package org.bouncycastle.x509;

import org.bouncycastle.x509.util.StreamParser;
import org.bouncycastle.x509.util.StreamParsingException;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Provider;
import java.util.Collection;

This class allows access to different implementations for reading X.509
objects from streams.

A X509StreamParser is used to read a collection of objects or a single object
of a certain X.509 object structure. E.g. one X509StreamParser can read
certificates, another one CRLs, certification paths, attribute certificates
and so on. The kind of object structure is specified with the
algorithm parameter to the getInstance methods.
 Implementations must implement the X509StreamParserSpi. /**
 *
 * This class allows access to different implementations for reading X.509
 * objects from streams.
 * <p>
 * A X509StreamParser is used to read a collection of objects or a single object
 * of a certain X.509 object structure. E.g. one X509StreamParser can read
 * certificates, another one CRLs, certification paths, attribute certificates
 * and so on. The kind of object structure is specified with the
 * <code>algorithm</code> parameter to the <code>getInstance</code> methods.
 * <p>
 * Implementations must implement the
 * {@link org.bouncycastle.x509.X509StreamParserSpi}.
 */
public class X509StreamParser
    implements StreamParser
{
    
Generates a StreamParser object that implements the specified type. If
the default provider package provides an implementation of the requested
type, an instance of StreamParser containing that implementation is
returned. If the type is not available in the default package, other
packages are searched.
Params:
type – 
           The name of the requested X.509 object type.
Throws:
NoSuchParserException – 
               if the requested type is not available in the default
               provider package or any of the other provider packages
               that were searched.
Returns:
a StreamParser object for the specified type./**
     * Generates a StreamParser object that implements the specified type. If
     * the default provider package provides an implementation of the requested
     * type, an instance of StreamParser containing that implementation is
     * returned. If the type is not available in the default package, other
     * packages are searched.
     *
     * @param type
     *            The name of the requested X.509 object type.
     * @return a StreamParser object for the specified type.
     *
     * @exception NoSuchParserException
     *                if the requested type is not available in the default
     *                provider package or any of the other provider packages
     *                that were searched.
     */
    public static X509StreamParser getInstance(String type)
        throws NoSuchParserException
    {
        try
        {
            X509Util.Implementation impl = X509Util.getImplementation("X509StreamParser", type);

            return createParser(impl);
        }
        catch (NoSuchAlgorithmException e)
        {
            throw new NoSuchParserException(e.getMessage());
        }
    }

    
Generates a X509StreamParser object for the specified type from the
specified provider.
Params:
type – 
           the name of the requested X.509 object type.
provider – 
           the name of the provider.
Throws:
NoSuchParserException – 
               if the type is not available from the specified provider.
NoSuchProviderException – 
               if the provider can not be found.
See Also:
Provider
Returns:
a X509StreamParser object for the specified type./**
     * Generates a X509StreamParser object for the specified type from the
     * specified provider.
     *
     * @param type
     *            the name of the requested X.509 object type.
     * @param provider
     *            the name of the provider.
     *
     * @return a X509StreamParser object for the specified type.
     *
     * @exception NoSuchParserException
     *                if the type is not available from the specified provider.
     *
     * @exception NoSuchProviderException
     *                if the provider can not be found.
     *
     * @see Provider
     */
    public static X509StreamParser getInstance(String type, String provider)
        throws NoSuchParserException, NoSuchProviderException
    {
        return getInstance(type, X509Util.getProvider(provider));
    }

    
Generates a X509StreamParser object for the specified type from the
specified provider.
Params:
type – 
           the name of the requested X.509 object type.
provider – 
           the Provider to use.
Throws:
NoSuchParserException – 
               if the type is not available from the specified provider.
See Also:
Provider
Returns:
a X509StreamParser object for the specified type./**
     * Generates a X509StreamParser object for the specified type from the
     * specified provider.
     *
     * @param type
     *            the name of the requested X.509 object type.
     * @param provider
     *            the Provider to use.
     *
     * @return a X509StreamParser object for the specified type.
     *
     * @exception NoSuchParserException
     *                if the type is not available from the specified provider.
     *
     * @see Provider
     */
    public static X509StreamParser getInstance(String type, Provider provider)
        throws NoSuchParserException
    {
        try
        {
            X509Util.Implementation impl = X509Util.getImplementation("X509StreamParser", type, provider);

            return createParser(impl);
        }
        catch (NoSuchAlgorithmException e)
        {
            throw new NoSuchParserException(e.getMessage());
        }
    }

    private static X509StreamParser createParser(X509Util.Implementation impl)
    {
        X509StreamParserSpi spi = (X509StreamParserSpi)impl.getEngine();

        return new X509StreamParser(impl.getProvider(), spi);
    }

    private Provider            _provider;
    private X509StreamParserSpi _spi;

    private X509StreamParser(
        Provider provider,
        X509StreamParserSpi spi)
    {
        _provider = provider;
        _spi = spi;
    }

    public Provider getProvider()
    {
        return _provider;
    }

    public void init(InputStream stream)
    {
        _spi.engineInit(stream);
    }

    public void init(byte[] data)
    {
        _spi.engineInit(new ByteArrayInputStream(data));
    }

    public Object read()
        throws StreamParsingException
    {
        return _spi.engineRead();
    }

    public Collection readAll()
        throws StreamParsingException
    {
        return _spi.engineReadAll();
    }
}