Module java.base
Package java.util.jar

Class Attributes

java.lang.Object
java.util.jar.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 Class Summary

    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>

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected Map<Object,​Object>
    map
    The attribute name-value mappings.

  • Constructor Summary

    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.

  • Method Summary

    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 object to the underlying 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

  • Field Details

    • map

      protected Map<Object,​Object> map
      The attribute name-value mappings.

  • Constructor Details

    • 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

  • Method Details

    • 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 object to the underlying map for equality. Returns true if the given object is also a Map and the two maps 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