/*
* Copyright (c) 2002-2009 JGoodies Karsten Lentzsch. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* o Neither the name of JGoodies Karsten Lentzsch nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.jgoodies.forms.util;
import javax.swing.LookAndFeel;
import javax.swing.UIManager;
/**
* A library-internal class that consists only of static utility methods.
*
* <strong>Note: This class is not part of the public Forms API.
* It's intended for library implementation purposes only.
* The class's API may change at any time.</strong>
*
* @author Karsten Lentzsch
* @version $Revision: 1.11 $
*
* @since 1.2
*/
public final class FormUtils {
// Instance *************************************************************
private FormUtils() {
// Suppresses default constructor, prevents instantiation.
}
// API ********************************************************************
/**
* Throws an exception if the specified text is blank using the given
* text description.
*
* @param text the text to check
* @param description describes the text, used in the exception message
*
* @throws NullPointerException if {@code text} is {@code null}
* @throws IllegalArgumentException if {@code text} is empty, or blank
*/
public static void assertNotBlank(String text, String description) {
if (text == null) {
throw new NullPointerException("The " + description + " must not be null.");
}
if (FormUtils.isBlank(text)) {
throw new IllegalArgumentException(
"The " + description + " must not be empty, or whitespace. " +
"See FormUtils.isBlank(String)");
}
}
/**
* Throws an NPE if the given object is {@code null} that uses
* the specified text to describe the object.
*
* @param object the text to check
* @param description describes the object, used in the exception message
*
* @throws NullPointerException if {@code object} is {@code null}
*/
public static void assertNotNull(Object object, String description) {
if (object == null) {
throw new NullPointerException("The " + description + " must not be null.");
}
}
/**
* Checks and answers if the two objects are
* both {@code null} or equal.
*
* <pre>
* #equals(null, null) == true
* #equals("Hi", "Hi") == true
* #equals("Hi", null) == false
* #equals(null, "Hi") == false
* #equals("Hi", "Ho") == false
* </pre>
*
* @param o1 the first object to compare
* @param o2 the second object to compare
* @return boolean {@code true} if and only if
* both objects are {@code null} or equal
*/
public static boolean equals(Object o1, Object o2) {
return o1 != null && o2 != null && o1.equals(o2)
|| o1 == null && o2 == null;
}
/**
* Checks and answers if the given string is whitespace, empty (""),
* or {@code null}.
*
* <pre>
* FormUtils.isBlank(null) == true
* FormUtils.isBlank("") == true
* FormUtils.isBlank(" ") == true
* FormUtils.isBlank(" abc") == false
* FormUtils.isBlank("abc ") == false
* FormUtils.isBlank(" abc ") == false
* </pre>
*
* @param str the string to check, may be{@code null}
* @return {@code true} if the string is whitespace, empty, or {@code null}
*/
public static boolean isBlank(String str) {
int length;
if (str == null || (length = str.length()) == 0) {
return true;
}
for (int i = length - 1; i >= 0; i--) {
if (!Character.isWhitespace(str.charAt(i))) {
return false;
}
}
return true;
}
/**
* Checks and answers if the given string is not empty (""),
* not {@code null} and not whitespace only.
*
* <pre>
* FormUtils.isNotBlank(null) == false
* FormUtils.isNotBlank("") == false
* FormUtils.isNotBlank(" ") == false
* FormUtils.isNotBlank(" abc") == true
* FormUtils.isNotBlank("abc ") == true
* FormUtils.isNotBlank(" abc ") == true
* </pre>
*
* @param str the string to check, may be {@code null}
* @return {@code true} if the string is not empty
* and not {@code null} and not whitespace only
*/
public static boolean isNotBlank(String str) {
int length;
if (str == null || (length = str.length()) == 0) {
return false;
}
for (int i = length-1; i >= 0; i--) {
if (!Character.isWhitespace(str.charAt(i))) {
return true;
}
}
return false;
}
/**
* Lazily checks and answers whether the Aqua look&feel is active.
*
* @return {@code true} if the current look&feel is Aqua
*/
public static boolean isLafAqua() {
ensureValidCache();
if (cachedIsLafAqua == null) {
cachedIsLafAqua = Boolean.valueOf(computeIsLafAqua());
}
return cachedIsLafAqua.booleanValue();
}
// Caching and Lazily Computing the Laf State *****************************
/**
* Clears cached internal Forms state that is based
* on the Look&Feel, for example dialog base units.<p>
*
* There's typically no need to call this method directly.
* It'll be invoked automatically, if the L&F has been changed
* via {@link UIManager#setLookAndFeel} and cached data is requested.
* It's been made public to allow cache invalidation for cases
* where the L&F is changed temporarily by replacing the UIDefaults,
* for example in a visual editor.
*
* @since 1.2.1
*/
public static void clearLookAndFeelBasedCaches() {
cachedIsLafAqua = null;
DefaultUnitConverter.getInstance().clearCache();
}
/**
* Holds the LookAndFeel that has been used to computed cached values.
* If the current L&F differs from this cached value,
* the caches must be cleared.
*/
private static LookAndFeel cachedLookAndFeel;
/**
* Holds the cached result of the Aqua l&f check.
* Is invalidated if a look&feel change has been detected
* in <code>#ensureValidCache</code>.
*/
private static Boolean cachedIsLafAqua;
/**
* Computes and answers whether an Aqua look&feel is active.
* This may be Apple's Aqua L&f, or a sub-L&f that
* uses the same ID, because it doesn't substantially change the look.
*
* @return true if the current look&feel is Aqua
*/
private static boolean computeIsLafAqua() {
return UIManager.getLookAndFeel().getID().equals("Aqua");
}
static void ensureValidCache() {
LookAndFeel currentLookAndFeel = UIManager.getLookAndFeel();
if (currentLookAndFeel != cachedLookAndFeel) {
clearLookAndFeelBasedCaches();
cachedLookAndFeel = currentLookAndFeel;
}
}
}