java.lang.Object
java.util.AbstractMap
freemarker.template.utility.Collections12.EmptyMap
- All Implemented Interfaces:
- java.util.Map, java.io.Serializable
- Enclosing class:
- Collections12
- private static final class Collections12.EmptyMap
- extends java.util.AbstractMap
- implements java.io.Serializable
| Nested classes inherited from class java.util.AbstractMap |
|
| Nested classes inherited from class java.util.Map |
java.util.Map.Entry |
Collections12.EmptyMap
private Collections12.EmptyMap()
size
public int size()
- Description copied from class:
java.util.AbstractMap
- Returns the number of key-value mappings in the map. If there are more
than Integer.MAX_VALUE mappings, return Integer.MAX_VALUE. This is
implemented as
entrySet().size().
- Specified by:
size in interface java.util.Map
isEmpty
public boolean isEmpty()
- Description copied from class:
java.util.AbstractMap
- Returns true if the map contains no mappings. This is implemented by
size() == 0.
- Specified by:
isEmpty in interface java.util.Map
containsKey
public boolean containsKey(java.lang.Object key)
- Description copied from class:
java.util.AbstractMap
- Returns true if this contains a mapping for the given key. This
implementation does a linear search, O(n), over the
entrySet(), returning true if a match
is found, false if the iteration ends. Many subclasses
can implement this more efficiently.
- Specified by:
containsKey in interface java.util.Map
containsValue
public boolean containsValue(java.lang.Object value)
- Description copied from class:
java.util.AbstractMap
- Returns true if this contains at least one mapping with the given value.
This implementation does a linear search, O(n), over the
entrySet(), returning true if a match
is found, false if the iteration ends. A match is
defined as a value, v, where (value == null ? v == null :
value.equals(v)). Subclasses are unlikely to implement
this more efficiently.
- Specified by:
containsValue in interface java.util.Map
get
public java.lang.Object get(java.lang.Object key)
- Description copied from class:
java.util.AbstractMap
- Returns the value mapped by the given key. Returns
null if
there is no mapping. However, in Maps that accept null values, you
must rely on containsKey to determine if a mapping exists.
This iteration takes linear time, searching entrySet().iterator() of
the key. Many implementations override this method.
- Specified by:
get in interface java.util.Map
keySet
public java.util.Set keySet()
- Description copied from class:
java.util.AbstractMap
- Returns a set view of this map's keys. The set is backed by the map,
so changes in one show up in the other. Modifications while an iteration
is in progress produce undefined behavior. The set supports removal
if entrySet() does, but does not support element addition.
This implementation creates an AbstractSet, where the iterator wraps
the entrySet iterator, size defers to the Map's size, and contains
defers to the Map's containsKey. The set is created on first use, and
returned on subsequent uses, although since no synchronization occurs,
there is a slight possibility of creating two sets.
- Specified by:
keySet in interface java.util.Map
values
public java.util.Collection values()
- Description copied from class:
java.util.AbstractMap
- Returns a collection or bag view of this map's values. The collection
is backed by the map, so changes in one show up in the other.
Modifications while an iteration is in progress produce undefined
behavior. The collection supports removal if entrySet() does, but
does not support element addition.
This implementation creates an AbstractCollection, where the iterator
wraps the entrySet iterator, size defers to the Map's size, and contains
defers to the Map's containsValue. The collection is created on first
use, and returned on subsequent uses, although since no synchronization
occurs, there is a slight possibility of creating two collections.
- Specified by:
values in interface java.util.Map
entrySet
public java.util.Set entrySet()
- Description copied from class:
java.util.AbstractMap
- Returns a set view of the mappings in this Map. Each element in the
set must be an implementation of Map.Entry. The set is backed by
the map, so that changes in one show up in the other. Modifications
made while an iterator is in progress cause undefined behavior. If
the set supports removal, these methods must be valid:
Iterator.remove, Set.remove,
removeAll, retainAll, and clear.
Element addition is not supported via this set.
- Specified by:
entrySet in interface java.util.Map
equals
public boolean equals(java.lang.Object o)
- Description copied from class:
java.util.AbstractMap
- Compares the specified object with this map for equality. Returns
true if the other object is a Map with the same mappings,
that is,
o instanceof Map && entrySet().equals(((Map) o).entrySet();
- Specified by:
equals in interface java.util.Map
hashCode
public int hashCode()
- Description copied from class:
java.util.AbstractMap
- Returns the hash code for this map. As defined in Map, this is the sum
of all hashcodes for each Map.Entry object in entrySet, or basically
entrySet().hashCode().
- Specified by:
hashCode in interface java.util.Map
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