DateFormatter.java

/*******************************************************************************
 * Copyright (c) 2005, 2009 Eric Wuillai.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Eric Wuillai (eric@wdev91.com) - initial API and implementation
 *******************************************************************************/
package org.eclipse.nebula.widgets.formattedtext;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Locale;

/**
 * This class provides formatting of <code>Date</code> values in a
 * <code>FormattedText</code>, restricting the edit and display to the time part.
 * Supports a subset of time patterns defined in <code>SimpleDateFormat</code>
 * for input.<p>
 * 
 * See <code>DateTimeFormatter</code> for a full description of patterns, given
 * that only patterns chars related to time are allowed.
 * 
 * <h4>Examples</h4>
 * <ul>
 * 	 <li><code>new DateFormatter("MM/dd/yyyy")</code> - 8 jul 2006 will edit and
 *   display as "07/08/2006".</li>
 *   <li><code>new DateFormatter("dd/MM/yyyy, "dd MMM yyyy")</code>- 8 jul 2006
 *   will edit as "08/07/2006" and display as "08 Jul 2006".</li>
 * </ul>
 */
public class DateFormatter  extends DateTimeFormatter {
  /**
   * Constructs a new instance with all defaults :
   * <ul>
   *   <li>edit mask in SHORT date format for the default locale</li>
   *   <li>display mask identical to the edit mask</li>
   *   <li>default locale</li>
   * </ul>
   */
	public DateFormatter() {
		super();
	}

  /**
   * Constructs a new instance with default edit and display masks for the given
   * locale.
   * 
   * @param loc locale
   */
	public DateFormatter(Locale loc) {
		super(loc);
	}

	/**
   * Constructs a new instance with the given edit mask. Display mask is
   * identical to the edit mask, and locale is the default one.
   * 
   * @param editPattern edit mask
	 */
	public DateFormatter(String editPattern) {
		super(editPattern);
	}

	/**
   * Constructs a new instance with the given edit mask and locale. Display mask
   * is identical to the edit mask.
   * 
   * @param editPattern edit mask
   * @param loc locale
	 */
	public DateFormatter(String editPattern, Locale loc) {
		super(editPattern, loc);
	}

	/**
   * Constructs a new instance with the given edit and display masks. Uses the
   * default locale.
   * 
   * @param editPattern edit mask
   * @param displayPattern display mask
	 */
	public DateFormatter(String editPattern, String displayPattern) {
		super(editPattern, displayPattern);
	}

	/**
   * Constructs a new instance with the given masks and locale.
   * 
   * @param editPattern edit mask
   * @param displayPattern display mask
   * @param loc locale
	 */
	public DateFormatter(String editPattern, String displayPattern, Locale loc) {
		super(editPattern, displayPattern, loc);
	}

	/**
   * Returns the default edit pattern for the given <code>Locale</code>.<p>
   * 
   * A <code>DateFormat</code> object is instantiated with SHORT format for
   * both the date part for the given locale. The corresponding pattern
   * string is then retrieved by calling the <code>toPattern</code>.<p>
   * 
   * Default patterns are stored in a cache with ISO3 language and country codes
   * as key. So they are computed only once by locale.
   * 
   * @param loc locale
   * @return edit pattern for the locale
   */
	public String getDefaultEditPattern(Locale loc) {
		if ( loc == null ) {
			loc = Locale.getDefault();
		}
		String key = "DA" + loc.toString();
		String pattern = (String) cachedPatterns.get(key);
		if ( pattern == null ) {
			DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, loc);
			if ( ! (df instanceof SimpleDateFormat) ) {
				throw new IllegalArgumentException("No default pattern for locale " + loc.getDisplayName());
			}
			StringBuffer buffer = new StringBuffer();
			buffer.append(((SimpleDateFormat) df).toPattern());
			int i;
			if ( buffer.indexOf("yyy") < 0 && (i = buffer.indexOf("yy")) >= 0 ) {
				buffer.insert(i, "yy");
			}
			pattern = buffer.toString();
			cachedPatterns.put(key, pattern);
		}
		return pattern;
	}

	/**
	 * Checks if a given char is valid for the edit pattern. This method
	 * overrides the parent method, restricting authorized chars to date patterns.
	 * 
	 * @param c pattern char
	 * @throws IllegalArgumentException if not valid
	 * @see DateTimeFormatter#isValidCharPattern(char)
	 */
	protected void isValidCharPattern(char c) {
		switch (c) {
			case 'H' :
			case 'h' :
			case 'm' :
			case 's' :
			case 'S' :
			case 'D' :
			case 'G' :
			case 'w' :
			case 'W' :
			case 'F' :
			case 'E' :
			case 'k' :
			case 'K' :
			case 'z' :
			case 'Z' :
				throw new IllegalArgumentException("Invalid date pattern : " + c);
		}
	}
}