imply-cheddar commented on a change in pull request #12241:
URL: https://github.com/apache/druid/pull/12241#discussion_r802315644
##########
File path:
sql/src/main/java/org/apache/druid/sql/calcite/expression/DruidExpression.java
##########
@@ -32,127 +32,303 @@
import org.apache.druid.segment.virtual.ExpressionVirtualColumn;
import javax.annotation.Nullable;
+import java.util.ArrayList;
import java.util.Arrays;
+import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.Function;
/**
+ * todo(clint): rewrite javadocs
+ *
* Represents two kinds of expression-like concepts that native Druid queries
support:
*
* (1) SimpleExtractions, which are direct column access, possibly with an
extractionFn
* (2) native Druid expressions.
*/
public class DruidExpression
{
+ public enum NodeType
+ {
+ /**
+ * constant value
+ */
+ LITERAL,
+ /**
+ * Identifier for a direct physical or virtual column access (column name
or virtual column name)
+ */
+ IDENTIFIER,
+ /**
+ * Standard native druid expression, which can compute a string that can
be parsed into {@link Expr}, or used
+ * as an {@link ExpressionVirtualColumn}
+ */
+ EXPRESSION,
+ /**
+ * Expression backed by a specialized {@link VirtualColumn}, which might
provide more optimized evaluation than
+ * is possible with the standard
+ */
+ SPECIALIZED
+ }
+
// Must be sorted
private static final char[] SAFE_CHARS = "
,._-;:(){}[]<>!@#$%^&*`~?/".toCharArray();
+ private static final VirtualColumnBuilder DEFAULT_VIRTUAL_COLUMN_BUILDER =
new ExpressionVirtualColumnBuilder();
static {
Arrays.sort(SAFE_CHARS);
}
- @Nullable
- private final SimpleExtraction simpleExtraction;
- private final String expression;
- private final TrinaryFn<String, ColumnType, ExprMacroTable, VirtualColumn>
virtualColumnFn;
+ private static String escape(final String s)
+ {
+ final StringBuilder escaped = new StringBuilder();
+ for (int i = 0; i < s.length(); i++) {
+ final char c = s.charAt(i);
+ if (Character.isLetterOrDigit(c) || Arrays.binarySearch(SAFE_CHARS, c)
>= 0) {
+ escaped.append(c);
+ } else {
+
escaped.append("\\u").append(BaseEncoding.base16().encode(Chars.toByteArray(c)));
+ }
+ }
+ return escaped.toString();
+ }
- private DruidExpression(@Nullable final SimpleExtraction simpleExtraction,
final String expression, @Nullable final TrinaryFn<String, ColumnType,
ExprMacroTable, VirtualColumn> virtualColumnFn)
Review comment:
right.. it's private. of course, uhhhh, the diff made it hard for me to
see that :P
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