From bee5dd259a4438d45ecd1bcc26dfba12875236d6 Mon Sep 17 00:00:00 2001
From: Thomas Lenz <thomas.lenz@egiz.gv.at>
Date: Tue, 26 Jun 2018 11:03:48 +0200
Subject: initial commit

---
 .../process/spring/SpringExpressionEvaluator.java  | 63 ++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/spring/SpringExpressionEvaluator.java

(limited to 'eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/spring/SpringExpressionEvaluator.java')

diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/spring/SpringExpressionEvaluator.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/spring/SpringExpressionEvaluator.java
new file mode 100644
index 00000000..d301b77e
--- /dev/null
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/spring/SpringExpressionEvaluator.java
@@ -0,0 +1,63 @@
+/*******************************************************************************
+ *******************************************************************************/
+package at.gv.egiz.eaaf.core.impl.idp.process.spring;
+
+import java.util.Objects;
+
+import javax.annotation.PostConstruct;
+
+import org.apache.commons.lang3.BooleanUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.expression.BeanFactoryResolver;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ExpressionParser;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
+
+import at.gv.egiz.eaaf.core.api.idp.process.ExpressionEvaluationContext;
+import at.gv.egiz.eaaf.core.api.idp.process.ExpressionEvaluator;
+import at.gv.egiz.eaaf.core.impl.idp.process.model.Transition;
+
+/**
+ * Expression evaluator for processing {@link Transition} conditions allowing to reference Spring beans from the
+ * application context.
+ * 
+ * @author tknall
+ * 
+ */
+public class SpringExpressionEvaluator implements ExpressionEvaluator {
+
+	private Logger log = LoggerFactory.getLogger(getClass());
+	private ExpressionParser parser = new SpelExpressionParser();
+	private StandardEvaluationContext evaluationContext = new StandardEvaluationContext();
+
+	@Autowired(required = false)
+	private ApplicationContext ctx;
+
+	@PostConstruct
+	private void init() {
+		if (ctx != null) {
+			evaluationContext.setBeanResolver(new BeanFactoryResolver(ctx));
+		}
+	}
+
+	@Override
+	public boolean evaluate(ExpressionEvaluationContext expressionContext, String expression) {
+		Objects.requireNonNull(expression, "Expression must not be null.");
+		log.trace("Evaluating '{}'.", expression);
+
+		Expression expr = parser.parseExpression(expression);
+		Boolean result = expr.getValue(evaluationContext, expressionContext, Boolean.class);
+		if (result == null) {
+			log.warn("Evaluation of '{}' results in null-value.", expression);
+		} else {
+			log.debug("Expression '{}' -> {}", expression, result);
+		}
+
+		return BooleanUtils.isTrue(result);
+	}
+
+}
-- 
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