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package java.nio.charset.spi;

import java.nio.charset.Charset;
import java.util.Iterator;



Charset service-provider class.

 A charset provider is a concrete subclass of this class that has a zero-argument constructor and some number of associated charset implementation classes. Charset providers may be installed in an instance of the Java platform as extensions. Providers may also be made available by adding them to the applet or application class path or by some other platform-specific means. Charset providers are looked up via the current thread's context class
loader. 
 A charset provider identifies itself with a provider-configuration file named java.nio.charset.spi.CharsetProvider in the resource directory META-INF/services. The file should contain a list of fully-qualified concrete charset-provider class names, one per line. A line is terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a line feed. Space and tab characters surrounding each name, as well as blank lines, are ignored. The comment character is '#' ('\u0023'); on
each line all characters following the first comment character are ignored.
The file must be encoded in UTF-8.

 If a particular concrete charset provider class is named in more than
one configuration file, or is named in the same configuration file more than
once, then the duplicates will be ignored.  The configuration file naming a
particular provider need not be in the same jar file or other distribution
unit as the provider itself.  The provider must be accessible from the same
class loader that was initially queried to locate the configuration file;
this is not necessarily the class loader that loaded the file. 


Author:Mark Reinhold, JSR-51 Expert Group
See Also:
Since:1.4
/**
 * Charset service-provider class.
 *
 * <p> A charset provider is a concrete subclass of this class that has a
 * zero-argument constructor and some number of associated charset
 * implementation classes.  Charset providers may be installed in an instance
 * of the Java platform as extensions.  Providers may also be made available by
 * adding them to the applet or application class path or by some other
 * platform-specific means.  Charset providers are looked up via the current
 * thread's {@link java.lang.Thread#getContextClassLoader() context class
 * loader}.
 *
 * <p> A charset provider identifies itself with a provider-configuration file
 * named {@code java.nio.charset.spi.CharsetProvider} in the resource
 * directory {@code META-INF/services}.  The file should contain a list of
 * fully-qualified concrete charset-provider class names, one per line.  A line
 * is terminated by any one of a line feed ({@code '\n'}), a carriage return
 * ({@code '\r'}), or a carriage return followed immediately by a line feed.
 * Space and tab characters surrounding each name, as well as blank lines, are
 * ignored.  The comment character is {@code '#'} (<code>'&#92;u0023'</code>); on
 * each line all characters following the first comment character are ignored.
 * The file must be encoded in UTF-8.
 *
 * <p> If a particular concrete charset provider class is named in more than
 * one configuration file, or is named in the same configuration file more than
 * once, then the duplicates will be ignored.  The configuration file naming a
 * particular provider need not be in the same jar file or other distribution
 * unit as the provider itself.  The provider must be accessible from the same
 * class loader that was initially queried to locate the configuration file;
 * this is not necessarily the class loader that loaded the file. </p>
 *
 *
 * @author Mark Reinhold
 * @author JSR-51 Expert Group
 * @since 1.4
 *
 * @see java.nio.charset.Charset
 */

public abstract class CharsetProvider {

    private static Void checkPermission() {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null)
            sm.checkPermission(new RuntimePermission("charsetProvider"));
        return null;
    }
    private CharsetProvider(Void ignore) { }

    
Initializes a new charset provider.

Throws:
  • SecurityException –  If a security manager has been installed and it denies RuntimePermission("charsetProvider")
/**
     * Initializes a new charset provider.
     *
     * @throws  SecurityException
     *          If a security manager has been installed and it denies
     *          {@link RuntimePermission}{@code ("charsetProvider")}
     */
    protected CharsetProvider() {
        this(checkPermission());
    }

    
Creates an iterator that iterates over the charsets supported by this provider. This method is used in the implementation of the Charset.availableCharsets method. 
Returns: The new iterator
/**
     * Creates an iterator that iterates over the charsets supported by this
     * provider.  This method is used in the implementation of the {@link
     * java.nio.charset.Charset#availableCharsets Charset.availableCharsets}
     * method.
     *
     * @return  The new iterator
     */
    public abstract Iterator<Charset> charsets();

    
Retrieves a charset for the given charset name.

Params:
  • charsetName – 
        The name of the requested charset; may be either
        a canonical name or an alias
Returns: A charset object for the named charset, or null if the named charset is not supported by this provider
/**
     * Retrieves a charset for the given charset name.
     *
     * @param  charsetName
     *         The name of the requested charset; may be either
     *         a canonical name or an alias
     *
     * @return  A charset object for the named charset,
     *          or {@code null} if the named charset
     *          is not supported by this provider
     */
    public abstract Charset charsetForName(String charsetName);

}