Java Program to Implement Attribute API

This Java program is to Implement Attributes API.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. Attribute values can contain any characters and will be UTF8-encoded when written to the output stream.

Here is the source code of the Java program to Implement Attributes API. The Java program is successfully compiled and run on a Linux system. The program output is also shown below.

```
import java.util.Collection;
```
```
import java.util.Iterator;
```
```
import java.util.Map;
```
```
import java.util.Map.Entry;
```
```
import java.util.Set;
```
```
import java.util.jar.Attributes;
```
```
 
```
```
public class AttributesImpl
```
```
{ 
```
```
    private Attributes attributes;
```
```
 
```

    /** Constructs a new, empty Attributes object with default size. **/

```
    public AttributesImpl()
```
```
    {
```
```
        attributes = new Attributes();
```
```
    }
```
```
 
```
```
    /**
```

     * Constructs a new Attributes object with the same attribute name-value

     * mappings as in the specified Attributes.

```
     **/
```

    public AttributesImpl(Attributes attr)

```
    {
```

        attributes = new Attributes(attr);

```
    }
```
```
 
```
```
    /**
```

     * Constructs a new, empty Attributes object with the specified initial

```
     * size.
```
```
     **/
```
```
    public AttributesImpl(int size)
```
```
    {
```

        attributes = new Attributes(size);

```
    }
```
```
 
```

    /** Removes all attributes from this Map. **/

```
    public void clear()
```
```
    {
```
```
        attributes.clear();
```
```
    }
```
```
 
```

    /** Returns a copy of the Attributes **/

```
    public Object clone()
```
```
    {
```
```
        return attributes.clone();
```
```
    }
```
```
 
```

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

    public boolean containsKey(Object key)

```
    {
```

        return attributes.containsKey(key);

```
    }
```
```
 
```
```
    /**
```

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

```
     * specified value.
```
```
     **/
```

    public boolean containsValue(Object value)

```
    {
```

        return attributes.containsValue(value);

```
    }
```
```
 
```
```
    /**
```

     * Returns a Collection view of the attribute name-value mappings contained

```
     * in this Map.
```
```
     **/
```

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

```
    {
```
```
        return attributes.entrySet();
```
```
    }
```
```
 
```
```
    /**
```

     * Returns the value of the specified attribute name, or null if the

```
     * attribute name was not found.
```
```
     **/
```
```
    public Object get(Object key)
```
```
    {
```
```
        return attributes.get(key);
```
```
    }
```
```
 
```
```
    /**
```

     * Returns the value of the specified Attributes.Name, or null if the

```
     * attribute was not found.
```
```
     **/
```

    public String getValue(Attributes.Name name)

```
    {
```

        return attributes.getValue(name);

```
    }
```
```
 
```
```
    /**
```

     * Returns the value of the specified attribute name, specified as a string,

     * or null if the attribute was not found.

```
     **/
```
```
    public String getValue(String name)
```
```
    {
```

        return attributes.getValue(name);

```
    }
```
```
 
```

    /** Returns true if this Map contains no attributes. **/

```
    public boolean isEmpty()
```
```
    {
```
```
        return attributes.isEmpty();
```
```
    }
```
```
 
```

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

```
    public Set<Object> keySet()
```
```
    {
```
```
        return attributes.keySet();
```
```
    }
```
```
 
```
```
    /**
```

     * Associates the specified value with the specified attribute name (key) in

```
     * this Map.
```
```
     **/
```

    public Object put(Object key, Object value)

```
    {
```

        return attributes.put(key, value);

```
    }
```
```
 
```
```
    /**
```

     * Copies all of the attribute name-value mappings from the specified

```
     * Attributes to this Map.
```
```
     **/
```
```
    public void putAll(Map<?, ?> m)
```
```
    {
```
```
        attributes.putAll(m);
```
```
    }
```
```
 
```
```
    /**
```

     * Associates the specified value with the specified attribute name,

```
     * specified as a String.
```
```
     **/
```

    public String putValue(String name, String value)

```
    {
```

        return attributes.putValue(name, value);

```
    }
```
```
 
```

    /** Removes the attribute with the specified name (key) from this Map **/

```
    public Object remove(Object key)
```
```
    {
```
```
        return attributes.remove(key);
```
```
    }
```
```
 
```

    /** Returns the number of attributes in this Map. **/

```
    public int size()
```
```
    {
```
```
        return attributes.size();
```
```
    }
```
```
 
```

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

```
    public Collection<Object> values()
```
```
    {
```
```
        return attributes.values();
```
```
    }
```
```
 
```

    public static void main(String... arg)

```
    {
```

        Attributes.Name CLASS_PATH = new Attributes.Name("CLASS_PATH");

        Attributes.Name CONTENT_TYPE = new Attributes.Name("CONTENT_TYPE");

        Attributes.Name MANIFEST_VERSION = new Attributes.Name("MANIFEST_VERSION");

```
 
```

        AttributesImpl attribute = new AttributesImpl();

        attribute.put(CLASS_PATH, "root/sub_dir/class_path");

        attribute.put(CONTENT_TYPE, "UTF-8");

        attribute.put(MANIFEST_VERSION, "2");

```
 
```

        attribute.putValue("MAIN_CLASS", "TESTMAIN.java");

        System.out.println("the key set of the Attributes is ");

        Set<Object> keySet = attribute.keySet();

        Iterator<Object> itr = keySet.iterator();

```
        while (itr.hasNext())
```
```
        {
```

            System.out.print(itr.next() + "\t");

```
        }
```
```
        System.out.println();
```
```
 
```

        System.out.println("the values of the Attributes is ");

        Collection<Object> collectionValues = attribute.values();

        itr = collectionValues.iterator();

```
        while (itr.hasNext())
```
```
        {
```

            System.out.print(itr.next() + "\t");

```
        }
```
```
        System.out.println();
```

        System.out.println("the entry set of the Attributes is ");

        Iterator<Entry<Object, Object>> eitr;

        Set<Entry<Object, Object>> entrySet = attribute.entrySet();

```
        eitr = entrySet.iterator();
```
```
        while (eitr.hasNext())
```
```
        {
```

            System.out.println(eitr.next() + "\t");

```
        }
```

        System.out.println("the Attributes contains Key CLASS_PATH:" + attribute.containsKey(CLASS_PATH));

        System.out.println("the Attributes contains Value TESTMAIN.java :"

            + attribute.containsValue("TESTMAIN.java"));

        System.out.println("the size of the Attributes is " + attribute.size());

```
        attribute.clear();
```
```
        if (attribute.isEmpty())
```

            System.out.println("the Attributes is empty");

```
        else
```

            System.out.println("the Attributes is not empty");

```
    }
```
```
}
```

$ javac  AttributesImpl.java
$ java AttributesImpl
the key set of the Attributes is 
MAIN_CLASS	MANIFEST_VERSION	CONTENT_TYPE	CLASS_PATH	
the values of the Attributes is 
TESTMAIN.java	2	UTF-8	root/sub_dir/class_path	
the entry set of the Attributes is 
MAIN_CLASS=TESTMAIN.java	
MANIFEST_VERSION=2	
CONTENT_TYPE=UTF-8	
CLASS_PATH=root/sub_dir/class_path	
the Attributes contains Key CLASS_PATH:true
the Attributes contains Value TESTMAIN.java :true
the size of the Attributes is 4
the Attributes is empty

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