com.groupbyinc.common.apache.commons.collections4.EnumerationUtils 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.commons.collections4;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.StringTokenizer;
import org.apache.commons.collections4.iterators.EnumerationIterator;
/**
* Provides utility methods for {@link Enumeration} instances.
*
* @since 3.0
* @version $Id: EnumerationUtils.java 1683009 2015-06-01 21:53:01Z tn $
*/
public class EnumerationUtils {
/**
* EnumerationUtils is not normally instantiated.
*/
private EnumerationUtils() {}
/**
* Returns the index-th value in the {@link Enumeration}, throwing
* IndexOutOfBoundsException if there is no such element.
*
* The Enumeration is advanced to index (or to the end, if
* index exceeds the number of entries) as a side effect of this method.
*
* @param e the enumeration to get a value from
* @param index the index to get
* @param the type of object in the {@link Enumeration}
* @return the object at the specified index
* @throws IndexOutOfBoundsException if the index is invalid
* @throws IllegalArgumentException if the object type is invalid
* @since 4.1
*/
public static T get(final Enumeration e, final int index) {
int i = index;
CollectionUtils.checkIndexBounds(i);
while (e.hasMoreElements()) {
i--;
if (i == -1) {
return e.nextElement();
} else {
e.nextElement();
}
}
throw new IndexOutOfBoundsException("Entry does not exist: " + i);
}
/**
* Creates a list based on an enumeration.
*
* As the enumeration is traversed, an ArrayList of its values is
* created. The new list is returned.
*
* @param the element type
* @param enumeration the enumeration to traverse, which should not be null.
* @return a list containing all elements of the given enumeration
* @throws NullPointerException if the enumeration parameter is null.
*/
public static List toList(final Enumeration enumeration) {
return IteratorUtils.toList(new EnumerationIterator(enumeration));
}
/**
* Override toList(Enumeration) for StringTokenizer as it implements Enumeration<Object>
* for the sake of backward compatibility.
*
* @param stringTokenizer the tokenizer to convert to a {@link List}<{@link String}>
* @return a list containing all tokens of the given StringTokenizer
*/
public static List toList(final StringTokenizer stringTokenizer) {
final List result = new ArrayList(stringTokenizer.countTokens());
while (stringTokenizer.hasMoreTokens()) {
result.add(stringTokenizer.nextToken());
}
return result;
}
}