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14 package ch.qos.logback.core.model.processor.conditional;
15
16 import ch.qos.logback.core.util.EnvUtil;
17 import ch.qos.logback.core.util.OptionHelper;
18 import ch.qos.logback.core.Context;
19 import ch.qos.logback.core.CoreConstants;
20 import ch.qos.logback.core.joran.conditional.Condition;
21 import ch.qos.logback.core.joran.conditional.PropertyEvalScriptBuilder;
22 import ch.qos.logback.core.model.Model;
23 import ch.qos.logback.core.model.conditional.IfModel;
24 import ch.qos.logback.core.model.conditional.IfModel.BranchState;
25 import ch.qos.logback.core.model.processor.ModelHandlerBase;
26 import ch.qos.logback.core.model.processor.ModelHandlerException;
27 import ch.qos.logback.core.model.processor.ModelInterpretationContext;
28 import ch.qos.logback.core.spi.ScanException;
29
30 public class IfModelHandler extends ModelHandlerBase {
31
32
33 public static final String MISSING_JANINO_MSG = "Could not find Janino library on the class path. Skipping conditional processing.";
34 public static final String MISSING_JANINO_SEE = "See also " + CoreConstants.CODES_URL + "#ifJanino";
35
36 enum Branch {IF_BRANCH, ELSE_BRANCH; }
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38 IfModel ifModel = null;
39
40 public IfModelHandler(Context context) {
41 super(context);
42 }
43
44 static public ModelHandlerBase makeInstance(Context context, ModelInterpretationContext ic) {
45 return new IfModelHandler(context);
46 }
47
48 @Override
49 protected Class<IfModel> getSupportedModelClass() {
50 return IfModel.class;
51 }
52
53 @Override
54 public void handle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
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56 ifModel = (IfModel) model;
57
58 if (!EnvUtil.isJaninoAvailable()) {
59 addError(MISSING_JANINO_MSG);
60 addError(MISSING_JANINO_SEE);
61 return;
62 }
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64 mic.pushModel(ifModel);
65 Condition condition = null;
66 int lineNum = model.getLineNumber();
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68 String conditionStr = ifModel.getCondition();
69 if (!OptionHelper.isNullOrEmptyOrAllSpaces(conditionStr)) {
70 try {
71 conditionStr = OptionHelper.substVars(conditionStr, mic, context);
72 } catch (ScanException e) {
73 addError("Failed to parse input [" + conditionStr + "] on line "+lineNum, e);
74 ifModel.setBranchState(BranchState.IN_ERROR);
75 return;
76 }
77
78 try {
79 PropertyEvalScriptBuilder pesb = new PropertyEvalScriptBuilder(mic);
80 pesb.setContext(context);
81 condition = pesb.build(conditionStr);
82 } catch (Exception|NoClassDefFoundError e) {
83 ifModel.setBranchState(BranchState.IN_ERROR);
84 addError("Failed to parse condition [" + conditionStr + "] on line "+lineNum, e);
85 return;
86 }
87
88 if (condition != null) {
89 boolean boolResult = condition.evaluate();
90 addInfo("Condition ["+conditionStr+"] evaluated to "+boolResult+ " on line "+lineNum);
91 ifModel.setBranchState(boolResult);
92 } else {
93 addError("The condition variable is null. This should not occur.");
94 ifModel.setBranchState(BranchState.IN_ERROR);
95 return;
96 }
97 }
98 }
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101 @Override
102 public void postHandle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
103
104 if(mic.isModelStackEmpty()) {
105 addError("Unexpected unexpected empty model stack.");
106 return;
107 }
108
109 Object o = mic.peekModel();
110 if (o != ifModel) {
111 addWarn("The object [" + o + "] on the top the of the stack is not the expected [" + ifModel);
112 } else {
113 mic.popModel();
114 }
115 }
116
117 }