Class Attributes

All Implemented Interfaces:
Cloneable, Map<Object,​Object> 
public class Attributes
extends Object
implements Map<Object,Object>, Cloneable

The Attributes class maps Manifest attribute names to associated string values. Valid attribute names are case-insensitive, are restricted to the ASCII characters in the set [0-9a-zA-Z_-], and cannot exceed 70 characters in length. There must be a colon and a SPACE after the name; the combined length will not exceed 72 characters. Attribute values can contain any characters and will be UTF8-encoded when written to the output stream. See the JAR File Specification for more information about valid attribute names and values.

This map and its views have a predictable iteration order, namely the order that keys were inserted into the map, as with LinkedHashMap.

Since:
1.2
See Also:
Manifest

Nested Classes

Modifier and Type Class Description
static class  Attributes.Name

The Attributes.Name class represents an attribute name stored in this Map.

Nested classes/interfaces declared in interface java.util.Map

Map.Entry<K,​V>

Fields

Modifier and Type Field Description
protected Map<Object,​Object> map

The attribute name-value mappings.

Constructors

Constructor Description
Attributes()

Constructs a new, empty Attributes object with default size.
Attributes​(int size)

Constructs a new, empty Attributes object with the specified initial size.
Attributes​(Attributes attr)

Constructs a new Attributes object with the same attribute name-value mappings as in the specified Attributes.

Methods

Modifier and Type Method Description
void clear()

Removes all attributes from this Map.
Object clone()

Returns a copy of the Attributes, implemented as follows:
boolean containsKey​(Object name)

Returns true if this Map contains the specified attribute name (key).
boolean containsValue​(Object value)

Returns true if this Map maps one or more attribute names (keys) to the specified value.
Set<Map.Entry<Object,​Object>> entrySet()

Returns a Collection view of the attribute name-value mappings contained in this Map.
boolean equals​(Object o)

Compares the specified Attributes object with this Map for equality.
Object get​(Object name)

Returns the value of the specified attribute name, or null if the attribute name was not found.
String getValue​(String name)

Returns the value of the specified attribute name, specified as a string, or null if the attribute was not found.
String getValue​(Attributes.Name name)

Returns the value of the specified Attributes.Name, or null if the attribute was not found.
int hashCode()

Returns the hash code value for this Map.
boolean isEmpty()

Returns true if this Map contains no attributes.
Set<Object> keySet()

Returns a Set view of the attribute names (keys) contained in this Map.
Object put​(Object name, Object value)

Associates the specified value with the specified attribute name (key) in this Map.
void putAll​(Map<?,​?> attr)

Copies all of the attribute name-value mappings from the specified Attributes to this Map.
String putValue​(String name, String value)

Associates the specified value with the specified attribute name, specified as a String.
Object remove​(Object name)

Removes the attribute with the specified name (key) from this Map.
int size()

Returns the number of attributes in this Map.
Collection<Object> values()

Returns a Collection view of the attribute values contained in this Map.

Methods declared in class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods declared in interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Fields

map

protected Map<Object,Object> map

The attribute name-value mappings.

Constructors

Attributes

public Attributes()

Constructs a new, empty Attributes object with default size.

Attributes

public Attributes(int size)

Constructs a new, empty Attributes object with the specified initial size.

Parameters:
size - the initial number of attributes

Attributes

public Attributes(Attributes attr)

Constructs a new Attributes object with the same attribute name-value mappings as in the specified Attributes.

Parameters:
attr - the specified Attributes

Methods

get

public Object get(Object name)

Returns the value of the specified attribute name, or null if the attribute name was not found.

Specified by:
get in interface Map<Object,​Object>
Parameters:
name - the attribute name
Returns:
the value of the specified attribute name, or null if not found.

getValue

public String getValue(String name)

Returns the value of the specified attribute name, specified as a string, or null if the attribute was not found. The attribute name is case-insensitive.

This method is defined as: 

return (String)get(new Attributes.Name((String)name));
Parameters:
name - the attribute name as a string
Returns:
the String value of the specified attribute name, or null if not found.
Throws:
IllegalArgumentException - if the attribute name is invalid

getValue

public String getValue(Attributes.Name name)

Returns the value of the specified Attributes.Name, or null if the attribute was not found.

