apache · suneet-s · Sep 14, 2020 · Sep 3, 2020 · Sep 4, 2020 · Sep 4, 2020
diff --git a/docs/misc/math-expr.md b/docs/misc/math-expr.md
@@ -78,6 +78,8 @@ The following built-in functions are available.
 |parse_long|parse_long(string[, radix]) parses a string as a long with the given radix, or 10 (decimal) if a radix is not provided.|
 |regexp_extract|regexp_extract(expr, pattern[, index]) applies a regular expression pattern and extracts a capture group index, or null if there is no match. If index is unspecified or zero, returns the substring that matched the pattern. The pattern may match anywhere inside `expr`; if you want to match the entire string instead, use the `^` and `$` markers at the start and end of your pattern.|
 |regexp_like|regexp_like(expr, pattern) returns whether `expr` matches regular expression `pattern`. The pattern may match anywhere inside `expr`; if you want to match the entire string instead, use the `^` and `$` markers at the start and end of your pattern. |
+|contains_string|contains_string(expr, string) returns whether `expr` contains `string` as a substring. This method is case-sensitive.|
+|icontains_string|contains_string(expr, string) returns whether `expr` contains `string` as a substring. This method is case-insensitive.|
 |replace|replace(expr, pattern, replacement) replaces pattern with replacement|
 |substring|substring(expr, index, length) behaves like java.lang.String's substring|
 |right|right(expr, length) returns the rightmost length characters from a string|

diff --git a/docs/querying/sql.md b/docs/querying/sql.md
@@ -397,6 +397,8 @@ String functions accept strings, and return a type appropriate to the function.
 |`POSITION(needle IN haystack [FROM fromIndex])`|Returns the index of needle within haystack, with indexes starting from 1. The search will begin at fromIndex, or 1 if fromIndex is not specified. If the needle is not found, returns 0.|
 |`REGEXP_EXTRACT(expr, pattern, [index])`|Apply regular expression `pattern` to `expr` and extract a capture group, or `NULL` if there is no match. If index is unspecified or zero, returns the first substring that matched the pattern. The pattern may match anywhere inside `expr`; if you want to match the entire string instead, use the `^` and `$` markers at the start and end of your pattern. Note: when `druid.generic.useDefaultValueForNull = true`, it is not possible to differentiate an empty-string match from a non-match (both will return `NULL`).|
 |`REGEXP_LIKE(expr, pattern)`|Returns whether `expr` matches regular expression `pattern`. The pattern may match anywhere inside `expr`; if you want to match the entire string instead, use the `^` and `$` markers at the start and end of your pattern. Similar to [`LIKE`](#comparison-operators), but uses regexps instead of LIKE patterns. Especially useful in WHERE clauses.|
+|`CONTAINS_STRING(<expr>, str)`|Returns true if the `str` is a substring of `expr`.|
+|`ICONTAINS_STRING(<expr>, str)`|Returns true if the `str` is a substring of `expr`. The match is case-insensitive.|
 |`REPLACE(expr, pattern, replacement)`|Replaces pattern with replacement in expr, and returns the result.|
 |`STRPOS(haystack, needle)`|Returns the index of needle within haystack, with indexes starting from 1. If the needle is not found, returns 0.|
 |`SUBSTRING(expr, index, [length])`|Returns a substring of expr starting at index, with a max length, both measured in UTF-16 code units.|

diff --git a/...ing/src/main/java/org/apache/druid/query/expression/CaseInsensitiveContainsExprMacro.java b/...ing/src/main/java/org/apache/druid/query/expression/CaseInsensitiveContainsExprMacro.java
@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.query.expression;
+
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.math.expr.Expr;
+import org.apache.druid.math.expr.ExprMacroTable;
+
+import java.util.List;
+
+/**
+ * This class implements a function that checks if one string contains another string. It is required that second
+ * string be a literal. This expression is case-insensitive.
+ * signature:
+ * long contains_string(string, string)
+ * <p>
+ * Examples:
+ * - {@code contains_string("foobar", "bar") - 1 }
+ * - {@code contains_string("foobar", "car") - 0 }
+ * - {@code contains_string("foobar", "Bar") - 1 }
+ * <p>
+ * See {@link ContainsExprMacro} for the case-sensitive version.
+ */
+
+public class CaseInsensitiveContainsExprMacro implements ExprMacroTable.ExprMacro
+{
+  public static final String FN_NAME = "icontains_string";
+
+  @Override
+  public String name()
+  {
+    return FN_NAME;
+  }
+
+  @Override
+  public Expr apply(final List<Expr> args)
+  {
+    if (args.size() != 2) {
+      throw new IAE("Function[%s] must have 2 arguments", name());
+    }
+
+    final Expr arg = args.get(0);
+    final Expr searchStr = args.get(1);
+    return new ContainsExpr(FN_NAME, arg, searchStr, false);
+  }
+}
diff --git a/processing/src/main/java/org/apache/druid/query/expression/ContainsExpr.java b/processing/src/main/java/org/apache/druid/query/expression/ContainsExpr.java
@@ -0,0 +1,101 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.query.expression;
+
+import org.apache.druid.common.config.NullHandling;
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.math.expr.Expr;
+import org.apache.druid.math.expr.ExprEval;
+import org.apache.druid.math.expr.ExprMacroTable;
+import org.apache.druid.math.expr.ExprType;
+
+import javax.annotation.Nonnull;
+import java.util.function.Function;
+
+/**
+ * {@link Expr} class returned by {@link ContainsExprMacro} and {@link CaseInsensitiveContainsExprMacro} for
+ * evaluating the expression.
