/**
* @param context
* @param variable
* @return The evaluated value of the variable.
* @throws MethodInvocationException
*/
public Object getVariableValue(Context context, String variable)
throws MethodInvocationException {
Object obj = null;
try {
obj = context.get(variable);
} catch (RuntimeException e) {
log.error(
"Exception calling reference $" + variable + " at " + Log.formatFileString(uberInfo));
throw e;
}
if (strictRef && obj == null) {
if (!context.containsKey(variable)) {
log.error(
"Variable $" + variable + " has not been set at " + Log.formatFileString(uberInfo));
throw new MethodInvocationException(
"Variable $" + variable + " has not been set",
null,
identifier,
uberInfo.getTemplateName(),
uberInfo.getLine(),
uberInfo.getColumn());
}
}
return obj;
}
/**
* Computes boolean value of this reference Returns the actual value of reference return type
* boolean, and 'true' if value is not null
*
* @param context context to compute value with
* @return True if evaluation was ok.
* @throws MethodInvocationException
*/
public boolean evaluate(InternalContextAdapter context) throws MethodInvocationException {
Object value = execute(null, context);
if (value == null) {
return false;
} else if (value instanceof Boolean) {
if (((Boolean) value).booleanValue()) return true;
else return false;
} else if (toStringNullCheck) {
try {
return value.toString() != null;
} catch (Exception e) {
throw new VelocityException(
"Reference evaluation threw an exception at " + Log.formatFileString(this), e);
}
} else {
return true;
}
}
/**
* Sets the value of a complex reference (something like $foo.bar) Currently used by
* ASTSetReference()
*
* @see ASTSetDirective
* @param context context object containing this reference
* @param value Object to set as value
* @return true if successful, false otherwise
* @throws MethodInvocationException
*/
public boolean setValue(InternalContextAdapter context, Object value)
throws MethodInvocationException {
if (jjtGetNumChildren() == 0) {
context.put(rootString, value);
return true;
}
/*
* The rootOfIntrospection is the object we will
* retrieve from the Context. This is the base
* object we will apply reflection to.
*/
Object result = getVariableValue(context, rootString);
if (result == null) {
String msg = "reference set is not a valid reference at " + Log.formatFileString(uberInfo);
log.error(msg);
return false;
}
/*
* How many child nodes do we have?
*/
for (int i = 0; i < numChildren - 1; i++) {
result = jjtGetChild(i).execute(result, context);
if (result == null) {
if (strictRef) {
String name = jjtGetChild(i + 1).getFirstToken().image;
throw new MethodInvocationException(
"Attempted to access '" + name + "' on a null value",
null,
name,
uberInfo.getTemplateName(),
jjtGetChild(i + 1).getLine(),
jjtGetChild(i + 1).getColumn());
}
String msg = "reference set is not a valid reference at " + Log.formatFileString(uberInfo);
log.error(msg);
return false;
}
}
if (astIndex != null) {
// If astIndex is not null then we are actually setting an index reference,
// something of the form $foo[1] =, or in general any reference that ends with
// the brackets. This means that we need to call a more general method
// of the form set(Integer, <something>), or put(Object, <something), where
// the first parameter is the index value and the second is the LHS of the set.
Object argument = astIndex.jjtGetChild(0).value(context);
// If negative, turn -1 into (size - 1)
argument = ASTIndex.adjMinusIndexArg(argument, result, context, astIndex);
Object[] params = {argument, value};
Class[] paramClasses = {
params[0] == null ? null : params[0].getClass(),
params[1] == null ? null : params[1].getClass()
};
String methodName = "set";
VelMethod method =
ClassUtils.getMethod(methodName, params, paramClasses, result, context, astIndex, false);
if (method == null) {
// If we can't find a 'set' method, lets try 'put', This warrents a little
// investigation performance wise... if the user is using the hash
// form $foo["blaa"], then it may be expensive to first try and fail on 'set'
// then go to 'put'? The problem is that getMethod will try the cache, then
// perform introspection on 'result' for 'set'
methodName = "put";
method =
ClassUtils.getMethod(
methodName, params, paramClasses, result, context, astIndex, false);
}
if (method == null) {
// couldn't find set or put method, so bail
if (strictRef) {
throw new VelocityException(
"Found neither a 'set' or 'put' method with param types '("
+ printClass(paramClasses[0])
+ ","
+ printClass(paramClasses[1])
+ ")' on class '"
+ result.getClass().getName()
+ "' at "
+ Log.formatFileString(astIndex));
}
return false;
}
try {
method.invoke(result, params);
} catch (RuntimeException e) {
// Kludge since invoke throws Exception, pass up Runtimes
throw e;
} catch (Exception e) {
throw new MethodInvocationException(
"Exception calling method '"
+ methodName
+ "("
+ printClass(paramClasses[0])
+ ","
+ printClass(paramClasses[1])
+ ")' in "
+ result.getClass(),
e.getCause(),
identifier,
astIndex.getTemplateName(),
astIndex.getLine(),
astIndex.getColumn());
}
return true;
}
/*
* We support two ways of setting the value in a #set($ref.foo = $value ) :
* 1) ref.setFoo( value )
* 2) ref,put("foo", value ) to parallel the get() map introspection
*/
try {
VelPropertySet vs = rsvc.getUberspect().getPropertySet(result, identifier, value, uberInfo);
if (vs == null) {
if (strictRef) {
throw new MethodInvocationException(
"Object '"
+ result.getClass().getName()
+ "' does not contain property '"
+ identifier
+ "'",
null,
identifier,
uberInfo.getTemplateName(),
uberInfo.getLine(),
uberInfo.getColumn());
} else {
return false;
}
}
vs.invoke(result, value);
} catch (InvocationTargetException ite) {
/*
* this is possible
*/
throw new MethodInvocationException(
"ASTReference : Invocation of method '"
+ identifier
+ "' in "
+ result.getClass()
+ " threw exception "
+ ite.getTargetException().toString(),
ite.getTargetException(),
identifier,
getTemplateName(),
this.getLine(),
this.getColumn());
}
/** pass through application level runtime exceptions */
catch (RuntimeException e) {
throw e;
} catch (Exception e) {
/*
* maybe a security exception?
*/
String msg =
"ASTReference setValue() : exception : "
+ e
+ " template at "
+ Log.formatFileString(uberInfo);
log.error(msg, e);
throw new VelocityException(msg, e);
}
return true;
}
/**
* 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);
return result;
}
/*
* 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;
}
}