/** Evaluate using classic parameter binding using the pre compute expression */
private Object evaluateParameterBinding(
Exchange exchange, Expression expression, int index, Class<?> parameterType) {
Object answer = null;
// use object first to avoid type conversion so we know if there is a value or not
Object result = expression.evaluate(exchange, Object.class);
if (result != null) {
try {
if (parameterType.isInstance(result)) {
// optimize if the value is already the same type
answer = result;
} else {
// we got a value now try to convert it to the expected type
answer =
exchange.getContext().getTypeConverter().mandatoryConvertTo(parameterType, result);
}
if (LOG.isTraceEnabled()) {
LOG.trace(
"Parameter #{} evaluated as: {} type: ",
new Object[] {index, answer, ObjectHelper.type(answer)});
}
} catch (NoTypeConversionAvailableException e) {
if (LOG.isDebugEnabled()) {
LOG.debug(
"Cannot convert from type: {} to type: {} for parameter #{}",
new Object[] {ObjectHelper.type(result), parameterType, index});
}
throw new ParameterBindingException(e, method, index, parameterType, result);
}
} else {
LOG.trace("Parameter #{} evaluated as null", index);
}
return answer;
}
/**
* Evaluate using parameter values where the values can be provided in the method name syntax.
*
* <p>This methods returns accordingly:
*
* <ul>
* <li><tt>null</tt> - if not a parameter value
* <li><tt>Void.TYPE</tt> - if an explicit null, forcing Camel to pass in <tt>null</tt> for
* that given parameter
* <li>a non <tt>null</tt> value - if the parameter was a parameter value, and to be used
* </ul>
*
* @since 2.9
*/
private Object evaluateParameterValue(
Exchange exchange, int index, Object parameterValue, Class<?> parameterType) {
Object answer = null;
// convert the parameter value to a String
String exp =
exchange
.getContext()
.getTypeConverter()
.convertTo(String.class, exchange, parameterValue);
if (exp != null) {
// check if its a valid parameter value
boolean valid = BeanHelper.isValidParameterValue(exp);
if (!valid) {
// it may be a parameter type instead, and if so, then we should return null,
// as this method is only for evaluating parameter values
Boolean isClass =
BeanHelper.isAssignableToExpectedType(
exchange.getContext().getClassResolver(), exp, parameterType);
// the method will return a non null value if exp is a class
if (isClass != null) {
return null;
}
}
// use simple language to evaluate the expression, as it may use the simple language to
// refer to message body, headers etc.
Expression expression = null;
try {
expression = exchange.getContext().resolveLanguage("simple").createExpression(exp);
parameterValue = expression.evaluate(exchange, Object.class);
// use "null" to indicate the expression returned a null value which is a valid response
// we need to honor
if (parameterValue == null) {
parameterValue = "null";
}
} catch (Exception e) {
throw new ExpressionEvaluationException(
expression,
"Cannot create/evaluate simple expression: "
+ exp
+ " to be bound to parameter at index: "
+ index
+ " on method: "
+ getMethod(),
exchange,
e);
}
// special for explicit null parameter values (as end users can explicit indicate they want
// null as parameter)
// see method javadoc for details
if ("null".equals(parameterValue)) {
return Void.TYPE;
}
// the parameter value may match the expected type, then we use it as-is
if (parameterType.isAssignableFrom(parameterValue.getClass())) {
valid = true;
} else {
// the parameter value was not already valid, but since the simple language have evaluated
// the expression
// which may change the parameterValue, so we have to check it again to see if its now
// valid
exp = exchange.getContext().getTypeConverter().tryConvertTo(String.class, parameterValue);
// String values from the simple language is always valid
if (!valid) {
// re validate if the parameter was not valid the first time (String values should be
// accepted)
valid = parameterValue instanceof String || BeanHelper.isValidParameterValue(exp);
}
}
if (valid) {
// we need to unquote String parameters, as the enclosing quotes is there to denote a
// parameter value
if (parameterValue instanceof String) {
parameterValue = StringHelper.removeLeadingAndEndingQuotes((String) parameterValue);
}
if (parameterValue != null) {
try {
// its a valid parameter value, so convert it to the expected type of the parameter
answer =
exchange
.getContext()
.getTypeConverter()
.mandatoryConvertTo(parameterType, exchange, parameterValue);
if (LOG.isTraceEnabled()) {
LOG.trace(
"Parameter #{} evaluated as: {} type: ",
new Object[] {index, answer, ObjectHelper.type(answer)});
}
} catch (Exception e) {
if (LOG.isDebugEnabled()) {
LOG.debug(
"Cannot convert from type: {} to type: {} for parameter #{}",
new Object[] {ObjectHelper.type(parameterValue), parameterType, index});
}
throw new ParameterBindingException(e, method, index, parameterType, parameterValue);
}
}
}
}
return answer;
}
