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1
16 package scriptella.expression;
17
18 import org.apache.commons.jexl.ExpressionFactory;
19 import org.apache.commons.jexl.JexlContext;
20 import org.apache.commons.jexl.parser.TokenMgrError;
21 import scriptella.spi.ParametersCallback;
22
23 import java.util.Collection  ;
24 import java.util.Map ;
25 import java.util.Set ;
26
27
28
34 public class JexlExpression extends Expression {
35 private JexlContextAdapter adapter = new JexlContextAdapter();
36 private org.apache.commons.jexl.Expression expression;
37
38 protected JexlExpression(String expression) throws ParseException {
39 super(expression);
40
41 try {
42 this.expression = ExpressionFactory.createExpression(expression);
43 } catch (Exception e) {
44 throw new ParseException(e.getMessage(),e);
45 } catch (TokenMgrError e) {
46 throw new ParseException(e.getMessage(),e);
47 }
48 }
49
50 public Object evaluate(final ParametersCallback callback)
51 throws EvaluationException {
52 try {
53 adapter.setContext(callback);
54
55 return expression.evaluate(adapter);
56 } catch (Exception e) {
57 throw new EvaluationException(e);
58 } finally {
59 adapter.unsetContext();
60 }
61 }
62
63
66 private static class JexlContextAdapter implements JexlContext {
67 private ParametersCallbackMap map = new ParametersCallbackMap();
68
69 public void setVars(final Map map) {
70 }
71
72 public Map getVars() {
73 return map;
74 }
75
76 public void setContext(final ParametersCallback parametersCallback) {
77 map.callback = parametersCallback;
78 }
79
80 public void unsetContext() {
81 map.callback = null;
82 }
83 }
84
85
90 private static final class ParametersCallbackMap implements Map {
91 private ParametersCallback callback;
92
93 public int size() {
94 throw new UnsupportedOperationException ();
95 }
96
97 public boolean isEmpty() {
98 throw new UnsupportedOperationException ();
99 }
100
101 public boolean containsKey(final Object key) {
102 throw new UnsupportedOperationException ();
103 }
104
105 public boolean containsValue(final Object value) {
106 throw new UnsupportedOperationException ();
107 }
108
109 public Object get(final Object key) {
110 return callback.getParameter((String ) key);
111 }
112
113 public Object put(final Object key, final Object o1) {
114 throw new UnsupportedOperationException ();
115 }
116
117 public Object remove(final Object key) {
118 throw new UnsupportedOperationException ();
119 }
120
121 public void putAll(final Map map) {
122 throw new UnsupportedOperationException ();
123 }
124
125 public void clear() {
126 throw new UnsupportedOperationException ();
127 }
128
129 public Set keySet() {
130 throw new UnsupportedOperationException ();
131 }
132
133 public Collection values() {
134 throw new UnsupportedOperationException ();
135 }
136
137 public Set <Entry<String , Object >> entrySet() {
138 throw new UnsupportedOperationException ();
139 }
140 }
141 }
142 |
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