BagUtils ("The Adobe AEM Quickstart and Web Application.")

java.lang.Object
- org.apache.commons.collections4.BagUtils

```
public class BagUtils
extends java.lang.Object
```
Provides utility methods and decorators for Bag and SortedBag instances.

Since:

2.1

Field Summary

Fields
Modifier and Type Field and Description

static Bag EMPTY_BAG
An empty unmodifiable bag.

static Bag EMPTY_SORTED_BAG
An empty unmodifiable sorted bag.

Fields
Modifier and Type	Field and Description
`static Bag`	`EMPTY_BAG` An empty unmodifiable bag.
`static Bag`	`EMPTY_SORTED_BAG` An empty unmodifiable sorted bag.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <E> Bag<E>`	`collectionBag(Bag<E> bag)` Returns a bag that complies to the Collection contract, backed by the given bag.
`static <E> Bag<E>`	`emptyBag()` Get an empty `Bag`.
`static <E> SortedBag<E>`	`emptySortedBag()` Get an empty `SortedBag`.
`static <E> Bag<E>`	`predicatedBag(Bag<E> bag, Predicate<? super E> predicate)` Returns a predicated (validating) bag backed by the given bag.
`static <E> SortedBag<E>`	`predicatedSortedBag(SortedBag<E> bag, Predicate<? super E> predicate)` Returns a predicated (validating) sorted bag backed by the given sorted bag.
`static <E> Bag<E>`	`synchronizedBag(Bag<E> bag)` Returns a synchronized (thread-safe) bag backed by the given bag.
`static <E> SortedBag<E>`	`synchronizedSortedBag(SortedBag<E> bag)` Returns a synchronized (thread-safe) sorted bag backed by the given sorted bag.
`static <E> Bag<E>`	`transformingBag(Bag<E> bag, Transformer<? super E,? extends E> transformer)` Returns a transformed bag backed by the given bag.
`static <E> SortedBag<E>`	`transformingSortedBag(SortedBag<E> bag, Transformer<? super E,? extends E> transformer)` Returns a transformed sorted bag backed by the given bag.
`static <E> Bag<E>`	`unmodifiableBag(Bag<? extends E> bag)` Returns an unmodifiable view of the given bag.
`static <E> SortedBag<E>`	`unmodifiableSortedBag(SortedBag<E> bag)` Returns an unmodifiable view of the given sorted bag.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - EMPTY_BAG
```
public static final Bag EMPTY_BAG
```
    An empty unmodifiable bag.
  - EMPTY_SORTED_BAG
```
public static final Bag EMPTY_SORTED_BAG
```
    An empty unmodifiable sorted bag.
- Method Detail
  - synchronizedBag
```
public static <E> Bag<E> synchronizedBag(Bag<E> bag)
```
    Returns a synchronized (thread-safe) bag backed by the given bag. In order to guarantee serial access, it is critical that all access to the backing bag is accomplished through the returned bag.
    It is imperative that the user manually synchronize on the returned bag when iterating over it:
```
 Bag bag = BagUtils.synchronizedBag(new HashBag());
 ...
 synchronized(bag) {
     Iterator i = bag.iterator(); // Must be in synchronized block
     while (i.hasNext())
         foo(i.next());
     }
 }
 
```
    Failure to follow this advice may result in non-deterministic behavior.
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to synchronize, must not be null
    
    Returns:
    
    a synchronized bag backed by that bag
    
    Throws:
    
    java.lang.NullPointerException - if the Bag is null
  - unmodifiableBag
```
public static <E> Bag<E> unmodifiableBag(Bag<? extends E> bag)
```
    Returns an unmodifiable view of the given bag. Any modification attempts to the returned bag will raise an UnsupportedOperationException.
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag whose unmodifiable view is to be returned, must not be null
    
    Returns:
    
    an unmodifiable view of that bag
    
    Throws:
    
    java.lang.NullPointerException - if the Bag is null
  - predicatedBag
```
public static <E> Bag<E> predicatedBag(Bag<E> bag,
                                       Predicate<? super E> predicate)
```
    Returns a predicated (validating) bag backed by the given bag.
    Only objects that pass the test in the given predicate can be added to the bag. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original bag after invoking this method, as it is a backdoor for adding invalid objects.
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to predicate, must not be null
    
    predicate - the predicate for the bag, must not be null
    
    Returns:
    
    a predicated bag backed by the given bag
    
    Throws:
    
