public class MapUtils
extends java.lang.Object
Map
and SortedMap
instances.
It contains various type safe methods as well as other useful features like deep copying.
It also provides the following decorators:
fixedSizeMap(Map)
fixedSizeSortedMap(SortedMap)
lazyMap(Map,Factory)
lazyMap(Map,Transformer)
lazySortedMap(SortedMap,Factory)
lazySortedMap(SortedMap,Transformer)
predicatedMap(Map,Predicate,Predicate)
predicatedSortedMap(SortedMap,Predicate,Predicate)
transformedMap(Map, Transformer, Transformer)
transformedSortedMap(SortedMap, Transformer, Transformer)
typedMap(Map, Class, Class)
typedSortedMap(SortedMap, Class, Class)
multiValueMap( Map )
multiValueMap( Map, Class )
multiValueMap( Map, Factory )
Modifier and Type | Field and Description |
---|---|
static java.util.Map |
EMPTY_MAP
An empty unmodifiable map.
|
static java.util.SortedMap |
EMPTY_SORTED_MAP
An empty unmodifiable sorted map.
|
Constructor and Description |
---|
MapUtils()
MapUtils should not normally be instantiated. |
Modifier and Type | Method and Description |
---|---|
static void |
debugPrint(java.io.PrintStream out,
java.lang.Object label,
java.util.Map map)
Prints the given map with nice line breaks.
|
static java.util.Map |
fixedSizeMap(java.util.Map map)
Returns a fixed-sized map backed by the given map.
|
static java.util.SortedMap |
fixedSizeSortedMap(java.util.SortedMap map)
Returns a fixed-sized sorted map backed by the given sorted map.
|
static java.lang.Boolean |
getBoolean(java.util.Map map,
java.lang.Object key)
Gets a Boolean from a Map in a null-safe manner.
|
static java.lang.Boolean |
getBoolean(java.util.Map map,
java.lang.Object key,
java.lang.Boolean defaultValue)
Looks up the given key in the given map, converting the result into
a boolean, using the default value if the the conversion fails.
|
static boolean |
getBooleanValue(java.util.Map map,
java.lang.Object key)
Gets a boolean from a Map in a null-safe manner.
|
static boolean |
getBooleanValue(java.util.Map map,
java.lang.Object key,
boolean defaultValue)
Gets a boolean from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.Byte |
getByte(java.util.Map map,
java.lang.Object key)
Gets a Byte from a Map in a null-safe manner.
|
static java.lang.Byte |
getByte(java.util.Map map,
java.lang.Object key,
java.lang.Byte defaultValue)
Looks up the given key in the given map, converting the result into
a byte, using the default value if the the conversion fails.
|
static byte |
getByteValue(java.util.Map map,
java.lang.Object key)
Gets a byte from a Map in a null-safe manner.
|
static byte |
getByteValue(java.util.Map map,
java.lang.Object key,
byte defaultValue)
Gets a byte from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.Double |
getDouble(java.util.Map map,
java.lang.Object key)
Gets a Double from a Map in a null-safe manner.
|
static java.lang.Double |
getDouble(java.util.Map map,
java.lang.Object key,
java.lang.Double defaultValue)
Looks up the given key in the given map, converting the result into
a double, using the default value if the the conversion fails.
|
static double |
getDoubleValue(java.util.Map map,
java.lang.Object key)
Gets a double from a Map in a null-safe manner.
|
static double |
getDoubleValue(java.util.Map map,
java.lang.Object key,
double defaultValue)
Gets a double from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.Float |
getFloat(java.util.Map map,
java.lang.Object key)
Gets a Float from a Map in a null-safe manner.
|
static java.lang.Float |
getFloat(java.util.Map map,
java.lang.Object key,
java.lang.Float defaultValue)
Looks up the given key in the given map, converting the result into
a float, using the default value if the the conversion fails.
|
static float |
getFloatValue(java.util.Map map,
java.lang.Object key)
Gets a float from a Map in a null-safe manner.
|
static float |
getFloatValue(java.util.Map map,
java.lang.Object key,
float defaultValue)
Gets a float from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.Integer |
getInteger(java.util.Map map,
java.lang.Object key)
Gets a Integer from a Map in a null-safe manner.
