/**
* gets the value of the reference and outputs it to the writer.
*
* @param context context of data to use in getting value
* @param writer writer to render to
* @return True if rendering was successful.
* @throws IOException
* @throws MethodInvocationException
*/
public boolean render(InternalContextAdapter context, Writer writer)
throws IOException, MethodInvocationException {
if (referenceType == RUNT) {
writer.write(rootString);
return true;
}
Object value = null;
if (escaped && strictEscape) {
/**
* If we are in strict mode and the variable is escaped, then don't bother to retreive the
* value since we won't use it. And if the var is not defined it will throw an exception. Set
* value to TRUE to fall through below with simply printing $foo, and not \$foo
*/
value = Boolean.TRUE;
} else {
value = execute(null, context);
}
String localNullString = null;
/*
* if this reference is escaped (\$foo) then we want to do one of two things : 1) if this is
* a reference in the context, then we want to print $foo 2) if not, then \$foo (its
* considered schmoo, not VTL)
*/
if (escaped) {
localNullString = getNullString(context);
if (value == null) {
writer.write(escPrefix);
writer.write("\\");
writer.write(localNullString);
} else {
writer.write(escPrefix);
writer.write(localNullString);
}
return true;
}
/*
* the normal processing
*
* if we have an event cartridge, get a new value object
*/
value = EventHandlerUtil.referenceInsert(rsvc, context, literal, value);
String toString = null;
if (value != null) {
if (value instanceof Renderable) {
Renderable renderable = (Renderable) value;
try {
if (renderable.render(context, writer)) return true;
} catch (RuntimeException e) {
// We commonly get here when an error occurs within a block reference.
// We want to log where the reference is at so that a developer can easily
// know where the offending call is located. This can be seen
// as another element of the error stack we report to log.
log.error(
"Exception rendering "
+ ((renderable instanceof Reference) ? "block " : "Renderable ")
+ rootString
+ " at "
+ Log.formatFileString(this));
throw e;
}
}
toString = value.toString();
}
if (value == null || toString == null) {
if (strictRef) {
if (referenceType != QUIET_REFERENCE) {
log.error(
"Prepend the reference with '$!' e.g., $!"
+ literal().substring(1)
+ " if you want Velocity to ignore the reference when it evaluates to null");
if (value == null) {
throw new VelocityException(
"Reference "
+ literal()
+ " evaluated to null when attempting to render at "
+ Log.formatFileString(this));
} else // toString == null
{
// This will probably rarely happen, but when it does we want to
// inform the user that toString == null so they don't pull there
// hair out wondering why Velocity thinks the value is null.
throw new VelocityException(
"Reference "
+ literal()
+ " evaluated to object "
+ value.getClass().getName()
+ " whose toString() method returned null at "
+ Log.formatFileString(this));
}
}
return true;
}
/*
* write prefix twice, because it's schmoo, so the \ don't escape each
* other...
*/
localNullString = getNullString(context);
if (!strictEscape) {
// If in strict escape mode then we only print escape once.
// Yea, I know.. brittle stuff
writer.write(escPrefix);
}
writer.write(escPrefix);
writer.write(morePrefix);
writer.write(localNullString);
if (logOnNull && referenceType != QUIET_REFERENCE && log.isDebugEnabled()) {
log.debug(
"Null reference [template '"
+ getTemplateName()
+ "', line "
+ this.getLine()
+ ", column "
+ this.getColumn()
+ "] : "
+ this.literal()
+ " cannot be resolved.");
}
return true;
} else {
/*
* non-null processing
*/
writer.write(escPrefix);
writer.write(morePrefix);
writer.write(toString);
return true;
}
}
/**
* gets an Object that 'is' the value of the reference
*
* @param o unused Object parameter
* @param context context used to generate value
* @return The execution result.
* @throws MethodInvocationException
*/
public Object execute(Object o, InternalContextAdapter context) throws MethodInvocationException {
if (referenceType == RUNT) return null;
/*
* get the root object from the context
*/
Object result = getVariableValue(context, rootString);
if (result == null && !strictRef) {
return EventHandlerUtil.invalidGetMethod(
rsvc, context, getDollarBang() + rootString, null, null, uberInfo);
}
/*
* Iteratively work 'down' (it's flat...) the reference
* to get the value, but check to make sure that
* every result along the path is valid. For example:
*
* $hashtable.Customer.Name
*
* The $hashtable may be valid, but there is no key
* 'Customer' in the hashtable so we want to stop
* when we find a null value and return the null
* so the error gets logged.
*/
try {
Object previousResult = result;
int failedChild = -1;
for (int i = 0; i < numChildren; i++) {
if (strictRef && result == null) {
/**
* At this point we know that an attempt is about to be made to call a method or property
* on a null value.
*/
String name = jjtGetChild(i).getFirstToken().image;
throw new VelocityException(
"Attempted to access '"
+ name
+ "' on a null value at "
+ Log.formatFileString(
uberInfo.getTemplateName(),
+jjtGetChild(i).getLine(),
jjtGetChild(i).getColumn()));
}
previousResult = result;
result = jjtGetChild(i).execute(result, context);
if (result == null && !strictRef) // If strict and null then well catch this
// next time through the loop
{
failedChild = i;
break;
}
}
if (result == null) {
if (failedChild == -1) {
result =
EventHandlerUtil.invalidGetMethod(
rsvc, context, getDollarBang() + rootString, previousResult, null, uberInfo);
} else {
StringBuffer name = new StringBuffer(getDollarBang()).append(rootString);
for (int i = 0; i <= failedChild; i++) {
Node node = jjtGetChild(i);
if (node instanceof ASTMethod) {
name.append(".").append(((ASTMethod) node).getMethodName()).append("()");
} else {
name.append(".").append(node.getFirstToken().image);
}
}
if (jjtGetChild(failedChild) instanceof ASTMethod) {
String methodName = ((ASTMethod) jjtGetChild(failedChild)).getMethodName();
result =
EventHandlerUtil.invalidMethod(
rsvc, context, name.toString(), previousResult, methodName, uberInfo);
} else {
String property = jjtGetChild(failedChild).getFirstToken().image;
result =
EventHandlerUtil.invalidGetMethod(
rsvc, context, name.toString(), previousResult, property, uberInfo);
}
}
}
return result;
} catch (MethodInvocationException mie) {
mie.setReferenceName(rootString);
throw mie;
}
}
