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1 package net.sf.saxon.expr;
2
3 import net.sf.saxon.om.Item;
4 import net.sf.saxon.om.Name;
5 import net.sf.saxon.om.NamePool;
6 import net.sf.saxon.om.QNameException;
7 import net.sf.saxon.style.StandardNames;
8 import net.sf.saxon.trans.StaticError;
9 import net.sf.saxon.trans.XPathException;
10 import net.sf.saxon.type.AtomicType;
11 import net.sf.saxon.type.ItemType;
12 import net.sf.saxon.type.Type;
13 import net.sf.saxon.value.*;
14
15 import java.io.PrintStream  ;
16 import java.util.Iterator ;
17
18
21
22 public class CastAsQName extends ComputedExpression {
23
24 private Expression operand;
25 private AtomicType targetType;
26
27 public CastAsQName(Expression s, AtomicType target) {
28 operand = s;
29 targetType = target;
30 }
31
32 public Expression analyze(StaticContext env, ItemType contextItemType) throws XPathException {
33 if (operand instanceof StringValue) {
34 try {
35 CharSequence arg = ((StringValue)operand).getStringValueCS();
36 String parts[] = Name.getQNameParts(arg);
37 String uri;
38 if ("".equals(parts[0])) {
39 uri = "";
40 } else {
41 uri = env.getURIForPrefix(parts[0]);
42 if (uri==null) {
43 StaticError e = new StaticError("Prefix '" + parts[0] + "' has not been declared");
44 throw e;
45 }
46 }
47 if (targetType.getFingerprint() == StandardNames.XS_QNAME) {
48 return new QNameValue(parts[0], uri, parts[1]);
49 } else if (Type.isSubType(targetType, Type.QNAME_TYPE)) {
50 QNameValue q = new QNameValue(parts[0], uri, parts[1]);
51 AtomicValue av = targetType.makeDerivedValue(q, arg, true);
52 if (av instanceof ValidationErrorValue) {
53 throw ((ValidationErrorValue)av).getException();
54 }
55 return av;
56 } else {
57 NotationValue n = new NotationValue(parts[0], uri, parts[1]);
58 AtomicValue av = targetType.makeDerivedValue(n, arg, true);
59 if (av instanceof ValidationErrorValue) {
60 throw ((ValidationErrorValue)av).getException();
61 }
62 return av;
63 }
64 } catch (QNameException err) {
65 StaticError e = new StaticError(err);
66 throw e;
67 }
68 } else {
69 StaticError err = new StaticError("The argument of a QName constructor must be a string literal");
70 throw err;
71 }
72 }
73
74 public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException {
75 if (operand instanceof StringValue) {
76 try {
77 CharSequence arg = ((StringValue)operand).getStringValueCS();
78 String parts[] = Name.getQNameParts(arg);
79 String uri;
80 if ("".equals(parts[0])) {
81 uri = "";
82 } else {
83 uri = env.getURIForPrefix(parts[0]);
84 if (uri==null) {
85 StaticError e = new StaticError("Prefix '" + parts[0] + "' has not been declared");
86 throw e;
87 }
88 }
89 if (targetType.getFingerprint() == StandardNames.XS_QNAME) {
90 return new QNameValue(parts[0], uri, parts[1]);
91 } else if (Type.isSubType(targetType, Type.QNAME_TYPE)) {
92 QNameValue q = new QNameValue(parts[0], uri, parts[1]);
93 AtomicValue av = targetType.makeDerivedValue(q, arg, true);
94 if (av instanceof ValidationErrorValue) {
95 throw ((ValidationErrorValue)av).getException();
96 }
97 return av;
98 } else {
99 NotationValue n = new NotationValue(parts[0], uri, parts[1]);
100 AtomicValue av = targetType.makeDerivedValue(n, arg, true);
101 if (av instanceof ValidationErrorValue) {
102 throw ((ValidationErrorValue)av).getException();
103 }
104 return av;
105 }
106 } catch (QNameException err) {
107 StaticError e = new StaticError(err);
108 throw e;
109 }
110 } else {
111 StaticError err = new StaticError("The argument of a QName constructor must be a string literal");
112 throw err;
113 }
114 }
115
116
133
134 public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException {
135 operand = operand.optimize(opt, env, contextItemType);
136 if (operand instanceof Value) {
137 return Value.asValue(evaluateItem(null));
138 }
139 return this;
140 }
141
142 public Expression promote(PromotionOffer offer) throws XPathException {
143 return super.promote(offer);
144 }
145
146 public int computeCardinality() {
147 return StaticProperty.EXACTLY_ONE;
148 }
149
150 public ItemType getItemType() {
151 return targetType;
152 }
153
154
158
159 public int computeSpecialProperties() {
160 int p = super.computeSpecialProperties();
161 return p | StaticProperty.NON_CREATIVE;
162 }
163
164 public int getIntrinsicDependencies() {
165 return 0;
166 }
167
168 public Iterator iterateSubExpressions() {
169 return new MonoIterator(operand);
170 }
171
172 public Item evaluateItem(XPathContext context) throws XPathException {
173 throw new UnsupportedOperationException ("A QName constructor cannot be evaluated at run-time");
174 }
175
176 public void display(int level, NamePool pool, PrintStream out) {
177 out.println(ExpressionTool.indent(level) + "cast as QName");
178 operand.display(level+1, pool, out);
179 }
180 }
181 |
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