    java.lang.NullPointerException - if the Bag or Predicate is null
  - transformingBag
```
public static <E> Bag<E> transformingBag(Bag<E> bag,
                                         Transformer<? super E,? extends E> transformer)
```
    Returns a transformed bag backed by the given bag.
    Each object is passed through the transformer as it is added to the Bag. It is important not to use the original bag after invoking this method, as it is a backdoor for adding untransformed objects.
    Existing entries in the specified bag will not be transformed. If you want that behaviour, see TransformedBag.transformedBag(Bag, Transformer).
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to predicate, must not be null
    
    transformer - the transformer for the bag, must not be null
    
    Returns:
    
    a transformed bag backed by the given bag
    
    Throws:
    
    java.lang.NullPointerException - if the Bag or Transformer is null
  - collectionBag
```
public static <E> Bag<E> collectionBag(Bag<E> bag)
```
    Returns a bag that complies to the Collection contract, backed by the given bag.
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to decorate, must not be null
    
    Returns:
    
    a Bag that complies to the Collection contract
    
    Throws:
    
    java.lang.NullPointerException - if bag is null
    
    Since:
    
    4.0
  - synchronizedSortedBag
```
public static <E> SortedBag<E> synchronizedSortedBag(SortedBag<E> bag)
```
    Returns a synchronized (thread-safe) sorted bag backed by the given sorted bag. In order to guarantee serial access, it is critical that all access to the backing bag is accomplished through the returned bag.
    It is imperative that the user manually synchronize on the returned bag when iterating over it:
```
 SortedBag bag = BagUtils.synchronizedSortedBag(new TreeBag());
 ...
 synchronized(bag) {
     Iterator i = bag.iterator(); // Must be in synchronized block
     while (i.hasNext())
         foo(i.next());
     }
 }
 
```
    Failure to follow this advice may result in non-deterministic behavior.
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to synchronize, must not be null
    
    Returns:
    
    a synchronized bag backed by that bag
    
    Throws:
    
    java.lang.NullPointerException - if the SortedBag is null
  - unmodifiableSortedBag
```
public static <E> SortedBag<E> unmodifiableSortedBag(SortedBag<E> bag)
```
    Returns an unmodifiable view of the given sorted bag. Any modification attempts to the returned bag will raise an UnsupportedOperationException.
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag whose unmodifiable view is to be returned, must not be null
    
    Returns:
    
    an unmodifiable view of that bag
    
    Throws:
    
    java.lang.NullPointerException - if the SortedBag is null
  - predicatedSortedBag
```
public static <E> SortedBag<E> predicatedSortedBag(SortedBag<E> bag,
                                                   Predicate<? super E> predicate)
```
    Returns a predicated (validating) sorted bag backed by the given sorted bag.
    Only objects that pass the test in the given predicate can be added to the bag. Trying to add an invalid object results in an IllegalArgumentException. It is important not to use the original bag after invoking this method, as it is a backdoor for adding invalid objects.
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the sorted bag to predicate, must not be null
    
    predicate - the predicate for the bag, must not be null
    
    Returns:
    
    a predicated bag backed by the given bag
    
    Throws:
    
    java.lang.NullPointerException - if the SortedBag or Predicate is null
  - transformingSortedBag
```
public static <E> SortedBag<E> transformingSortedBag(SortedBag<E> bag,
                                                     Transformer<? super E,? extends E> transformer)
```
    Returns a transformed sorted bag backed by the given bag.
    Each object is passed through the transformer as it is added to the Bag. It is important not to use the original bag after invoking this method, as it is a backdoor for adding untransformed objects.
    Existing entries in the specified bag will not be transformed. If you want that behaviour, see TransformedSortedBag.transformedSortedBag(SortedBag, Transformer).
    
    Type Parameters:
    
    E - the element type
    
    Parameters:
    
    bag - the bag to predicate, must not be null
    
    transformer - the transformer for the bag, must not be null
    
    Returns:
    
    a transformed bag backed by the given bag
    
    Throws:
    
    java.lang.NullPointerException - if the Bag or Transformer is null
  - emptyBag
```
public static <E> Bag<E> emptyBag()
```
    Get an empty Bag.
    
    Type Parameters:
    
    E - the element type
    
    Returns:
    
    an empty Bag
  - emptySortedBag
```
public static <E> SortedBag<E> emptySortedBag()
```
    Get an empty SortedBag.
    
    Type Parameters:
    
    E - the element type
    
    Returns:
    
    an empty sorted Bag

Class BagUtils

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EMPTY_BAG

EMPTY_SORTED_BAG

Method Detail

synchronizedBag

unmodifiableBag

predicatedBag

transformingBag

collectionBag

synchronizedSortedBag

unmodifiableSortedBag

predicatedSortedBag

transformingSortedBag

emptyBag

emptySortedBag