+ */
+class ContainsExpr extends ExprMacroTable.BaseScalarUnivariateMacroFunctionExpr
+{
+  private final Function<String, Boolean> searchFunction;
+  private final Expr searchStrExpr;
+
+  ContainsExpr(String functioName, Expr arg, Expr searchStrExpr, boolean caseSensitive)
+  {
+    super(functioName, arg);
+    this.searchStrExpr = validateSearchExpr(searchStrExpr, functioName);
+    // Creates the function eagerly to avoid branching in eval.
+    this.searchFunction = createFunction(searchStrExpr, caseSensitive);
+  }
+
+  private ContainsExpr(String functioName, Expr arg, Expr searchStrExpr, Function<String, Boolean> searchFunction)
+  {
+    super(functioName, arg);
+    this.searchFunction = searchFunction;
+    this.searchStrExpr = validateSearchExpr(searchStrExpr, functioName);
+  }
+
+  @Nonnull
+  @Override
+  public ExprEval eval(final Expr.ObjectBinding bindings)
+  {
+    final String s = NullHandling.nullToEmptyIfNeeded(arg.eval(bindings).asString());
+
+    if (s == null) {
+      // same behavior as regexp_like.
-      // same behavior as regexp_like.
+      // same behavior as ContainsSearchQuerySpec#accept
-      // same behavior as regexp_like.
+      // same behavior as ContainsSearchQuerySpec#accept
+      return ExprEval.of(false, ExprType.LONG);
+    } else {
+      final boolean doesContain = searchFunction.apply(s);
+      return ExprEval.of(doesContain, ExprType.LONG);
+    }
+  }
+
+  @Override
+  public Expr visit(Expr.Shuttle shuttle)
+  {
+    Expr newArg = arg.visit(shuttle);
+    return shuttle.visit(new ContainsExpr(name, newArg, searchStrExpr, searchFunction));
+  }
+
+  @Override
+  public String stringify()
+  {
+    return StringUtils.format("%s(%s, %s)", name, arg.stringify(), searchStrExpr.stringify());
+  }
+
+  private Function<String, Boolean> createFunction(Expr searchStrExpr, boolean caseSensitive)
+  {
+    String searchStr = StringUtils.nullToEmptyNonDruidDataString((String) searchStrExpr.getLiteralValue());
+    if (caseSensitive) {
+      return s -> s.contains(searchStr);
+    }
+    return s -> org.apache.commons.lang.StringUtils.containsIgnoreCase(s, searchStr);
+  }
+
+  private Expr validateSearchExpr(Expr searchExpr, String functioName)
+  {
+    if (!ExprUtils.isStringLiteral(searchExpr)) {
+      throw new IAE("Function[%s] substring must be a string literal", functioName);
+    }
+    return searchExpr;
+  }
+}
diff --git a/processing/src/main/java/org/apache/druid/query/expression/ContainsExprMacro.java b/processing/src/main/java/org/apache/druid/query/expression/ContainsExprMacro.java
@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.query.expression;
+
+import org.apache.druid.java.util.common.IAE;
+import org.apache.druid.math.expr.Expr;
+import org.apache.druid.math.expr.ExprMacroTable;
+
+import java.util.List;
+
+/**
+ * This class implements a function that checks if one string contains another string. It is required that second
+ * string be a literal. This expression is case-sensitive.
+ * signature:
+ * long contains_string(string, string)
+ * <p>
+ * Examples:
+ * - {@code contains_string("foobar", "bar") - 1 }
+ * - {@code contains_string("foobar", "car") - 0 }
+ * - {@code contains_string("foobar", "Bar") - 0 }
+ * <p>
+ * See {@link CaseInsensitiveContainsExprMacro} for the case-insensitive version.
+ */
+public class ContainsExprMacro implements ExprMacroTable.ExprMacro
+{
+  public static final String FN_NAME = "contains_string";
+
+  @Override
+  public String name()
+  {
+    return FN_NAME;
+  }
+
+  @Override
+  public Expr apply(final List<Expr> args)
+  {
+    if (args.size() != 2) {
+      throw new IAE("Function[%s] must have 2 arguments", name());
+    }
+
+    final Expr arg = args.get(0);
+    final Expr searchStr = args.get(1);
+    return new ContainsExpr(FN_NAME, arg, searchStr, true);
+  }
+}