (the "License"). You may not use this file except in
 * compliance with the License. A copy of the License is available at
 * http://www.sun.com/
 *
 * The Original Code is NetBeans. The Initial Developer of the Original
 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2003 Sun
 * Microsystems, Inc. All Rights Reserved.
 */

package org.netbeans.modules.tasklist.core.filter;

import javax.swing.*;
import java.awt.Component;
import org.netbeans.spi.settings.DOMConvertor;

/** 
 * A condition (type and relation pair) in the filter.
 * Don't forget to override sameType if you extend this class!
 *
 * @author Tor Norbye
 */
public abstract class FilterCondition {
    transient private String name = null;

    /**
     * Creates a condition with the given name.
     *
     * @param name user visible name of the filter condition
     */
    public FilterCondition() {
      this.name = null;
    }
    
    /**
     * Copy constructor. Use from subclassed clone.
     */
    protected FilterCondition(final FilterCondition rhs) {
        this.name = rhs.name;
    }

    /** 
     * Deep clone, please implement in subclass.
     */
    public abstract Object clone() ;
    
    /**
     * Returns the user visible name of this condition
     *
     * @return name of this condition
     */
    public String getName() {
      if (this.name == null) this.name = getDisplayName();
      return this.name;
    }
    
    /**
     * Compares two objects.
     *
     * @param obj value of the property
     */
    public abstract boolean isTrue(Object obj);

    /**
     * Creates a component that will represent a constant within the 
     * filter dialog. It should support {@link #PROP_VALUE_VALID}
     * client property.
     *
     * @return created component or null if no component 
     */
    public JComponent createConstantComponent() {
        return null;
    }

    /**
     * Gets constant from the specified component and save it.
     * This method should be also implemented if createConstantComponent()
     * is implemented.
     *
     * @param cmp with createConstantComponent() create component
     */
    public void getConstantFrom(JComponent cmp) {
        assert cmp != null : "getConstantFrom() is not implemented!";
    }

    final boolean isValueValid(JComponent cmp) {
        Boolean valid = (Boolean) cmp.getClientProperty(PROP_VALUE_VALID);
        if (valid == null) {
            return true;
        } else {
            return valid.booleanValue();
        }
    }

    /**
     * Checks whether fc is of the same type.
     * This method will be used to replace a condition created with
     * Filter.getConditionsFor(Node.Property) with one contained in a filter.
     * This method should return true also if this and fc have different 
     * constants for comparing with property values.
     *
     * @param fc another condition
     * @return true fc is of the same type as this
     */
     public boolean sameType(FilterCondition fc) {
       return fc.getClass() == getClass();
     }
    
    public String toString() {
        return getClass().getName() + 
            "[name=" + name + "]"; // NOI18N
    }

    /** Use this client property on value/contant components to indicate valid user data.*/
    public static final String PROP_VALUE_VALID = "value-valid";


    protected abstract String getDisplayName();


  /** 
   * Convertor is nested in order to have access to private fields in
   * condition. The convertor does not convert the attribute name,
   * which is locale dependent. Subclasses must remember to recover
   * this attribute when reading.
   */
  protected abstract static class Convertor extends DOMConvertor {

    /** Creates a new instance of FilerRepositoryConvertor */
    protected Convertor(String rootElement) {
      super("-//NetBeans org.netbeans.modules.tasklist//DTD" + rootElement+" 1.0//EN", // NOI18N
	    "http://tasklist.netbeans.org/dtd/conditions-1_0.dtd", rootElement); // NOI18N
    }
        
    public void registerSaver(Object obj, org.netbeans.spi.settings.Saver saver) {
      // no saver for conditions, they are immutable
    }
    
    public void unregisterSaver(Object obj, org.netbeans.spi.settings.Saver saver) {
      // no saver for conditions, they are immutable
    }
    

    protected void writeCondition(org.w3c.dom.Document document, org.w3c.dom.Element element, FilterCondition cond) 
      throws java.io.IOException, org.w3c.dom.DOMException 
    {
      // the name attribute is not convertized
    }
  
    protected void readCondition(org.w3c.dom.Element element, FilterCondition condition) 
      throws java.io.IOException, java.lang.ClassNotFoundException 
    {
      // the name attribute is not convertized
    }

  }

}