package org.scribe.utils;
import java.util.regex.Pattern;
import org.scribe.model.OAuthConstants;
/**
* Utils for checking preconditions and invariants
*
* @author Pablo Fernandez
*/
public class Preconditions
{
private static final String DEFAULT_MESSAGE = "Received an invalid parameter";
private static final Pattern URL_PATTERN = Pattern.compile("[a-zA-Z_-]+://\\S+");
/**
* Checks that an object is not null.
*
* @param object any object
* @param errorMsg error message
*
* @throws IllegalArgumentException if the object is null
*/
public static void checkNotNull(Object object, String errorMsg)
{
check(object != null, errorMsg);
}
/**
* Checks that a string is not null or empty
*
* @param string any string
* @param errorMsg error message
*
* @throws IllegalArgumentException if the string is null or empty
*/
public static void checkEmptyString(String string, String errorMsg)
{
check(string != null && !string.trim().equals(""), errorMsg);
}
/**
* Checks that a URL is valid
*
* @param url any string
* @param errorMsg error message
*/
public static void checkValidUrl(String url, String errorMsg)
{
checkEmptyString(url, errorMsg);
check(isUrl(url), errorMsg);
}
/**
* Checks that a URL is a valid OAuth callback
*
* @param url any string
* @param errorMsg error message
*/
public static void checkValidOAuthCallback(String url, String errorMsg)
{
checkEmptyString(url, errorMsg);
if(url.toLowerCase().compareToIgnoreCase(OAuthConstants.OUT_OF_BAND) != 0)
{
check(isUrl(url), errorMsg);
}
}
private static boolean isUrl(String url)
{
return URL_PATTERN.matcher(url).matches();
}
private static void check(boolean requirements, String error)
{
String message = (error == null || error.trim().length() <= 0) ? DEFAULT_MESSAGE : error;
if (!requirements)
{
throw new IllegalArgumentException(message);
}
}
}