|
static java.lang.Integer |
getInteger(java.util.Map map,
java.lang.Object key,
java.lang.Integer defaultValue)
Looks up the given key in the given map, converting the result into
an integer, using the default value if the the conversion fails.
|
static int |
getIntValue(java.util.Map map,
java.lang.Object key)
Gets an int from a Map in a null-safe manner.
|
static int |
getIntValue(java.util.Map map,
java.lang.Object key,
int defaultValue)
Gets an int from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.Long |
getLong(java.util.Map map,
java.lang.Object key)
Gets a Long from a Map in a null-safe manner.
|
static java.lang.Long |
getLong(java.util.Map map,
java.lang.Object key,
java.lang.Long defaultValue)
Looks up the given key in the given map, converting the result into
a long, using the default value if the the conversion fails.
|
static long |
getLongValue(java.util.Map map,
java.lang.Object key)
Gets a long from a Map in a null-safe manner.
|
static long |
getLongValue(java.util.Map map,
java.lang.Object key,
long defaultValue)
Gets a long from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.util.Map |
getMap(java.util.Map map,
java.lang.Object key)
Gets a Map from a Map in a null-safe manner.
|
static java.util.Map |
getMap(java.util.Map map,
java.lang.Object key,
java.util.Map defaultValue)
Looks up the given key in the given map, converting the result into
a map, using the default value if the the conversion fails.
|
static java.lang.Number |
getNumber(java.util.Map map,
java.lang.Object key)
Gets a Number from a Map in a null-safe manner.
|
static java.lang.Number |
getNumber(java.util.Map map,
java.lang.Object key,
java.lang.Number defaultValue)
Looks up the given key in the given map, converting the result into
a number, using the default value if the the conversion fails.
|
static java.lang.Object |
getObject(java.util.Map map,
java.lang.Object key)
Gets from a Map in a null-safe manner.
|
static java.lang.Object |
getObject(java.util.Map map,
java.lang.Object key,
java.lang.Object defaultValue)
Looks up the given key in the given map, converting null into the
given default value.
|
static java.lang.Short |
getShort(java.util.Map map,
java.lang.Object key)
Gets a Short from a Map in a null-safe manner.
|
static java.lang.Short |
getShort(java.util.Map map,
java.lang.Object key,
java.lang.Short defaultValue)
Looks up the given key in the given map, converting the result into
a short, using the default value if the the conversion fails.
|
static short |
getShortValue(java.util.Map map,
java.lang.Object key)
Gets a short from a Map in a null-safe manner.
|
static short |
getShortValue(java.util.Map map,
java.lang.Object key,
short defaultValue)
Gets a short from a Map in a null-safe manner,
using the default value if the the conversion fails.
|
static java.lang.String |
getString(java.util.Map map,
java.lang.Object key)
Gets a String from a Map in a null-safe manner.
|
static java.lang.String |
getString(java.util.Map map,
java.lang.Object key,
java.lang.String defaultValue)
Looks up the given key in the given map, converting the result into
a string, using the default value if the the conversion fails.
|
static java.util.Map |
invertMap(java.util.Map map)
Inverts the supplied map returning a new HashMap such that the keys of
the input are swapped with the values.
|
static boolean |
isEmpty(java.util.Map map)
Null-safe check if the specified map is empty.
|
static boolean |
isNotEmpty(java.util.Map map)
Null-safe check if the specified map is not empty.
|
static java.util.Map |
lazyMap(java.util.Map map,
Factory factory)
Returns a "lazy" map whose values will be created on demand.
|
static java.util.Map |
lazyMap(java.util.Map map,
Transformer transformerFactory)
Returns a "lazy" map whose values will be created on demand.
|
static java.util.SortedMap |
lazySortedMap(java.util.SortedMap map,
Factory factory)
Returns a "lazy" sorted map whose values will be created on demand.
|
static java.util.SortedMap |
lazySortedMap(java.util.SortedMap map,
Transformer transformerFactory)
Returns a "lazy" sorted map whose values will be created on demand.
|
static java.util.Map |
multiValueMap(java.util.Map map)
Creates a mult-value map backed by the given map which returns
collections of type ArrayList.
|
static java.util.Map |
multiValueMap(java.util.Map map,
java.lang.Class collectionClass)
Creates a multi-value map backed by the given map which returns
collections of the specified type.
