| /** |
| * 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.camel.util; |
| |
| import java.lang.reflect.Array; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.w3c.dom.NodeList; |
| |
| /** |
| * A number of helper methods for working with collections |
| * |
| * @version |
| */ |
| public final class CollectionHelper { |
| |
| /** |
| * Utility classes should not have a public constructor. |
| */ |
| private CollectionHelper() { |
| } |
| |
| /** |
| * Returns the size of the collection if it can be determined to be a collection |
| * |
| * @param value the collection |
| * @return the size, or <tt>null</tt> if not a collection |
| */ |
| public static Integer size(Object value) { |
| if (value != null) { |
| if (value instanceof Collection) { |
| Collection<?> collection = (Collection<?>)value; |
| return collection.size(); |
| } else if (value instanceof Map) { |
| Map<?, ?> map = (Map<?, ?>)value; |
| return map.size(); |
| } else if (value instanceof Object[]) { |
| Object[] array = (Object[])value; |
| return array.length; |
| } else if (value.getClass().isArray()) { |
| return Array.getLength(value); |
| } else if (value instanceof NodeList) { |
| NodeList nodeList = (NodeList)value; |
| return nodeList.getLength(); |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Sets the value of the entry in the map for the given key, though if the |
| * map already contains a value for the given key then the value is appended |
| * to a list of values. |
| * |
| * @param map the map to add the entry to |
| * @param key the key in the map |
| * @param value the value to put in the map |
| */ |
| @SuppressWarnings("unchecked") |
| public static void appendValue(Map map, Object key, Object value) { |
| Object oldValue = map.get(key); |
| if (oldValue != null) { |
| List list; |
| if (oldValue instanceof List) { |
| list = (List)oldValue; |
| } else { |
| list = new ArrayList(); |
| list.add(oldValue); |
| // replace old entry with list |
| map.remove(key); |
| map.put(key, list); |
| } |
| list.add(value); |
| } else { |
| map.put(key, value); |
| } |
| } |
| |
| public static <T> Set<T> createSetContaining(T... contents) { |
| Set<T> contentsAsSet = new HashSet<T>(); |
| contentsAsSet.addAll(Arrays.asList(contents)); |
| return contentsAsSet; |
| } |
| |
| public static String collectionAsCommaDelimitedString(String[] col) { |
| if (col == null || col.length == 0) { |
| return ""; |
| } |
| return collectionAsCommaDelimitedString(Arrays.asList(col)); |
| } |
| |
| public static String collectionAsCommaDelimitedString(Collection<?> col) { |
| if (col == null || col.isEmpty()) { |
| return ""; |
| } |
| |
| StringBuilder sb = new StringBuilder(); |
| Iterator<?> it = col.iterator(); |
| while (it.hasNext()) { |
| sb.append(it.next().toString()); |
| if (it.hasNext()) { |
| sb.append(","); |
| } |
| } |
| |
| return sb.toString(); |
| } |
| } |