1 package org.lcsim.event.base;
2
3 import hep.physics.vec.BasicHep3Vector;
4 import hep.physics.vec.Hep3Vector;
5
6 import org.lcsim.detector.DetectorElement;
7 import org.lcsim.detector.DetectorElementStore;
8 import org.lcsim.detector.DetectorIdentifierHelper;
9 import org.lcsim.detector.IDetectorElement;
10 import org.lcsim.detector.IDetectorElementContainer;
11 import org.lcsim.detector.identifier.IExpandedIdentifier;
12 import org.lcsim.detector.identifier.IIdentifier;
13 import org.lcsim.detector.identifier.IIdentifierHelper;
14 import org.lcsim.event.EventHeader.LCMetaData;
15 import org.lcsim.event.Hit;
16 import org.lcsim.geometry.IDDecoder;
17 import org.lcsim.geometry.Subdetector;
18 import org.lcsim.geometry.subdetector.BarrelEndcapFlag;
19
20 /**
21 * This is a base class for hit-like objects in a detector.
22 *
23 * @author Jeremy McCormick <jeremym@slac.stanford.edu>
24 */
25 public abstract class BaseHit implements Hit {
26
27 protected LCMetaData metaData;
28 protected IExpandedIdentifier expandedID;
29 protected IIdentifier packedID;
30 protected IDetectorElement detectorElement;
31 protected Hep3Vector positionVec;
32
33 /**
34 * Get the metadata associated with this hit.
35 * @return The hit's metadata.
36 */
37 public LCMetaData getMetaData() {
38 return metaData;
39 }
40
41 /**
42 * Set the metadata associated with this hit.
43 */
44 public void setMetaData(LCMetaData meta) {
45
46 this.metaData = meta;
47 }
48
49 /**
50 * Get the subdetector of this hit.
51 * @return The Subdetector of this hit.
52 */
53 public Subdetector getSubdetector() {
54 return getIDDecoder().getSubdetector();
55 }
56
57 /**
58 * Get the {@see org.lcsim.detector.IDetectorElement} associated with this hit.
59 * @return The IDetectorElement for this hit.
60 */
61 public IDetectorElement getDetectorElement() {
62 if (detectorElement == null) {
63 // Attempt to lookup the geometry using this exact ID.
64 detectorElement = findDetectorElement(getIdentifier());
65 if (detectorElement == null) {
66 // Presumably if the ID lookup fails, this means it has non-geometric fields,
67 // so use the global position instead.
68 if (getPositionVec() != null) {
69 detectorElement = findDetectorElement(getPositionVec());
70 }
71 // Just leave it as null!
72 }
73 }
74 return detectorElement;
75 }
76
77 /**
78 * Set the @see org.lcsim.detector.IDetectorElement of this hit. By default, this will not override an
79 * existing value.
80 */
81 public void setDetectorElement(IDetectorElement de) {
82 this.detectorElement = de;
83 }
84
85 /**
86 * Get the {@see org.lcsim.detector.identifier.IExpandedIdentifier} of this hit.
87 * @return The expanded identifier of this hit.
88 */
89 public IExpandedIdentifier getExpandedIdentifier() {
90 if (expandedID == null) {
91 expandedID = getIdentifierHelper().unpack(getIdentifier());
92 }
93 return expandedID;
94 }
95
96 /**
97 * Get the identifier of this hit.
98 * @return The identifier of this hit.
99 */
100 public IIdentifier getIdentifier() {
101 return packedID;
102 }
103
104 /**
105 * Get the identifier helper of this hit.
106 * @return The hit's identifier helper.
107 */
108 public IIdentifierHelper getIdentifierHelper() {
109 return getSubdetector().getDetectorElement().getIdentifierHelper();
110 }
111
112 /**
113 * Get the detector identifier helper of this hit.
114 * @return The hit's detector identifier helper.
115 */
116 public DetectorIdentifierHelper getDetectorIdentifierHelper() {
117 return (DetectorIdentifierHelper)getIdentifierHelper();
118 }
119
120 /**
121 * Get the {@see org.lcsim.geometryIDDecoder} of this hit.
122 * @return The hit's id decoder.
123 */
124 public IDDecoder getIDDecoder() {
125 return metaData.getIDDecoder();
126 }
127
128 /**
129 * Get the layer number of this hit.
