diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java b/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java
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+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java
@@ -0,0 +1,172 @@
+/*
+ * Copyright 2017-present Open Networking Laboratory
+ *
+ * Licensed 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.onosproject.net.pi.impl;
+
+import org.apache.commons.lang3.tuple.Pair;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.pi.model.PiMatchType;
+
+import java.util.Optional;
+
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+import static org.onlab.util.ImmutableByteSequence.fit;
+
+/**
+ * Abstract implementation of a criterion translator that opportunistically tries to generate different types of match
+ * based on an initialization method. It throws an exception when a safe translation is not possible, e.g. when trying
+ * to translate a masked criterion to an exact match.
+ */
+abstract class AbstractCriterionTranslator implements CriterionTranslator {
+
+    private PiMatchType initType;
+    private int bitWidth;
+    private ImmutableByteSequence value;
+    private ImmutableByteSequence mask;
+    private Integer prefixLength;
+
+    /**
+     * Initializes the translator as an exact match.
+     *
+     * @param value     exact match value
+     * @param bitWidth  field bit-width
+     * @throws ByteSequenceTrimException if the match value cannot be trimmed to fit the field match bit-width
+     */
+    void initAsExactMatch(ImmutableByteSequence value, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.EXACT;
+    }
+
+    /**
+     * Initializes the translator as a ternary match.
+     *
+     * @param value     match value
+     * @param mask      match mask
+     * @param bitWidth  field bit-width
+     * @throws ByteSequenceTrimException if the match value or mask cannot be trimmed to fit the field match bit-width
+     */
+    void initAsTernaryMatch(ImmutableByteSequence value, ImmutableByteSequence mask, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.mask = fit(mask, bitWidth);
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.TERNARY;
+    }
+
+    /**
+     * Initializes the translator as a longest-prefix match.
+     *
+     * @param value        match value
+     * @param prefixLength prefix length
+     * @param bitWidth     field bit-width
+     * @throws ByteSequenceTrimException if the match value cannot be trimmed to fit the field match bit-width
+     */
+    void initAsLpm(ImmutableByteSequence value, int prefixLength, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.prefixLength = prefixLength;
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.LPM;
+    }
+
+    @Override
+    public ImmutableByteSequence exactMatch() throws CriterionTranslatorException {
+        switch (initType) {
+            case EXACT:
+                break;
+            case TERNARY:
+                ImmutableByteSequence exactMask = ImmutableByteSequence.ofOnes(value.size());
+                if (!mask.equals(exactMask)) {
+                    throw new CriterionTranslator.CriterionTranslatorException(
+                            "trying to use masked field as an exact match, but mask is not exact");
+                }
+                break;
+            case LPM:
+                if (prefixLength < bitWidth) {
+                    throw new CriterionTranslator.CriterionTranslatorException(
+                            "trying to use LPM field as an exact match, but prefix is not full");
+                }
+                break;
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+        return value;
+    }
+
+    @Override
+    public Pair<ImmutableByteSequence, ImmutableByteSequence> ternaryMatch() {
+        switch (initType) {
+            case EXACT:
+                mask = ImmutableByteSequence.ofOnes(value.size());
+                break;
+            case TERNARY:
+                break;
+            case LPM:
+                mask = getMaskFromPrefixLength(prefixLength, value.size());
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+
+        return Pair.of(value, mask);
+    }
+
+    @Override
+    public Pair<ImmutableByteSequence, Integer> lpmMatch() throws CriterionTranslatorException {
+        switch (initType) {
+            case EXACT:
+                prefixLength = bitWidth;
+                break;
+            case TERNARY:
+                prefixLength = getPrefixLengthFromMask(mask).orElseThrow(
+                        () -> new CriterionTranslatorException(
+                                "trying to use masked field as a longest-prefix match, " +
+                                        "but mask is not equivalent to a prefix length"));
+                break;
+            case LPM:
+                break;
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+
+        return Pair.of(value, prefixLength);
+    }
+
+    /**
+     * Returns a bit mask equivalent to the given prefix length.
+     *
+     * @param prefixLength prefix length (in bits)
+     * @param maskSize     mask size (in bytes)
+     * @return a byte sequence
+     */
+    private ImmutableByteSequence getMaskFromPrefixLength(int prefixLength, int maskSize) {
+        // TODO: implement.
+        throw new RuntimeException("getMaskFromPrefixLength() not implemented yet.");
+    }
+
+    /**
+     * Checks that the given mask is equivalent to a longest-prefix match and returns the prefix length. If not
+     * possible, the optional value will not be present.
+     *
+     * @param mask byte sequence
+     * @return optional prefix length
+     */
+    private Optional<Integer> getPrefixLengthFromMask(ImmutableByteSequence mask) {
+        // TODO: implement.
+        throw new RuntimeException("getPrefixLengthFromMask() not implemented yet.");
+    }
+}