1 files changed, 84 insertions, 0 deletions
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/GetFieldExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/GetFieldExpression.java
new file mode 100644
index 00000000000..6cc06953437
--- /dev/null
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/GetFieldExpression.java
@@ -0,0 +1,84 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.indexinglanguage.expressions;
+
+import com.yahoo.document.DataType;
+import com.yahoo.document.DocumentType;
+import com.yahoo.document.Field;
+import com.yahoo.document.StructuredDataType;
+import com.yahoo.document.datatypes.FieldValue;
+import com.yahoo.document.datatypes.StructuredFieldValue;
+
+/**
+ * @author <a href="mailto:simon@yahoo-inc.com">Simon Thoresen</a>
+ */
+public class GetFieldExpression extends Expression {
+
+    private final String fieldName;
+
+    public GetFieldExpression(String fieldName) {
+        this.fieldName = fieldName;
+    }
+
+    public String getFieldName() {
+        return fieldName;
+    }
+
+    @Override
+    protected void doExecute(ExecutionContext ctx) {
+        FieldValue input = ctx.getValue();
+        if (!(input instanceof StructuredFieldValue)) {
+            throw new IllegalArgumentException("Expected structured input, got " + input.getDataType().getName() + ".");
+        }
+        StructuredFieldValue struct = (StructuredFieldValue)input;
+        Field field = struct.getField(fieldName);
+        if (field == null) {
+            throw new IllegalArgumentException("Field '" + fieldName + "' not found.");
+        }
+        ctx.setValue(struct.getFieldValue(field));
+    }
+
+    @Override
+    protected void doVerify(VerificationContext ctx) {
+        DataType input = ctx.getValue();
+        if (!(input instanceof StructuredDataType)) {
+            throw new VerificationException(this, "Expected structured input, got " + input.getName() + ".");
+        }
+        Field field = ((StructuredDataType)input).getField(fieldName);
+        if (field == null) {
+            throw new VerificationException(this, "Field '" + fieldName + "' not found.");
+        }
+        ctx.setValue(field.getDataType());
+    }
+
+    @Override
+    public DataType requiredInputType() {
+        return UnresolvedDataType.INSTANCE;
+    }
+
+    @Override
+    public DataType createdOutputType() {
+        return UnresolvedDataType.INSTANCE;
+    }
+
+    @Override
+    public String toString() {
+        return "get_field " + fieldName;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof GetFieldExpression)) {
+            return false;
+        }
+        GetFieldExpression rhs = (GetFieldExpression)obj;
+        if (!fieldName.equals(rhs.fieldName)) {
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        return getClass().hashCode() + fieldName.hashCode();
+    }
+}