@Override
public Object convert(
Object existingDestinationFieldValue,
Object sourceFieldValue,
Class<?> destinationClass,
Class<?> sourceClass) {
try {
if (currentExchange.get() == null) {
throw new IllegalStateException("Current exchange has not been set for ExpressionMapper");
}
Expression exp;
// Resolve the language being used for this expression and evaluate
Exchange exchange = currentExchange.get();
Language expLang = exchange.getContext().resolveLanguage(getLanguagePart());
String scheme = getSchemePart();
if (scheme != null
&& (scheme.equalsIgnoreCase("classpath")
|| scheme.equalsIgnoreCase("file")
|| scheme.equalsIgnoreCase("http"))) {
String path = getPathPart();
try {
exp = expLang.createExpression(resolveScript(scheme + ":" + path));
} catch (IOException e) {
throw new IllegalStateException("Expression script specified but not found", e);
}
} else {
exp = expLang.createExpression(getExpressionPart());
}
return exp.evaluate(exchange, destinationClass);
} finally {
done();
}
}
private Expression createFileLanguageExpression(String expression) {
Language language;
// only use file language if the name is complex (eg. using $)
if (expression.contains("$")) {
language = getCamelContext().resolveLanguage("file");
} else {
language = getCamelContext().resolveLanguage("constant");
}
return language.createExpression(expression);
}
/**
* Asserts that the given language name and expression evaluates to the given value on a specific
* exchange
*/
protected void assertExpression(
Exchange exchange, String languageName, String expressionText, Object expectedValue) {
Language language = assertResolveLanguage(languageName);
Expression expression = language.createExpression(expressionText);
assertNotNull(
"No Expression could be created for text: " + expressionText + " language: " + language,
expression);
assertExpression(expression, exchange, expectedValue);
}