|
static java.util.Map |
multiValueMap(java.util.Map map,
Factory collectionFactory)
Creates a multi-value map backed by the given map which returns
collections created by the specified collection factory.
|
static java.util.Map |
orderedMap(java.util.Map map)
Returns a map that maintains the order of keys that are added
backed by the given map.
|
static java.util.Map |
predicatedMap(java.util.Map map,
Predicate keyPred,
Predicate valuePred)
Returns a predicated (validating) map backed by the given map.
|
static java.util.SortedMap |
predicatedSortedMap(java.util.SortedMap map,
Predicate keyPred,
Predicate valuePred)
Returns a predicated (validating) sorted map backed by the given map.
|
static java.util.Map |
putAll(java.util.Map map,
java.lang.Object[] array)
Puts all the keys and values from the specified array into the map.
|
static void |
safeAddToMap(java.util.Map map,
java.lang.Object key,
java.lang.Object value)
Protects against adding null values to a map.
|
static java.util.Map |
synchronizedMap(java.util.Map map)
Returns a synchronized map backed by the given map.
|
static java.util.Map |
synchronizedSortedMap(java.util.SortedMap map)
Returns a synchronized sorted map backed by the given sorted map.
|
static java.util.Map |
toMap(java.util.ResourceBundle resourceBundle)
Creates a new HashMap using data copied from a ResourceBundle.
|
static java.util.Properties |
toProperties(java.util.Map map)
Gets a new Properties object initialised with the values from a Map.
|
static java.util.Map |
transformedMap(java.util.Map map,
Transformer keyTransformer,
Transformer valueTransformer)
Returns a transformed map backed by the given map.
|
static java.util.SortedMap |
transformedSortedMap(java.util.SortedMap map,
Transformer keyTransformer,
Transformer valueTransformer)
Returns a transformed sorted map backed by the given map.
|
static java.util.Map |
typedMap(java.util.Map map,
java.lang.Class keyType,
java.lang.Class valueType)
Returns a typed map backed by the given map.
|
static java.util.SortedMap |
typedSortedMap(java.util.SortedMap map,
java.lang.Class keyType,
java.lang.Class valueType)
Returns a typed sorted map backed by the given map.
|
static java.util.Map |
unmodifiableMap(java.util.Map map)
Returns an unmodifiable map backed by the given map.
|
static java.util.Map |
unmodifiableSortedMap(java.util.SortedMap map)
Returns an unmodifiable sorted map backed by the given sorted map.
|
static void |
verbosePrint(java.io.PrintStream out,
java.lang.Object label,
java.util.Map map)
Prints the given map with nice line breaks.
|
public static final java.util.Map EMPTY_MAP
public static final java.util.SortedMap EMPTY_SORTED_MAP
public static java.lang.Object getObject(java.util.Map map, java.lang.Object key)
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.String getString(java.util.Map map, java.lang.Object key)
The String is obtained via toString
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Boolean getBoolean(java.util.Map map, java.lang.Object key)
If the value is a Boolean
it is returned directly.
If the value is a String
and it equals 'true' ignoring case
then true
is returned, otherwise false
.
If the value is a Number
an integer zero value returns
false
and non-zero returns true
.
Otherwise, null
is returned.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Number getNumber(java.util.Map map, java.lang.Object key)
If the value is a Number
it is returned directly.
If the value is a String
it is converted using
NumberFormat.parse(String)
on the system default formatter
returning null
if the conversion fails.
Otherwise, null
is returned.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Byte getByte(java.util.Map map, java.lang.Object key)
The Byte is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Short getShort(java.util.Map map, java.lang.Object key)
The Short is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Integer getInteger(java.util.Map map, java.lang.Object key)
The Integer is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Long getLong(java.util.Map map, java.lang.Object key)
The Long is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Float getFloat(java.util.Map map, java.lang.Object key)
The Float is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Double getDouble(java.util.Map map, java.lang.Object key)
The Double is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.util.Map getMap(java.util.Map map, java.lang.Object key)
If the value returned from the specified map is not a Map then
null
is returned.