130 * @return The layer number of this hit.
131 */
132 public int getLayerNumber() {
133 return getIdentifierHelper().getValue(getIdentifier(), "layer");
134 }
135
136 /**
137 * Get the barrel flag of this hit.
138 * @return The barrel flag of this hit.
139 */
140 public BarrelEndcapFlag getBarrelEndcapFlag() {
141 return BarrelEndcapFlag.createBarrelEndcapFlag(getIdentifierHelper().getValue(getIdentifier(), "barrel"));
142 }
143
144 /**
145 * Get the system id of this hit.
146 * @return The system id of this hit.
147 */
148 public int getSystemId() {
149 return getIdentifierHelper().getValue(getIdentifier(), "system");
150 }
151
152 /**
153 * Get a field value from the hit's identifier.
154 * @return The field value from the hit's identifier.
155 */
156 public int getIdentifierFieldValue(String field) {
157 return getIdentifierHelper().getValue(getIdentifier(), field);
158 }
159
160 /**
161 * Get the position of the hit. This may be different than the position of the hit's DetectorElement.
162 * @return The position of this hit as a double array of size 3.
163 */
164 public double[] getPosition() {
165 if (positionVec == null) {
166 calculatePosition();
167 }
168 return positionVec.v();
169 }
170
171 /**
172 * Get the position of this hit in mm as a {@see hep.physics.vec.Hep3Vector}.
173 * @return The position vector of the hit in mm.
174 */
175 public Hep3Vector getPositionVec() {
176 return positionVec;
177 }
178
179 /**
180 * Calculate the position of the hit, depending on what information is available on the object.
181 */
182 protected void calculatePosition() {
183 // Is the position not set already?
184 if (positionVec == null) {
185
186 // Is the detector object not set yet?
187 if (detectorElement == null) {
188 // Try to find a detector object to link to this hit.
189 detectorElement = findDetectorElement(getIdentifier());
190 }
191
192 // Does the hit ID match the DetectorElement exactly?
193 if (detectorElement != null && detectorElement.getIdentifier().equals(getIdentifier())) {
194 // Set the position from the DetectorElement.
195 this.positionVec = detectorElement.getGeometry().getPosition();
196 } else {
197 // This is what should happen for IDs with virtual segmentation values.
198 // The IDDecoder needs to be used here if it is set on the hit.
199 if (this.metaData != null) {
200 IDDecoder decoder = this.getIDDecoder();
201 if (decoder != null) {
202 decoder.setID(this.getIdentifier().getValue());
203 this.positionVec = new BasicHep3Vector(decoder.getPosition());
204 }
205 }
206 }
207 }
208 }
209
210 /**
211 * Find a DetectorElement by its identifier.
212 * @param id The identifier.
213 * @return The DetectorElement matching the identifier.
214 */
215 protected IDetectorElement findDetectorElement(IIdentifier id) {
216 IDetectorElement mommy = null;
217 if (this.metaData != null) {
218 // Use subdetector's volume as top.
219 mommy = this.getIDDecoder().getSubdetector().getDetectorElement();
220 }
221 if (mommy == null) {
222 // Use the world volume as top.
223 mommy = ((DetectorElement) DetectorElementStore.getInstance().get(0)).getTop();
224 }
225
226 // Find DetectorElements with exactly matching ID.
227 IDetectorElementContainer detectorElements = mommy.findDetectorElement(id);
228
229 // FIXME: Beware! The container itself can be null, which should be fixed (detector-framework).
230 if (detectorElements != null && detectorElements.size() == 1) {
231 return detectorElements.get(0);
232 } else {
233 return null;
234 }
235 }
236
237 /**
238 * Find a DetectorElement by its global Cartesian position.
239 * @param position The position.
240 * @return The DetectorElement at the position.
241 */
242 protected IDetectorElement findDetectorElement(Hep3Vector position) {
243 IDetectorElement mommy = null;
244 if (this.metaData != null) {
245 // Use subdetector's volume as top.
246 mommy = this.getIDDecoder().getSubdetector().getDetectorElement();
247 }
248 if (mommy == null) {
249 // Use the world volume.
250 mommy = ((DetectorElement) DetectorElementStore.getInstance().get(0)).getTop().findDetectorElement(getPositionVec());
251 }
252 return mommy.findDetectorElement(this.positionVec);
253 }
254 }