1 package org.e2etrace.trace;
2
3 /*
4 * Copyright 2006 Gunther Popp
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 /**
20 * Root trace step for {@link org.e2etrace.trace.ITraceSession}.
21 * <p>
22 *
23 * Each trace session contains one implicit trace step that serves as root of
24 * the tree of "real" trace steps. The duration of this trace step is by
25 * definition the accumulated duration of all children. In additon, the isolated
26 * duration of this step is by definion 0ms.
27 * <p>
28 *
29 * In practice, an instance of the root step represents a complete service
30 * call. The children of the root step are the single execution steps of the
31 * service.
32 * <p>
33 *
34 * A root step can savely be added as child to any other trace step (e.g. if a
35 * client invokes a remote service, the root step of the service can be added
36 * to any trace step of the client). However, if a client spawns multiple services
37 * asynchronously and waits until all of them return, the isolated duration of
38 * the client step will return a meaningless value (since the overall processing
39 * time of the parallel services exceeds the execution time of the client step).<p>
40 *
41 * This class is only instantiated by implementations of
42 * {@link org.e2etrace.trace.ITraceSession}
43 *
44 * @author Gunther Popp
45 *
46 */
47 public class TraceSessionRootStep extends AbstractTraceStep {
48
49 private static final long serialVersionUID = 1L;
50
51 /**
52 * Constructor.
53 *
54 * @param id ID of the root step
55 */
56 public TraceSessionRootStep(TraceSessionRootStepId id) {
57 super(id);
58 }
59
60 /**
61 * Returns the overall duration of this TraceStep and all children.
62 * <p>
63 *
64 * @return duration in ms
65 */
66 public long getDuration() {
67 long duration;
68 ITraceStep[] children;
69
70 // Sum up the durations of all direct children of the root
71 // step
72 children = this.getChildren();
73 duration = 0;
74 for (int i = 0; i < children.length; i++) {
75 duration += children[i].getDuration();
76 }
77
78 return duration;
79 }
80
81 /**
82 * The isolated duration of the root step is by definition 0ms.
83 *
84 * @return duration of this TraceStep in ms (-1:<code>leave</code> has not
85 * been called yet)
86 */
87 public long getIsolatedDuration() {
88 return 0;
89 }
90
91 /** {@inheritDoc} */
92 public void enter() throws IllegalStateException {
93 // This method is intentionally left blank
94
95 }
96
97 /**
98 * Checks, if the current trace step is active.
99 * <p>
100 *
101 * The session root step is always active by definition.
102 * <p>
103 *
104 * @return true
105 */
106 public boolean isActive() {
107 return true;
108 }
109
110 /** {@inheritDoc} */
111 public void leave() throws IllegalStateException {
112 // Forward the call to all children
113 leaveAllChildren();
114
115 }
116
117 }