Package org.eclipse.jetty.util
Class LazyList
- java.lang.Object
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- org.eclipse.jetty.util.LazyList
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- All Implemented Interfaces:
Serializable
,Cloneable
@Deprecated(since="2021-05-27") public class LazyList extends Object implements Cloneable, Serializable
Deprecated.The Eclipse Jetty and Apache Felix Http Jetty packages are no longer supported.Lazy List creation.A List helper class that attempts to avoid unnecessary List creation. If a method needs to create a List to return, but it is expected that this will either be empty or frequently contain a single item, then using LazyList will avoid additional object creations by using
Collections.EMPTY_LIST
orCollections.singletonList(Object)
where possible.LazyList works by passing an opaque representation of the list in and out of all the LazyList methods. This opaque object is either null for an empty list, an Object for a list with a single entry or an
UsageArrayList
for a list of items.Object lazylist =null; while(loopCondition) { Object item = getItem(); if (item.isToBeAdded()) lazylist = LazyList.add(lazylist,item); } return LazyList.getList(lazylist);
An ArrayList of default size is used as the initial LazyList.- See Also:
List
, Serialized Form
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Method Summary
All Methods Static Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static Object
add(Object list, int index, Object item)
Deprecated.Add an item to a LazyListstatic Object
add(Object list, Object item)
Deprecated.Add an item to a LazyListstatic Object
addArray(Object list, Object[] array)
Deprecated.Add the contents of an array to a LazyListstatic Object
addCollection(Object list, Collection<?> collection)
Deprecated.Add the contents of a Collection to a LazyListstatic Object
clone(Object list)
Deprecated.static boolean
contains(Object list, Object item)
Deprecated.static Object
ensureSize(Object list, int initialSize)
Deprecated.Ensure the capacity of the underlying list.static <E> E
get(Object list, int i)
Deprecated.Get item from the liststatic <E> List<E>
getList(Object list)
Deprecated.Get the real List from a LazyList.static <E> List<E>
getList(Object list, boolean nullForEmpty)
Deprecated.Get the real List from a LazyList.static boolean
hasEntry(Object list)
Deprecated.Simple utility method to test if List has at least 1 entry.static boolean
isEmpty(Object list)
Deprecated.Simple utility method to test if List is emptystatic <E> Iterator<E>
iterator(Object list)
Deprecated.static <E> ListIterator<E>
listIterator(Object list)
Deprecated.static Object
remove(Object list, int i)
Deprecated.static Object
remove(Object list, Object o)
Deprecated.static int
size(Object list)
Deprecated.The size of a lazy Liststatic Object
toArray(Object list, Class<?> clazz)
Deprecated.Convert a lazylist to an arraystatic String
toString(Object list)
Deprecated.static String[]
toStringArray(Object list)
Deprecated.
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Method Detail
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add
public static Object add(Object list, Object item)
Deprecated.Add an item to a LazyList- Parameters:
list
- The list to add to or null if none yet created.item
- The item to add.- Returns:
- The lazylist created or added to.
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add
public static Object add(Object list, int index, Object item)
Deprecated.Add an item to a LazyList- Parameters:
list
- The list to add to or null if none yet created.index
- The index to add the item at.item
- The item to add.- Returns:
- The lazylist created or added to.
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addCollection
public static Object addCollection(Object list, Collection<?> collection)
Deprecated.Add the contents of a Collection to a LazyList- Parameters:
list
- The list to add to or null if none yet created.collection
- The Collection whose contents should be added.- Returns:
- The lazylist created or added to.
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addArray
public static Object addArray(Object list, Object[] array)
Deprecated.Add the contents of an array to a LazyList- Parameters:
list
- The list to add to or null if none yet created.array
- The array whose contents should be added.- Returns:
- The lazylist created or added to.
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ensureSize
public static Object ensureSize(Object list, int initialSize)
Deprecated.Ensure the capacity of the underlying list.- Parameters:
list
- the list to growinitialSize
- the size to grow to- Returns:
- the new List with new size
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getList
public static <E> List<E> getList(Object list)
Deprecated.Get the real List from a LazyList.- Type Parameters:
E
- the list entry type- Parameters:
list
- A LazyList returned from LazyList.add(Object)- Returns:
- The List of added items, which may be an EMPTY_LIST or a SingletonList.
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getList
public static <E> List<E> getList(Object list, boolean nullForEmpty)
Deprecated.Get the real List from a LazyList.- Type Parameters:
E
- the list entry type- Parameters:
list
- A LazyList returned from LazyList.add(Object) or nullnullForEmpty
- If true, null is returned instead of an empty list.- Returns:
- The List of added items, which may be null, an EMPTY_LIST or a SingletonList.
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hasEntry
public static boolean hasEntry(Object list)
Deprecated.Simple utility method to test if List has at least 1 entry.
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isEmpty
public static boolean isEmpty(Object list)
Deprecated.Simple utility method to test if List is empty
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toArray
public static Object toArray(Object list, Class<?> clazz)
Deprecated.Convert a lazylist to an array- Parameters:
list
- The list to convertclazz
- The class of the array, which may be a primitive type- Returns:
- array of the lazylist entries passed in
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size
public static int size(Object list)
Deprecated.The size of a lazy List- Parameters:
list
- A LazyList returned from LazyList.add(Object) or null- Returns:
- the size of the list.
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get
public static <E> E get(Object list, int i)
Deprecated.Get item from the list- Type Parameters:
E
- the list entry type- Parameters:
list
- A LazyList returned from LazyList.add(Object) or nulli
- int index- Returns:
- the item from the list.
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listIterator
public static <E> ListIterator<E> listIterator(Object list)
Deprecated.
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