org.redmine.ta.internal.comm.Communicators Maven / Gradle / Ivy

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package org.redmine.ta.internal.comm;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;

import org.apache.http.HttpResponse;
import org.redmine.ta.RedmineException;
import org.redmine.ta.RedmineTransportException;

/**
 * Communicator utilities.
 * 
 * @author maxkar
 * 
 */
public final class Communicators {
	private static final ContentHandler IDENTITY_HANDLER = new ContentHandler() {
		@Override
		public Object processContent(Object content) throws RedmineException {
			return content;
		}
	};

	private static final ContentHandler TRANSPORT_DECODER = new TransportDecoder();

	private static final ContentHandler CHARACTER_DECODER = new ContentHandler() {
		@Override
		public Reader processContent(BasicHttpResponse content)
				throws RedmineException {
			final String charset = content.getCharset();
			try {
				return new InputStreamReader(content.getStream(), charset);
			} catch (UnsupportedEncodingException e) {
				throw new RedmineTransportException(
						"Unsupported response charset " + charset, e);
			}
		}
	};

	private static final ContentHandler READ_CHARS = new ContentHandler() {
		@Override
		public String processContent(Reader content) throws RedmineException {
			return readAll(content);
		}
	};

	private static final ContentHandler CHAR_CONTENT_READER = compose(
			READ_CHARS, CHARACTER_DECODER);

	static String readAll(Reader r) throws RedmineException {
		final StringWriter writer = new StringWriter();
		final char[] buffer = new char[4096];
		int readed;
		try {
			while ((readed = r.read(buffer)) > 0) {
				writer.write(buffer, 0, readed);
			}
			r.close();
			writer.close();
			return writer.toString();
		} catch (IOException e) {
			throw new RedmineTransportException(e);
		}
	}

	public static  SimpleCommunicator simplify(
			Communicator communicator, ContentHandler handler) {
		return new BasicSimplifier(handler, communicator);
	}

	@SuppressWarnings("unchecked")
	public static  ContentHandler identityHandler() {
		return (ContentHandler) IDENTITY_HANDLER;
	}

	public static ContentHandler contentReader() {
		return CHAR_CONTENT_READER;
	}

	public static  ContentHandler compose(
			ContentHandler cont1, ContentHandler cont2) {
		return new ComposingHandler(cont1, cont2);
	}

	public static  Communicator fmap(Communicator comm,
			ContentHandler handler) {
		return new FmapCommunicator(handler, comm);
	}

	public static ContentHandler transportDecoder() {
		return TRANSPORT_DECODER;
	}

	public static ContentHandler characterDecoder() {
		return CHARACTER_DECODER;
	}

	public static ContentHandler readChars() {
		return READ_CHARS;
	}
}