public static Collection createApproximateCollection(Object collection,
    int initialCapacity) 
{
		if (collection instanceof LinkedList) {
			return new LinkedList();
		}
		else if (collection instanceof List) {
			return new ArrayList(initialCapacity);
		}
		else if (collection instanceof SortedSet) {
			return new TreeSet(((SortedSet) collection).comparator());
		}
		else {
			return new LinkedHashSet(initialCapacity);
		}
}

Create the most approximate collection for the given collection.

Creates an ArrayList, TreeSet or linked Set for a List, SortedSet or Set, respectively.

 public static Map createApproximateMap(Object map,
    int initialCapacity) 
{
		if (map instanceof SortedMap) {
			return new TreeMap(((SortedMap) map).comparator());
		}
		else {
			return new LinkedHashMap(initialCapacity);
		}
}

Create the most approximate map for the given map.

Creates a TreeMap or linked Map for a SortedMap or Map, respectively.

 public static ConcurrentMap createConcurrentMap(int initialCapacity) 
{
		if (JdkVersion.isAtLeastJava15()) {
			logger.trace("Creating [java.util.concurrent.ConcurrentHashMap]");
			return new JdkConcurrentHashMap(initialCapacity);
		}
		else if (backportConcurrentAvailable) {
			logger.trace("Creating [edu.emory.mathcs.backport.java.util.concurrent.ConcurrentHashMap]");
			return new BackportConcurrentHashMap(initialCapacity);
		}
		else {
			throw new IllegalStateException("Cannot create ConcurrentHashMap - " +
					"neither JDK 1.5 nor backport-concurrent available on the classpath");
		}
}

Create a concurrent Map with a dedicated ConcurrentMap interface, requiring JDK >= 1.5 or the backport-concurrent library on the classpath. Prefers a JDK 1.5+ ConcurrentHashMap to its backport-concurrent equivalent. Throws an IllegalStateException if no concurrent Map is available.

 public static Map createConcurrentMapIfPossible(int initialCapacity) 
{
		if (JdkVersion.isAtLeastJava15()) {
			logger.trace("Creating [java.util.concurrent.ConcurrentHashMap]");
			return JdkConcurrentCollectionFactory.createConcurrentHashMap(initialCapacity);
		}
		else if (backportConcurrentAvailable) {
			logger.trace("Creating [edu.emory.mathcs.backport.java.util.concurrent.ConcurrentHashMap]");
			return BackportConcurrentCollectionFactory.createConcurrentHashMap(initialCapacity);
		}
		else {
			logger.debug("Falling back to plain synchronized [java.util.HashMap] for concurrent map");
			return Collections.synchronizedMap(new HashMap(initialCapacity));
		}
}

Create a concurrent Map if possible: that is, if running on JDK >= 1.5 or if the backport-concurrent library is available. Prefers a JDK 1.5+ ConcurrentHashMap to its backport-concurrent equivalent. Falls back to a plain synchronized HashMap if no concurrent Map is available.

 public static Set createCopyOnWriteSet() 
{
		if (JdkVersion.isAtLeastJava15()) {
			logger.trace("Creating [java.util.concurrent.CopyOnWriteArraySet]");
			return JdkConcurrentCollectionFactory.createCopyOnWriteArraySet();
		}
		else if (backportConcurrentAvailable) {
			logger.trace("Creating [edu.emory.mathcs.backport.java.util.concurrent.CopyOnWriteArraySet]");
			return BackportConcurrentCollectionFactory.createCopyOnWriteArraySet();
		}
		else {
			throw new IllegalStateException("Cannot create CopyOnWriteArraySet - " +
					"neither JDK 1.5 nor backport-concurrent available on the classpath");
		}
}

Create a copy-on-write Set (allowing for synchronization-less iteration), requiring JDK >= 1.5 or the backport-concurrent library on the classpath. Prefers a JDK 1.5+ CopyOnWriteArraySet to its backport-concurrent equivalent. Throws an IllegalStateException if no copy-on-write Set is available.

 public static Map createIdentityMapIfPossible(int initialCapacity) 
{
		return new IdentityHashMap(initialCapacity);
}

Create an identity Map if possible: This implementation always creates a java.util.IdentityHashMap , since Spring 2.5 requires JDK 1.4 anyway.

 public static Map createLinkedCaseInsensitiveMapIfPossible(int initialCapacity) 
{
		if (commonsCollections3Available) {
			logger.trace("Creating [org.apache.commons.collections.map.ListOrderedMap/CaseInsensitiveMap]");
			return CommonsCollectionFactory.createListOrderedCaseInsensitiveMap(initialCapacity);
		}
		else {
			logger.debug("Falling back to [java.util.LinkedHashMap] for linked case-insensitive map");
			return new LinkedHashMap(initialCapacity);
		}
}

Create a linked case-insensitive Map if possible: if Commons Collections 3.x is available, a CaseInsensitiveMap with ListOrderedMap decorator will be created. Else, a JDK java.util.LinkedHashMap will be used.

 public static Map createLinkedMapIfPossible(int initialCapacity) 
{
		return new LinkedHashMap(initialCapacity);
}

Create a linked Map if possible: This implementation always creates a java.util.LinkedHashMap , since Spring 2.5 requires JDK 1.4 anyway.

 public static Set createLinkedSetIfPossible(int initialCapacity) 
{
	 
		approximableCollectionTypes.add(Collection.class);
		approximableCollectionTypes.add(List.class);
		approximableCollectionTypes.add(Set.class);
		approximableCollectionTypes.add(SortedSet.class);
		approximableMapTypes.add(Map.class);
		approximableMapTypes.add(SortedMap.class);
		if (JdkVersion.isAtLeastJava16()) {
			approximableCollectionTypes.add(NavigableSet.class);
			approximableMapTypes.add(NavigableMap.class);
		}
		approximableCollectionTypes.add(ArrayList.class);
		approximableCollectionTypes.add(LinkedList.class);
		approximableCollectionTypes.add(HashSet.class);
		approximableCollectionTypes.add(LinkedHashSet.class);
		approximableCollectionTypes.add(TreeSet.class);
		approximableMapTypes.add(HashMap.class);
		approximableMapTypes.add(LinkedHashMap.class);
		approximableMapTypes.add(TreeMap.class);
		return new LinkedHashSet(initialCapacity);
}

Create a linked Set if possible: This implementation always creates a java.util.LinkedHashSet , since Spring 2.5 requires JDK 1.4 anyway.

 public static boolean isApproximableCollectionType(Class collectionType) 
{
		return (collectionType != null && approximableCollectionTypes.contains(collectionType));
}

Determine whether the given collection type is an approximable type, i.e. a type that #createApproximateCollection can approximate.

 public static boolean isApproximableMapType(Class mapType) 
{
		return (mapType != null && approximableMapTypes.contains(mapType));
}

Determine whether the given map type is an approximable type, i.e. a type that #createApproximateMap can approximate.