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1 package net.sf.saxon.style;
2 import net.sf.saxon.expr.Expression;
3 import net.sf.saxon.expr.ExpressionTool;
4 import net.sf.saxon.instruct.Choose;
5 import net.sf.saxon.instruct.Executable;
6 import net.sf.saxon.instruct.TraceWrapper;
7 import net.sf.saxon.om.AttributeCollection;
8 import net.sf.saxon.om.Axis;
9 import net.sf.saxon.om.AxisIterator;
10 import net.sf.saxon.om.NodeInfo;
11 import net.sf.saxon.trans.XPathException;
12 import net.sf.saxon.type.ItemType;
13 import net.sf.saxon.value.BooleanValue;
14 import net.sf.saxon.value.EmptySequence;
15
16
19
20 public class XSLChoose extends StyleElement {
21
22 private StyleElement otherwise;
23 private int numberOfWhens = 0;
24
25
29
30 public boolean isInstruction() {
31 return true;
32 }
33
34
39
40 protected ItemType getReturnedItemType() {
41 return getCommonChildItemType();
42 }
43
44 public void prepareAttributes() throws XPathException {
45 AttributeCollection atts = getAttributeList();
46 for (int a=0; a<atts.getLength(); a++) {
47 int nc = atts.getNameCode(a);
48 checkUnknownAttribute(nc);
49 }
50 }
51
52 public void validate() throws XPathException {
53 checkWithinTemplate();
54
55 AxisIterator kids = iterateAxis(Axis.CHILD);
56 while(true) {
57 NodeInfo curr = (NodeInfo)kids.next();
58 if (curr == null) {
59 break;
60 }
61 if (curr instanceof XSLWhen) {
62 if (otherwise!=null) {
63 compileError("xsl:otherwise must come last", "XTSE0010");
64 }
65 numberOfWhens++;
66 } else if (curr instanceof XSLOtherwise) {
67 if (otherwise!=null) {
68 compileError("Only one xsl:otherwise allowed in an xsl:choose", "XTSE0010");
69 } else {
70 otherwise = (StyleElement)curr;
71 }
72 } else {
73 compileError("Only xsl:when and xsl:otherwise are allowed here", "XTSE0010");
74 }
75 }
76
77 if (numberOfWhens==0) {
78 compileError("xsl:choose must contain at least one xsl:when", "XTSE0010");
79 }
80 }
81
82
85
86 public void markTailCalls() {
87 AxisIterator kids = iterateAxis(Axis.CHILD);
88 while(true) {
89 NodeInfo curr = (NodeInfo)kids.next();
90 if (curr == null) {
91 return;
92 }
93 if (curr instanceof StyleElement) {
94 ((StyleElement)curr).markTailCalls();
95 }
96 }
97 }
98
99
100 public Expression compile(Executable exec) throws XPathException {
101
102 int entries = numberOfWhens + (otherwise==null ? 0 : 1);
103 Expression[] conditions = new Expression[entries];
104 Expression[] actions = new Expression[entries];
105
106 int w = 0;
107 AxisIterator kids = iterateAxis(Axis.CHILD);
108 while(true) {
109 NodeInfo curr = (NodeInfo)kids.next();
110 if (curr == null) {
111 break;
112 }
113 if (curr instanceof XSLWhen) {
114 conditions[w] = ((XSLWhen)curr).getCondition();
115 Expression b = ((XSLWhen)curr).compileSequenceConstructor(
116 exec, curr.iterateAxis(Axis.CHILD), true);
117 if (b == null) {
118 b = EmptySequence.getInstance();
119 }
120 try {
121 b = b.simplify(((XSLWhen)curr).getStaticContext());
122 actions[w] = b;
123 } catch (XPathException e) {
124 compileError(e);
125 }
126
127 if (getConfiguration().getTraceListener() != null) {
128 TraceWrapper trace = makeTraceInstruction((XSLWhen)curr, actions[w]);
129 trace.setParentExpression((XSLWhen)curr);
130 actions[w] = trace;
131 }
132
133 if (conditions[w] instanceof BooleanValue) {
135 if (((BooleanValue)conditions[w]).getBooleanValue()) {
136 entries = w+1;
138 break;
139 } else {
140 w--;
142 entries--;
143 }
144 }
145 w++;
146 } else if (curr instanceof XSLOtherwise) {
147 conditions[w] = BooleanValue.TRUE;
148 Expression b = ((XSLOtherwise)curr).compileSequenceConstructor(
149 exec, curr.iterateAxis(Axis.CHILD), true);
150 if (b == null) {
151 b = EmptySequence.getInstance();
152 }
153 try {
154 b = b.simplify(((XSLOtherwise)curr).getStaticContext());
155 actions[w] = b;
156 } catch (XPathException e) {
157 compileError(e);
158 }
159 if (getConfiguration().getTraceListener() != null) {
160 TraceWrapper trace = makeTraceInstruction((XSLOtherwise)curr, actions[w]);
161 trace.setParentExpression((XSLOtherwise)curr);
162 actions[w] = trace;
163 }
164 w++;
165 } else {
166 new AssertionError  ("Expected xsl:when or xsl:otherwise");
167 }
168 }
169
170 if (conditions.length != entries) {
171 if (entries==0) {
173 return null; }
175 if (entries==1 && (conditions[0] instanceof BooleanValue)) {
176 if (((BooleanValue)conditions[0]).getBooleanValue()) {
177 return actions[0];
179 } else {
180 return null;
182 }
183 }
184 Expression[] conditions2 = new Expression[entries];
185 System.arraycopy(conditions, 0, conditions2, 0, entries);
186 Expression[] actions2 = new Expression[entries];
187 System.arraycopy(actions, 0, actions2, 0, entries);
188 conditions = conditions2;
189 actions = actions2;
190 }
191
192 Choose ch = new Choose(conditions, actions);
193 ExpressionTool.makeParentReferences(ch);
194 return ch;
195 }
196
197 }
198
199 |
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