/**
* Returns the index of the first field in <code>rel</code> which comes from its <code>ordinal
* </code>th input.
*
* <p>For example, if rel joins T0(A,B,C) to T1(D,E), then countFields(0,rel) yields 0, and
* countFields(1,rel) yields 3.
*/
private int computeFieldOffset(RelNode rel, int ordinal) {
if (ordinal == 0) {
// short-circuit for the common case
return 0;
}
int fieldOffset = 0;
final List<RelNode> inputs = rel.getInputs();
for (int i = 0; i < ordinal; i++) {
RelNode input = inputs.get(i);
fieldOffset += input.getRowType().getFieldList().size();
}
return fieldOffset;
}
@Override
public ParseTree visitChildInternal(RelNode child, int ordinal) {
final Convention convention = child.getConvention();
if (!(child instanceof JavaRel)) {
throw Util.newInternal(
"Relational expression '"
+ child
+ "' has '"
+ convention
+ "' calling convention, so must implement interface "
+ JavaRel.class);
}
JavaRel javaRel = (JavaRel) child;
final ParseTree p = javaRel.implement(this);
if ((convention == CallingConvention.JAVA) && (p != null)) {
throw Util.newInternal(
"Relational expression '"
+ child
+ "' returned '"
+ p
+ " on implement, but should have "
+ "returned null, because it has JAVA calling-convention. "
+ "(Note that similar calling-conventions, such as "
+ "Iterator, must return a value.)");
}
return p;
}
private void bindDeferred(JavaFrame frame, final RelNode rel) {
final StatementList statementList = getStatementList();
if (frame.bind == null) {
// this relational expression has not bound itself, so we presume
// that we can call its implementSelf() method
if (!(rel instanceof JavaSelfRel)) {
throw Util.newInternal(
"In order to bind-deferred, a "
+ "relational expression must implement JavaSelfRel: "
+ rel);
}
final JavaSelfRel selfRel = (JavaSelfRel) rel;
LazyBind lazyBind =
new LazyBind(
newVariable(),
statementList,
getTypeFactory(),
rel.getRowType(),
new VariableInitializerThunk() {
public VariableInitializer getInitializer() {
return selfRel.implementSelf(JavaRelImplementor.this);
}
});
bind(rel, lazyBind);
} else if ((frame.bind instanceof LazyBind)
&& (((LazyBind) frame.bind).statementList != statementList)) {
// Frame is already bound, but to a variable declared in a different
// scope. Re-bind it.
final LazyBind lazyBind = (LazyBind) frame.bind;
lazyBind.statementList = statementList;
lazyBind.bound = false;
}
}
private JavaFrame findFrame() {
RelNode previous = rel;
while (true) {
JavaFrame frame = (JavaFrame) mapRel2Frame.get(previous);
if (frame.bind != null) {
tracer.log(
Level.FINE,
"Bind " + rel.toString() + " to " + previous.toString() + "(" + frame.bind + ")");
return frame;
}
// go deeper
List<RelNode> inputs = previous.getInputs();
assert (inputs.size() == 1) : "input is not bound";
previous = inputs.get(0);
}
}
/**
* Records the fact that instances of <code>rel</code> are available via <code>bind</code> (which
* may be eager or lazy).
*/
private void bind(RelNode rel, Bind bind) {
tracer.log(Level.FINE, "Bind " + rel.toString() + " to " + bind);
JavaFrame frame = (JavaFrame) mapRel2Frame.get(rel);
frame.bind = bind;
boolean stupid = SaffronProperties.instance().stupid.get();
if (stupid) {
// trigger the declaration of the variable, even though it
// may not be used
Util.discard(bind.getVariable());
}
}
/**
* Returns the variable which, in the generated program, will hold the current row of a given
* relational expression. This method is only applicable if the relational expression is the
* current one or an input; if it is an ancestor, there is no current value, and this method
* returns null.
*/
public Variable findInputVariable(RelNode rel) {
while (true) {
JavaFrame frame = (JavaFrame) mapRel2Frame.get(rel);
if ((frame != null) && frame.hasVariable()) {
return frame.getVariable();
}
List<RelNode> inputs = rel.getInputs();
if (inputs.size() == 1) {
rel = inputs.get(0);
} else {
return null;
}
}
}
/**
* Declares a variable, and binds it lazily, so it only gets initialized if it is actually used.
*
* @return the Variable so declared
*/
public Variable bind(
RelNode rel, StatementList statementList, final VariableInitializer initializer) {
VariableInitializerThunk thunk =
new VariableInitializerThunk() {
public VariableInitializer getInitializer() {
return initializer;
}
};
Variable variable = newVariable();
LazyBind bind =
new LazyBind(variable, statementList, getTypeFactory(), rel.getRowType(), thunk);
bind(rel, bind);
return bind.getVariable();
}