Java tutorial
package org.apache.http.util; import java.util.Collection; public class Args { public static void check(boolean z, String str) { if (!z) { throw new IllegalArgumentException(str); } } public static void check(boolean z, String str, Object... objArr) { if (!z) { throw new IllegalArgumentException(String.format(str, objArr)); } } public static <T> T notNull(T t, String str) { if (t != null) { return t; } throw new IllegalArgumentException(str + " may not be null"); } public static <T extends CharSequence> T notEmpty(T t, String str) { if (t == null) { throw new IllegalArgumentException(str + " may not be null"); } else if (!TextUtils.isEmpty(t)) { return t; } else { throw new IllegalArgumentException(str + " may not be empty"); } } public static <T extends CharSequence> T notBlank(T t, String str) { if (t == null) { throw new IllegalArgumentException(str + " may not be null"); } else if (!TextUtils.isBlank(t)) { return t; } else { throw new IllegalArgumentException(str + " may not be blank"); } } public static <E, T extends Collection<E>> T notEmpty(T t, String str) { if (t == null) { throw new IllegalArgumentException(str + " may not be null"); } else if (!t.isEmpty()) { return t; } else { throw new IllegalArgumentException(str + " may not be empty"); } } public static int positive(int i, String str) { if (i > 0) { return i; } throw new IllegalArgumentException(str + " may not be negative or zero"); } public static long positive(long j, String str) { if (j > 0) { return j; } throw new IllegalArgumentException(str + " may not be negative or zero"); } public static int notNegative(int i, String str) { if (i >= 0) { return i; } throw new IllegalArgumentException(str + " may not be negative"); } public static long notNegative(long j, String str) { if (j >= 0) { return j; } throw new IllegalArgumentException(str + " may not be negative"); } }