Java tutorial
package org.jsoup.helper; /** * Simple validation methods. Designed for jsoup internal use */ public final class Validate { private Validate() { } /** * Validates that the object is not null * @param obj object to test */ public static void notNull(Object obj) { if (obj == null) throw new IllegalArgumentException("Object must not be null"); } /** * Validates that the object is not null * @param obj object to test * @param msg message to output if validation fails */ public static void notNull(Object obj, String msg) { if (obj == null) throw new IllegalArgumentException(msg); } /** * Validates that the value is true * @param val object to test */ public static void isTrue(boolean val) { if (!val) throw new IllegalArgumentException("Must be true"); } /** * Validates that the value is true * @param val object to test * @param msg message to output if validation fails */ public static void isTrue(boolean val, String msg) { if (!val) throw new IllegalArgumentException(msg); } /** * Validates that the value is false * @param val object to test */ public static void isFalse(boolean val) { if (val) throw new IllegalArgumentException("Must be false"); } /** * Validates that the value is false * @param val object to test * @param msg message to output if validation fails */ public static void isFalse(boolean val, String msg) { if (val) throw new IllegalArgumentException(msg); } /** * Validates that the array contains no null elements * @param objects the array to test */ public static void noNullElements(Object[] objects) { noNullElements(objects, "Array must not contain any null objects"); } /** * Validates that the array contains no null elements * @param objects the array to test * @param msg message to output if validation fails */ public static void noNullElements(Object[] objects, String msg) { for (Object obj : objects) if (obj == null) throw new IllegalArgumentException(msg); } /** * Validates that the string is not empty * @param string the string to test */ public static void notEmpty(String string) { if (string == null || string.length() == 0) throw new IllegalArgumentException("String must not be empty"); } /** * Validates that the string is not empty * @param string the string to test * @param msg message to output if validation fails */ public static void notEmpty(String string, String msg) { if (string == null || string.length() == 0) throw new IllegalArgumentException(msg); } /** Cause a failure. @param msg message to output. */ public static void fail(String msg) { throw new IllegalArgumentException(msg); } }