1 files changed, 104 insertions, 0 deletions
diff --git a/predicate-search-core/src/main/java/com/yahoo/document/predicate/FeatureConjunction.java b/predicate-search-core/src/main/java/com/yahoo/document/predicate/FeatureConjunction.java
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+++ b/predicate-search-core/src/main/java/com/yahoo/document/predicate/FeatureConjunction.java
@@ -0,0 +1,104 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.document.predicate;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * A FeatureConjunction is a special type of Conjunction where
+ * all children are either a FeatureSet or a Negation (with an underlying FeatureSet).
+ * The underlying FeatureSets may only have one value.
+ *
+ * @author bjorncs
+ */
+public class FeatureConjunction extends PredicateOperator {
+    private final List<Predicate> operands;
+
+    public FeatureConjunction(List<Predicate> operands) {
+        validateOperands(operands);
+        this.operands = new ArrayList<>(operands);
+    }
+
+    private static void validateOperands(List<Predicate> operands) {
+        if (operands.size() <= 1) {
+            throw new IllegalArgumentException("Number of operands must 2 or more, was: " + operands.size());
+        }
+        if (!operands.stream()
+                .allMatch(FeatureConjunction::isValidFeatureConjunctionOperand)) {
+            throw new IllegalArgumentException(
+                    "A FeatureConjunction may only contain instances of Negation and FeatureSet, " +
+                            "and a FeatureSet may only have one value.");
+        }
+
+        long uniqueKeys = operands.stream().map(FeatureConjunction::getFeatureSetKey).distinct().count();
+        if (operands.size() > uniqueKeys) {
+            throw new IllegalArgumentException("Each FeatureSet key must have a unique key.");
+        }
+    }
+
+    private static String getFeatureSetKey(Predicate predicate) {
+        if (predicate instanceof FeatureSet) {
+            return ((FeatureSet) predicate).getKey();
+        } else {
+            Negation negation = (Negation) predicate;
+            return ((FeatureSet) negation.getOperand()).getKey();
+        }
+    }
+
+    public static boolean isValidFeatureConjunctionOperand(Predicate operand) {
+        return operand instanceof Negation
+                    && ((Negation) operand).getOperand() instanceof FeatureSet
+                    && isValidFeatureConjunctionOperand(((Negation) operand).getOperand())
+                || operand instanceof FeatureSet && ((FeatureSet) operand).getValues().size() == 1;
+    }
+
+    @Override
+    public List<Predicate> getOperands() {
+        return operands;
+    }
+
+    @Override
+    protected void appendTo(StringBuilder out) {
+        for (Iterator<Predicate> it = operands.iterator(); it.hasNext(); ) {
+            Predicate operand = it.next();
+            if (operand instanceof Disjunction) {
+                out.append('(');
+                operand.appendTo(out);
+                out.append(')');
+            } else {
+                operand.appendTo(out);
+            }
+            if (it.hasNext()) {
+                out.append(" conj ");
+            }
+        }
+    }
+
+    @Override
+    public FeatureConjunction clone() throws CloneNotSupportedException {
+        return new FeatureConjunction(operands);
+    }
+
+    @Override
+    public int hashCode() {
+        return operands.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (!(obj instanceof FeatureConjunction)) {
+            return false;
+        }
+        FeatureConjunction rhs = (FeatureConjunction)obj;
+        if (!operands.equals(rhs.operands)) {
+            return false;
+        }
+        return true;
+    }
+
+
+}