map
- the map to usekey
- the key to look upnull
if null map inputpublic static java.lang.Object getObject(java.util.Map map, java.lang.Object key, java.lang.Object defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is nullpublic static java.lang.String getString(java.util.Map map, java.lang.Object key, java.lang.String defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Boolean getBoolean(java.util.Map map, java.lang.Object key, java.lang.Boolean defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Number getNumber(java.util.Map map, java.lang.Object key, java.lang.Number defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Byte getByte(java.util.Map map, java.lang.Object key, java.lang.Byte defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Short getShort(java.util.Map map, java.lang.Object key, java.lang.Short defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Integer getInteger(java.util.Map map, java.lang.Object key, java.lang.Integer defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Long getLong(java.util.Map map, java.lang.Object key, java.lang.Long defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Float getFloat(java.util.Map map, java.lang.Object key, java.lang.Float defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.lang.Double getDouble(java.util.Map map, java.lang.Object key, java.lang.Double defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static java.util.Map getMap(java.util.Map map, java.lang.Object key, java.util.Map defaultValue)
map
- the map whose value to look upkey
- the key of the value to look up in that mapdefaultValue
- what to return if the value is null or if the
conversion failspublic static boolean getBooleanValue(java.util.Map map, java.lang.Object key)
If the value is a Boolean
its value is returned.
If the value is a String
and it equals 'true' ignoring case
then true
is returned, otherwise false
.
If the value is a Number
an integer zero value returns
false
and non-zero returns true
.
Otherwise, false
is returned.
map
- the map to usekey
- the key to look upfalse
if null map inputpublic static byte getByteValue(java.util.Map map, java.lang.Object key)
The byte is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0
if null map inputpublic static short getShortValue(java.util.Map map, java.lang.Object key)
The short is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0
if null map inputpublic static int getIntValue(java.util.Map map, java.lang.Object key)
The int is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0
if null map inputpublic static long getLongValue(java.util.Map map, java.lang.Object key)
The long is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0L
if null map inputpublic static float getFloatValue(java.util.Map map, java.lang.Object key)
The float is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0.0F
if null map inputpublic static double getDoubleValue(java.util.Map map, java.lang.Object key)
The double is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look up0.0
if null map inputpublic static boolean getBooleanValue(java.util.Map map, java.lang.Object key, boolean defaultValue)
If the value is a Boolean
its value is returned.
If the value is a String
and it equals 'true' ignoring case
then true
is returned, otherwise false
.
If the value is a Number
an integer zero value returns
false
and non-zero returns true
.
Otherwise, defaultValue
is returned.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static byte getByteValue(java.util.Map map, java.lang.Object key, byte defaultValue)
The byte is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static short getShortValue(java.util.Map map, java.lang.Object key, short defaultValue)
The short is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static int getIntValue(java.util.Map map, java.lang.Object key, int defaultValue)
The int is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static long getLongValue(java.util.Map map, java.lang.Object key, long defaultValue)
The long is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static float getFloatValue(java.util.Map map, java.lang.Object key, float defaultValue)
The float is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static double getDoubleValue(java.util.Map map, java.lang.Object key, double defaultValue)
The double is obtained from the results of getNumber(Map,Object)
.
map
- the map to usekey
- the key to look updefaultValue
- return if the value is null or if the
conversion failsdefaultValue
if null map inputpublic static java.util.Properties toProperties(java.util.Map map)
map
- the map to convert to a Properties object, may not be nullpublic static java.util.Map toMap(java.util.ResourceBundle resourceBundle)
resourceBundle
- the resource bundle to convert, may not be nulljava.lang.NullPointerException
- if the bundle is nullpublic static void verbosePrint(java.io.PrintStream out, java.lang.Object label, java.util.Map map)
This method prints a nicely formatted String describing the Map. Each map entry will be printed with key and value. When the value is a Map, recursive behaviour occurs.
This method is NOT thread-safe in any special way. You must manually synchronize on either this class or the stream as required.
out
- the stream to print to, must not be nulllabel
- The label to be used, may be null
.
If null
, the label is not output.
It typically represents the name of the property in a bean or similar.map
- The map to print, may be null
.
If null
, the text 'null' is output.java.lang.NullPointerException
- if the stream is null
public static void debugPrint(java.io.PrintStream out, java.lang.Object label, java.util.Map map)
This method prints a nicely formatted String describing the Map. Each map entry will be printed with key, value and value classname. When the value is a Map, recursive behaviour occurs.
