BaseConnection.java

/*
 * Copyright (C) 2010, Google Inc.
 * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.transport;

import java.io.StringWriter;
import java.io.Writer;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;

import org.eclipse.jgit.errors.TransportException;
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.Ref;

/**
 * Base helper class for implementing operations connections.
 *
 * @see BasePackConnection
 * @see BaseFetchConnection
 */
public abstract class BaseConnection implements Connection {
    private Map<String, Ref> advertisedRefs = Collections.emptyMap();

    private String peerUserAgent;

    private boolean startedOperation;

    private Writer messageWriter;

    /** {@inheritDoc} */
    @Override
    public Map<String, Ref> getRefsMap() {
        return advertisedRefs;
    }

    /** {@inheritDoc} */
    @Override
    public final Collection<Ref> getRefs() {
        return advertisedRefs.values();
    }

    /** {@inheritDoc} */
    @Override
    public final Ref getRef(String name) {
        return advertisedRefs.get(name);
    }

    /** {@inheritDoc} */
    @Override
    public String getMessages() {
        return messageWriter != null ? messageWriter.toString() : ""; //$NON-NLS-1$
    }

    /**
     * {@inheritDoc}
     *
     * User agent advertised by the remote server.
     * @since 4.0
     */
    @Override
    public String getPeerUserAgent() {
        return peerUserAgent;
    }

    /**
     * Remember the remote peer's agent.
     *
     * @param agent
     *            remote peer agent string.
     * @since 4.0
     */
    protected void setPeerUserAgent(String agent) {
        peerUserAgent = agent;
    }

    /** {@inheritDoc} */
    @Override
    public abstract void close();

    /**
     * Denote the list of refs available on the remote repository.
     * <p>
     * Implementors should invoke this method once they have obtained the refs
     * that are available from the remote repository.
     *
     * @param all
     *            the complete list of refs the remote has to offer. This map
     *            will be wrapped in an unmodifiable way to protect it, but it
     *            does not get copied.
     */
    protected void available(Map<String, Ref> all) {
        advertisedRefs = Collections.unmodifiableMap(all);
    }

    /**
     * Helper method for ensuring one-operation per connection. Check whether
     * operation was already marked as started, and mark it as started.
     *
     * @throws org.eclipse.jgit.errors.TransportException
     *             if operation was already marked as started.
     */
    protected void markStartedOperation() throws TransportException {
        if (startedOperation)
            throw new TransportException(
                    JGitText.get().onlyOneOperationCallPerConnectionIsSupported);
        startedOperation = true;
    }

    /**
     * Get the writer that buffers messages from the remote side.
     *
     * @return writer to store messages from the remote.
     */
    protected Writer getMessageWriter() {
        if (messageWriter == null)
            setMessageWriter(new StringWriter());
        return messageWriter;
    }

    /**
     * Set the writer that buffers messages from the remote side.
     *
     * @param writer
     *            the writer that messages will be delivered to. The writer's
     *            {@code toString()} method should be overridden to return the
     *            complete contents.
     */
    protected void setMessageWriter(Writer writer) {
        if (messageWriter != null)
            throw new IllegalStateException(JGitText.get().writerAlreadyInitialized);
        messageWriter = writer;
    }
}