Examples with ToStringEvaluator org.apache.nifi.attribute.expression.language.evaluation.functions.ToStringEvaluator used on opensource projects

Example 1 with ToStringEvaluator

use of org.apache.nifi.attribute.expression.language.evaluation.functions.ToStringEvaluator in project nifi by apache.

the class ExpressionCompiler method newStringLiteralEvaluator.

private Evaluator<String> newStringLiteralEvaluator(final String literalValue) {
    if (literalValue == null || literalValue.length() < 2) {
        return addToken(new StringLiteralEvaluator(literalValue), literalValue);
    }
    final List<Range> ranges = Query.extractExpressionRanges(literalValue);
    if (ranges.isEmpty()) {
        return addToken(new StringLiteralEvaluator(literalValue), literalValue);
    }
    final List<Evaluator<?>> evaluators = new ArrayList<>();
    int lastIndex = 0;
    for (final Range range : ranges) {
        if (range.getStart() > lastIndex) {
            evaluators.add(newStringLiteralEvaluator(literalValue.substring(lastIndex, range.getStart())));
        }
        final String treeText = literalValue.substring(range.getStart(), range.getEnd() + 1);
        evaluators.add(buildEvaluator(compileTree(treeText)));
        lastIndex = range.getEnd() + 1;
    }
    final Range lastRange = ranges.get(ranges.size() - 1);
    if (lastRange.getEnd() + 1 < literalValue.length()) {
        final String treeText = literalValue.substring(lastRange.getEnd() + 1);
        evaluators.add(newStringLiteralEvaluator(treeText));
    }
    if (evaluators.size() == 1) {
        return toStringEvaluator(evaluators.get(0));
    }
    Evaluator<String> lastEvaluator = toStringEvaluator(evaluators.get(0));
    for (int i = 1; i < evaluators.size(); i++) {
        lastEvaluator = new AppendEvaluator(lastEvaluator, toStringEvaluator(evaluators.get(i)));
    }
    this.evaluators.addAll(evaluators);
    return lastEvaluator;
}