This method is NOT thread-safe in any special way. You must manually synchronize on either this class or the stream as required.
out
- the stream to print to, must not be nulllabel
- The label to be used, may be null
.
If null
, the label is not output.
It typically represents the name of the property in a bean or similar.map
- The map to print, may be null
.
If null
, the text 'null' is output.java.lang.NullPointerException
- if the stream is null
public static java.util.Map invertMap(java.util.Map map)
This operation assumes that the inverse mapping is well defined. If the input map had multiple entries with the same value mapped to different keys, the returned map will map one of those keys to the value, but the exact key which will be mapped is undefined.
map
- the map to invert, may not be nulljava.lang.NullPointerException
- if the map is nullpublic static void safeAddToMap(java.util.Map map, java.lang.Object key, java.lang.Object value) throws java.lang.NullPointerException
This method checks the value being added to the map, and if it is null it is replaced by an empty string.
This could be useful if the map does not accept null values, or for receiving data from a source that may provide null or empty string which should be held in the same way in the map.
Keys are not validated.
map
- the map to add to, may not be nullkey
- the keyvalue
- the value, null converted to ""java.lang.NullPointerException
- if the map is nullpublic static java.util.Map putAll(java.util.Map map, java.lang.Object[] array)
This method is an alternative to the Map.putAll(java.util.Map)
method and constructors. It allows you to build a map from an object array
of various possible styles.
If the first entry in the object array implements Map.Entry
or KeyValue
then the key and value are added from that object.
If the first entry in the object array is an object array itself, then
it is assumed that index 0 in the sub-array is the key and index 1 is the value.
Otherwise, the array is treated as keys and values in alternate indices.
For example, to create a color map:
Map colorMap = MapUtils.putAll(new HashMap(), new String[][] { {"RED", "#FF0000"}, {"GREEN", "#00FF00"}, {"BLUE", "#0000FF"} });or:
Map colorMap = MapUtils.putAll(new HashMap(), new String[] { "RED", "#FF0000", "GREEN", "#00FF00", "BLUE", "#0000FF" });or:
Map colorMap = MapUtils.putAll(new HashMap(), new Map.Entry[] { new DefaultMapEntry("RED", "#FF0000"), new DefaultMapEntry("GREEN", "#00FF00"), new DefaultMapEntry("BLUE", "#0000FF") });
map
- the map to populate, must not be nullarray
- an array to populate from, null ignoredjava.lang.NullPointerException
- if map is nulljava.lang.IllegalArgumentException
- if sub-array or entry matching used and an
entry is invalidjava.lang.ClassCastException
- if the array contents is mixedpublic static boolean isEmpty(java.util.Map map)
Null returns true.
map
- the map to check, may be nullpublic static boolean isNotEmpty(java.util.Map map)
Null returns false.
map
- the map to check, may be nullpublic static java.util.Map synchronizedMap(java.util.Map map)
You must manually synchronize on the returned buffer's iterator to avoid non-deterministic behavior:
Map m = MapUtils.synchronizedMap(myMap); Set s = m.keySet(); // outside synchronized block synchronized (m) { // synchronized on MAP! Iterator i = s.iterator(); while (i.hasNext()) { process (i.next()); } }This method uses the implementation in
Collections
.map
- the map to synchronize, must not be nulljava.lang.IllegalArgumentException
- if the map is nullpublic static java.util.Map unmodifiableMap(java.util.Map map)
This method uses the implementation in the decorators subpackage.
map
- the map to make unmodifiable, must not be nulljava.lang.IllegalArgumentException
- if the map is nullpublic static java.util.Map predicatedMap(java.util.Map map, Predicate keyPred, Predicate valuePred)
Only objects that pass the tests in the given predicates can be added to the map. Trying to add an invalid object results in an IllegalArgumentException. Keys must pass the key predicate, values must pass the value predicate. It is important not to use the original map after invoking this method, as it is a backdoor for adding invalid objects.
map
- the map to predicate, must not be nullkeyPred
- the predicate for keys, null means no checkvaluePred
- the predicate for values, null means no checkjava.lang.IllegalArgumentException
- if the Map is nullpublic static java.util.Map typedMap(java.util.Map map, java.lang.Class keyType, java.lang.Class valueType)
Only keys and values of the specified types can be added to the map.
map
- the map to limit to a specific type, must not be nullkeyType
- the type of keys which may be added to the map, must not be nullvalueType
- the type of values which may be added to the map, must not be nulljava.lang.IllegalArgumentException
- if the Map or Class is nullpublic static java.util.Map transformedMap(java.util.Map map, Transformer keyTransformer, Transformer valueTransformer)
This method returns a new map (decorating the specified map) that
will transform any new entries added to it.