This method is defined as: 

return (String)get(name);
Parameters:
name - the Attributes.Name object
Returns:
the String value of the specified Attribute.Name, or null if not found.

put

public Object put(Object name,
                  Object value)

Associates the specified value with the specified attribute name (key) in this Map. If the Map previously contained a mapping for the attribute name, the old value is replaced.

Specified by:
put in interface Map<Object,​Object>
Parameters:
name - the attribute name
value - the attribute value
Returns:
the previous value of the attribute, or null if none
Throws:
ClassCastException - if the name is not a Attributes.Name or the value is not a String

putValue

public String putValue(String name,
                       String value)

Associates the specified value with the specified attribute name, specified as a String. The attributes name is case-insensitive. If the Map previously contained a mapping for the attribute name, the old value is replaced.

This method is defined as: 

return (String)put(new Attributes.Name(name), value);
Parameters:
name - the attribute name as a string
value - the attribute value
Returns:
the previous value of the attribute, or null if none
Throws:
IllegalArgumentException - if the attribute name is invalid

remove

public Object remove(Object name)

Removes the attribute with the specified name (key) from this Map. Returns the previous attribute value, or null if none.

Specified by:
remove in interface Map<Object,​Object>
Parameters:
name - attribute name
Returns:
the previous value of the attribute, or null if none

containsValue

public boolean containsValue(Object value)

Returns true if this Map maps one or more attribute names (keys) to the specified value.

Specified by:
containsValue in interface Map<Object,​Object>
Parameters:
value - the attribute value
Returns:
true if this Map maps one or more attribute names to the specified value

containsKey

public boolean containsKey(Object name)

Returns true if this Map contains the specified attribute name (key).

Specified by:
containsKey in interface Map<Object,​Object>
Parameters:
name - the attribute name
Returns:
true if this Map contains the specified attribute name

putAll

public void putAll(Map<?,​?> attr)

Copies all of the attribute name-value mappings from the specified Attributes to this Map. Duplicate mappings will be replaced.

Specified by:
putAll in interface Map<Object,​Object>
Parameters:
attr - the Attributes to be stored in this map
Throws:
ClassCastException - if attr is not an Attributes

clear

public void clear()

Removes all attributes from this Map.

Specified by:
clear in interface Map<Object,​Object>

size

public int size()

Returns the number of attributes in this Map.

Specified by:
size in interface Map<Object,​Object>
Returns:
the number of key-value mappings in this map

isEmpty

public boolean isEmpty()

Returns true if this Map contains no attributes.

Specified by:
isEmpty in interface Map<Object,​Object>
Returns:
true if this map contains no key-value mappings

keySet

public Set<Object> keySet()

Returns a Set view of the attribute names (keys) contained in this Map.

Specified by:
keySet in interface Map<Object,​Object>
Returns:
a set view of the keys contained in this map

values

public Collection<Object> values()

Returns a Collection view of the attribute values contained in this Map.

Specified by:
values in interface Map<Object,​Object>
Returns:
a collection view of the values contained in this map

entrySet

public Set<Map.Entry<Object,Object>> entrySet()

Returns a Collection view of the attribute name-value mappings contained in this Map.

Specified by:
entrySet in interface Map<Object,​Object>
Returns:
a set view of the mappings contained in this map

equals

public boolean equals(Object o)

Compares the specified Attributes object with this Map for equality. Returns true if the given object is also an instance of Attributes and the two Attributes objects represent the same mappings.

Specified by:
equals in interface Map<Object,​Object>
Overrides:
equals in class Object
Parameters:
o - the Object to be compared
Returns:
true if the specified Object is equal to this Map
See Also:
Object.hashCode(), HashMap

hashCode

public int hashCode()

Returns the hash code value for this Map.

Specified by:
hashCode in interface Map<Object,​Object>
Overrides:
hashCode in class Object
Returns:
a hash code value for this object.
See Also:
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

clone

public Object clone()

Returns a copy of the Attributes, implemented as follows: 

public Object clone() { return new Attributes(this); }
Since the attribute names and values are themselves immutable, the Attributes returned can be safely modified without affecting the original.

Overrides:
clone in class Object
Returns:
a clone of this instance.
See Also:
Cloneable

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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/jar/Attributes.html