org.apache.hadoop.lib.util.Check Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.lib.util;
import org.apache.hadoop.classification.InterfaceAudience;
import java.text.MessageFormat;
import java.util.List;
import java.util.regex.Pattern;
/**
* Utility methods to check preconditions.
*
* Commonly used for method arguments preconditions.
*/
@InterfaceAudience.Private
public class Check {
/**
* Verifies a variable is not NULL.
*
* @param obj the variable to check.
* @param name the name to use in the exception message.
*
* @return the variable.
*
* @throws IllegalArgumentException if the variable is NULL.
*/
public static T notNull(T obj, String name) {
if (obj == null) {
throw new IllegalArgumentException(name + " cannot be null");
}
return obj;
}
/**
* Verifies a list does not have any NULL elements.
*
* @param list the list to check.
* @param name the name to use in the exception message.
*
* @return the list.
*
* @throws IllegalArgumentException if the list has NULL elements.
*/
public static List notNullElements(List list, String name) {
notNull(list, name);
for (int i = 0; i < list.size(); i++) {
notNull(list.get(i), MessageFormat.format("list [{0}] element [{1}]", name, i));
}
return list;
}
/**
* Verifies a string is not NULL and not emtpy
*
* @param str the variable to check.
* @param name the name to use in the exception message.
*
* @return the variable.
*
* @throws IllegalArgumentException if the variable is NULL or empty.
*/
public static String notEmpty(String str, String name) {
if (str == null) {
throw new IllegalArgumentException(name + " cannot be null");
}
if (str.length() == 0) {
throw new IllegalArgumentException(name + " cannot be empty");
}
return str;
}
/**
* Verifies a string list is not NULL and not emtpy
*
* @param list the list to check.
* @param name the name to use in the exception message.
*
* @return the variable.
*
* @throws IllegalArgumentException if the string list has NULL or empty
* elements.
*/
public static List notEmptyElements(List list, String name) {
notNull(list, name);
for (int i = 0; i < list.size(); i++) {
notEmpty(list.get(i), MessageFormat.format("list [{0}] element [{1}]", name, i));
}
return list;
}
private static final String IDENTIFIER_PATTERN_STR = "[a-zA-Z_][a-zA-Z0-9_\\-]*";
private static final Pattern IDENTIFIER_PATTERN = Pattern.compile("^" + IDENTIFIER_PATTERN_STR + "$");
/**
* Verifies a value is a valid identifier,
* [a-zA-Z_][a-zA-Z0-9_\-]*, up to a maximum length.
*
* @param value string to check if it is a valid identifier.
* @param maxLen maximun length.
* @param name the name to use in the exception message.
*
* @return the value.
*
* @throws IllegalArgumentException if the string is not a valid identifier.
*/
public static String validIdentifier(String value, int maxLen, String name) {
Check.notEmpty(value, name);
if (value.length() > maxLen) {
throw new IllegalArgumentException(
MessageFormat.format("[{0}] = [{1}] exceeds max len [{2}]", name, value, maxLen));
}
if (!IDENTIFIER_PATTERN.matcher(value).find()) {
throw new IllegalArgumentException(
MessageFormat.format("[{0}] = [{1}] must be \"{2}\"", name, value, IDENTIFIER_PATTERN_STR));
}
return value;
}
/**
* Verifies an integer is greater than zero.
*
* @param value integer value.
* @param name the name to use in the exception message.
*
* @return the value.
*
* @throws IllegalArgumentException if the integer is zero or less.
*/
public static int gt0(int value, String name) {
return (int) gt0((long) value, name);
}
/**
* Verifies an long is greater than zero.
*
* @param value long value.
* @param name the name to use in the exception message.
*
* @return the value.
*
* @throws IllegalArgumentException if the long is zero or less.
*/
public static long gt0(long value, String name) {
if (value <= 0) {
throw new IllegalArgumentException(
MessageFormat.format("parameter [{0}] = [{1}] must be greater than zero", name, value));
}
return value;
}
/**
* Verifies an integer is greater or equal to zero.
*
* @param value integer value.
* @param name the name to use in the exception message.
*
* @return the value.
*
* @throws IllegalArgumentException if the integer is greater or equal to zero.
*/
public static int ge0(int value, String name) {
return (int) ge0((long) value, name);
}
/**
* Verifies an long is greater or equal to zero.
*
* @param value integer value.
* @param name the name to use in the exception message.
*
* @return the value.
*
* @throws IllegalArgumentException if the long is greater or equal to zero.
*/
public static long ge0(long value, String name) {
if (value < 0) {
throw new IllegalArgumentException(MessageFormat.format(
"parameter [{0}] = [{1}] must be greater than or equals zero", name, value));
}
return value;
}
}