Existing entries in the specified map will not be transformed.
If you want that behaviour, see TransformedMap.decorateTransform(java.util.Map, org.apache.commons.collections.Transformer, org.apache.commons.collections.Transformer)
.
Each object is passed through the transformers as it is added to the Map. It is important not to use the original map after invoking this method, as it is a backdoor for adding untransformed objects.
If there are any elements already in the map being decorated, they are NOT transformed.
map
- the map to transform, must not be null, typically emptykeyTransformer
- the transformer for the map keys, null means no transformationvalueTransformer
- the transformer for the map values, null means no transformationjava.lang.IllegalArgumentException
- if the Map is nullpublic static java.util.Map fixedSizeMap(java.util.Map map)
Map.put(Object,Object)
method).map
- the map whose size to fix, must not be nulljava.lang.IllegalArgumentException
- if the Map is nullpublic static java.util.Map lazyMap(java.util.Map map, Factory factory)
When the key passed to the returned map's Map.get(Object)
method is not present in the map, then the factory will be used
to create a new object and that object will become the value
associated with that key.
For instance:
Factory factory = new Factory() { public Object create() { return new Date(); } } Map lazyMap = MapUtils.lazyMap(new HashMap(), factory); Object obj = lazyMap.get("test");After the above code is executed,
obj
will contain
a new Date
instance. Furthermore, that Date
instance is the value for the "test"
key in the map.map
- the map to make lazy, must not be nullfactory
- the factory for creating new objects, must not be nulljava.lang.IllegalArgumentException
- if the Map or Factory is nullpublic static java.util.Map lazyMap(java.util.Map map, Transformer transformerFactory)
When the key passed to the returned map's Map.get(Object)
method is not present in the map, then the factory will be used
to create a new object and that object will become the value
associated with that key. The factory is a Transformer
that will be passed the key which it must transform into the value.
For instance:
Transformer factory = new Transformer() { public Object transform(Object mapKey) { return new File(mapKey); } } Map lazyMap = MapUtils.lazyMap(new HashMap(), factory); Object obj = lazyMap.get("C:/dev");After the above code is executed,
obj
will contain
a new File
instance for the C drive dev directory.
Furthermore, that File
instance is the value for the
"C:/dev"
key in the map.
If a lazy map is wrapped by a synchronized map, the result is a simple synchronized cache. When an object is not is the cache, the cache itself calls back to the factory Transformer to populate itself, all within the same synchronized block.
map
- the map to make lazy, must not be nulltransformerFactory
- the factory for creating new objects, must not be nulljava.lang.IllegalArgumentException
- if the Map or Transformer is nullpublic static java.util.Map orderedMap(java.util.Map map)
If a key is added twice, the order is determined by the first add. The order is observed through the keySet, values and entrySet.
map
- the map to order, must not be nulljava.lang.IllegalArgumentException
- if the Map is nullpublic static java.util.Map multiValueMap(java.util.Map map)
map
- the map to decorateMultiValueMap
public static java.util.Map multiValueMap(java.util.Map map, java.lang.Class collectionClass)
map
- the map to decoratecollectionClass
- the type of collections to return from the map (must contain public no-arg constructor
and extend Collection).MultiValueMap
public static java.util.Map multiValueMap(java.util.Map map, Factory collectionFactory)
map
- the map to decoratecollectionFactory
- a factor which creates collection objectsMultiValueMap
public static java.util.Map synchronizedSortedMap(java.util.SortedMap map)
You must manually synchronize on the returned buffer's iterator to avoid non-deterministic behavior:
Map m = MapUtils.synchronizedSortedMap(myMap); Set s = m.keySet(); // outside synchronized block synchronized (m) { // synchronized on MAP! Iterator i = s.iterator(); while (i.hasNext()) { process (i.next()); } }This method uses the implementation in
Collections
.map
- the map to synchronize, must not be nulljava.lang.IllegalArgumentException
- if the map is nullpublic static java.util.Map unmodifiableSortedMap(java.util.SortedMap map)
This method uses the implementation in the decorators subpackage.
