1 files changed, 34 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/yql/NodeTypeChecker.java b/container-search/src/main/java/com/yahoo/search/yql/NodeTypeChecker.java
new file mode 100644
index 00000000000..c407689e107
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/yql/NodeTypeChecker.java
@@ -0,0 +1,34 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.yql;
+
+import com.google.common.base.Joiner;
+import com.google.common.base.Preconditions;
+import java.util.Set;
+
+/**
+ * Check that an argument is an OperatorNode of a particular operator set.
+ */
+class NodeTypeChecker extends OperatorTypeChecker {
+
+    private final Class<? extends Operator> operatorType;
+    private final Set<? extends Operator> operators;
+
+    public NodeTypeChecker(Operator parent, int idx, Class<? extends Operator> operatorType, Set<? extends Operator> operators) {
+        super(parent, idx);
+        this.operatorType = operatorType;
+        this.operators = operators;
+    }
+
+    @Override
+    public void check(Object argument) {
+        Preconditions.checkNotNull(argument, "Argument %s of %s must not be null", idx, parent);
+        Preconditions.checkArgument(argument instanceof OperatorNode, "Argument %s of %s must be an OperatorNode<%s> (is %s).", idx, parent, operatorType.getName(), argument.getClass());
+        OperatorNode<?> node = (OperatorNode<?>) argument;
+        Operator op = node.getOperator();
+        Preconditions.checkArgument(operatorType.isInstance(op), "Argument %s of %s must be an OperatorNode<%s> (is: %s).", idx, parent, operatorType.getName(), op.getClass());
+        if (!operators.isEmpty()) {
+            Preconditions.checkArgument(operators.contains(op), "Argument %s of %s must be %s (is %s).", idx, parent, Joiner.on("|").join(operators), op);
+        }
+    }
+
+}