1 package org.sonatype.aether;
2
3 /*******************************************************************************
4 * Copyright (c) 2010-2011 Sonatype, Inc.
5 * All rights reserved. This program and the accompanying materials
6 * are made available under the terms of the Eclipse Public License v1.0
7 * which accompanies this distribution, and is available at
8 * http://www.eclipse.org/legal/epl-v10.html
9 *******************************************************************************/
10
11 /**
12 * A trace of nested requests that are performed by the repository system. This trace information can be used to
13 * correlate repository events with higher level operations in the application code that eventually caused the events. A
14 * single trace can carry an arbitrary object as data which is meant to describe a request/operation that is currently
15 * executed. For call hierarchies within the repository system itself, this data will usually be the {@code *Request}
16 * object that is currently processed. When invoking methods on the repository system, client code may provide a request
17 * trace that has been prepopulated with whatever data is useful for the application to indicate its state for later
18 * evaluation when processing the repository events.
19 *
20 * @author Benjamin Bentmann
21 * @see RepositoryEvent#getTrace()
22 */
23 public interface RequestTrace
24 {
25
26 /**
27 * Gets the data associated with this trace.
28 *
29 * @return The data associated with this trace or {@code null}.
30 */
31 Object getData();
32
33 /**
34 * Gets the parent of this trace.
35 *
36 * @return The parent of this trace or {@code null} if this is the root of the trace stack.
37 */
38 RequestTrace getParent();
39
40 /**
41 * Creates a new child of this trace.
42 *
43 * @param data The data to associate with the child, may be {@code null}.
44 * @return The child trace, never {@code null}.
45 */
46 RequestTrace newChild( Object data );
47
48 }