map
- the sorted map to make unmodifiable, must not be nulljava.lang.IllegalArgumentException
- if the map is nullpublic static java.util.SortedMap predicatedSortedMap(java.util.SortedMap map, Predicate keyPred, Predicate valuePred)
Only objects that pass the tests in the given predicates can be added to the map. Trying to add an invalid object results in an IllegalArgumentException. Keys must pass the key predicate, values must pass the value predicate. It is important not to use the original map after invoking this method, as it is a backdoor for adding invalid objects.
map
- the map to predicate, must not be nullkeyPred
- the predicate for keys, null means no checkvaluePred
- the predicate for values, null means no checkjava.lang.IllegalArgumentException
- if the SortedMap is nullpublic static java.util.SortedMap typedSortedMap(java.util.SortedMap map, java.lang.Class keyType, java.lang.Class valueType)
Only keys and values of the specified types can be added to the map.
map
- the map to limit to a specific type, must not be nullkeyType
- the type of keys which may be added to the map, must not be nullvalueType
- the type of values which may be added to the map, must not be nullpublic static java.util.SortedMap transformedSortedMap(java.util.SortedMap map, Transformer keyTransformer, Transformer valueTransformer)
This method returns a new sorted map (decorating the specified map) that
will transform any new entries added to it.
Existing entries in the specified map will not be transformed.
If you want that behaviour, see TransformedSortedMap.decorateTransform(java.util.SortedMap, org.apache.commons.collections.Transformer, org.apache.commons.collections.Transformer)
.
Each object is passed through the transformers as it is added to the Map. It is important not to use the original map after invoking this method, as it is a backdoor for adding untransformed objects.
If there are any elements already in the map being decorated, they are NOT transformed.
map
- the map to transform, must not be null, typically emptykeyTransformer
- the transformer for the map keys, null means no transformationvalueTransformer
- the transformer for the map values, null means no transformationjava.lang.IllegalArgumentException
- if the SortedMap is nullpublic static java.util.SortedMap fixedSizeSortedMap(java.util.SortedMap map)
Map.put(Object,Object)
method).map
- the map whose size to fix, must not be nulljava.lang.IllegalArgumentException
- if the SortedMap is nullpublic static java.util.SortedMap lazySortedMap(java.util.SortedMap map, Factory factory)
When the key passed to the returned map's Map.get(Object)
method is not present in the map, then the factory will be used
to create a new object and that object will become the value
associated with that key.
For instance:
Factory factory = new Factory() { public Object create() { return new Date(); } } SortedMap lazy = MapUtils.lazySortedMap(new TreeMap(), factory); Object obj = lazy.get("test");After the above code is executed,
obj
will contain
a new Date
instance. Furthermore, that Date
instance is the value for the "test"
key.map
- the map to make lazy, must not be nullfactory
- the factory for creating new objects, must not be nulljava.lang.IllegalArgumentException
- if the SortedMap or Factory is nullpublic static java.util.SortedMap lazySortedMap(java.util.SortedMap map, Transformer transformerFactory)
When the key passed to the returned map's Map.get(Object)
method is not present in the map, then the factory will be used
to create a new object and that object will become the value
associated with that key. The factory is a Transformer
that will be passed the key which it must transform into the value.
For instance:
Transformer factory = new Transformer() { public Object transform(Object mapKey) { return new File(mapKey); } } SortedMap lazy = MapUtils.lazySortedMap(new TreeMap(), factory); Object obj = lazy.get("C:/dev");After the above code is executed,
obj
will contain
a new File
instance for the C drive dev directory.
Furthermore, that File
instance is the value for the
"C:/dev"
key in the map.
If a lazy map is wrapped by a synchronized map, the result is a simple synchronized cache. When an object is not is the cache, the cache itself calls back to the factory Transformer to populate itself, all within the same synchronized block.
map
- the map to make lazy, must not be nulltransformerFactory
- the factory for creating new objects, must not be nulljava.lang.IllegalArgumentException
- if the Map or Transformer is nullCopyright © 2010 - 2020 Adobe. All Rights Reserved