if (walker.getStatementSpec().getStreamSpecs().size() > 1) {
throw new IllegalStateException("Unexpected multiple stream specifications encountered");
}
// Get pattern specification
PatternStreamSpecRaw patternStreamSpec = (PatternStreamSpecRaw) walker.getStatementSpec().getStreamSpecs().get(0);
// Create statement spec, set pattern stream, set wildcard select
StatementSpecRaw statementSpec = new StatementSpecRaw(SelectClauseStreamSelectorEnum.ISTREAM_ONLY);
statementSpec.getStreamSpecs().add(patternStreamSpec);
statementSpec.getSelectClauseSpec().getSelectExprList().clear();