package org.apache.lucene.expressions;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.DoubleValues;
import org.apache.lucene.search.DoubleValuesSource;
final class CachingExpressionValueSource extends ExpressionValueSource {
CachingExpressionValueSource(Bindings bindings, Expression expression) {
super(bindings, expression);
}
CachingExpressionValueSource(DoubleValuesSource[] variables, Expression expression, boolean needsScores) {
super(variables, expression, needsScores);
}
public CachingExpressionValueSource(ExpressionValueSource expressionValueSource) {
super(expressionValueSource.variables, expressionValueSource.expression, expressionValueSource.needsScores);
}
@Override
public DoubleValues getValues(LeafReaderContext readerContext, DoubleValues scores) throws IOException {
return getValuesWithCache(readerContext, scores, new HashMap<>());
}
private DoubleValues getValuesWithCache(LeafReaderContext readerContext, DoubleValues scores,
Map<String, DoubleValues> valuesCache) throws IOException {
DoubleValues[] externalValues = new DoubleValues[expression.variables.length];
for (int i = 0; i < variables.length; ++i) {
String externalName = expression.variables[i];
DoubleValues values = valuesCache.get(externalName);
if (values == null) {
if (variables[i] instanceof CachingExpressionValueSource) {
values = ((CachingExpressionValueSource) variables[i]).getValuesWithCache(readerContext, scores, valuesCache);
} else {
values = variables[i].getValues(readerContext, scores);
}
if (values == null) {
throw new RuntimeException("Unrecognized variable (" + externalName + ") referenced in expression (" +
expression.sourceText + ").");
}
valuesCache.put(externalName, values);
}
externalValues[i] = zeroWhenUnpositioned(values);
}
return new ExpressionFunctionValues(expression, externalValues);
}
}