Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/275#discussion_r145473757
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/expression/function/CollationKeyFunction.java
---
@@ -0,0 +1,230 @@
+/*
+ * 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.phoenix.expression.function;
+
+import java.io.DataInput;
+import java.io.IOException;
+import java.sql.SQLException;
+import java.text.Collator;
+import java.util.List;
+import java.util.Locale;
+
+import org.apache.commons.lang.BooleanUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.expression.LiteralExpression;
+import org.apache.phoenix.parse.FunctionParseNode;
+import org.apache.phoenix.schema.tuple.Tuple;
+import org.apache.phoenix.schema.types.PBoolean;
+import org.apache.phoenix.schema.types.PDataType;
+import org.apache.phoenix.schema.types.PInteger;
+import org.apache.phoenix.schema.types.PVarbinary;
+import org.apache.phoenix.schema.types.PVarchar;
+import org.apache.phoenix.util.VarBinaryFormatter;
+
+import com.force.db.i18n.LinguisticSort;
+import com.force.i18n.LocaleUtils;
+
+/**
+ * A Phoenix Function that calculates a collation key for an input
+ * string based on a caller-provided locale and collator strength and
+ * decomposition settings.
+ *
+ * The locale should be specified as xx_yy_variant where xx is the ISO
+ * 639-1 2-letter language code, yy is the the ISO 3166 2-letter
+ * country code. Both countryCode and variant are optional. For
+ * example, zh_TW_STROKE, zh_TW and zh are all valid locale
+ * representations. Note the language code, country code and variant
+ * are used as arguments to the constructor of java.util.Locale.
+ *
+ * This function uses the open-source grammaticus and i18n-util
+ * packages to obtain the collators it needs from the provided locale.
+ *
+ * The LinguisticSort implementation in i18n-util encapsulates
+ * sort-related functionality for a substantive list of locales. For
+ * each locale, it provides a collator and an Oracle-specific database
+ * function that can be used to sort strings according to the natural
+ * language rules of that locale.
+ *
+ * This function uses the collator returned by
+ * LinguisticSort.getCollator to produce a collation key for its input
+ * string. A user can expect that the sorting semantics of this
+ * function for a given locale is equivalent to the sorting behaviour
+ * of an Oracle query that is constructed using the Oracle functions
+ * returned by LinguisticSort for that locale.
+ *
+ * The optional third argument to the function is a boolean that
+ * specifies whether to use the upper-case collator (case-insensitive)
+ * returned by LinguisticSort.getUpperCaseCollator.
+ *
+ * The optional fourth and fifth arguments are used to set
+ * respectively the strength and composition of the collator returned
+ * by LinguisticSort using the setStrength and setDecomposition
+ * methods of java.text.Collator.
+ *
+ * @author snakhoda-sfdc
+ *
+ */
[email protected](name = CollationKeyFunction.NAME, args
= {
+ // input string
+ @FunctionParseNode.Argument(allowedTypes = { PVarchar.class }),
+ // ISO Code for Locale
+ @FunctionParseNode.Argument(allowedTypes = { PVarchar.class },
isConstant = true),
+ // whether to use special upper case collator
+ @FunctionParseNode.Argument(allowedTypes = { PBoolean.class },
defaultValue = "false", isConstant = true),
+ // collator strength
+ @FunctionParseNode.Argument(allowedTypes = { PInteger.class },
defaultValue = "null", isConstant = true),
+ // collator decomposition
+ @FunctionParseNode.Argument(allowedTypes = { PInteger.class },
defaultValue = "null", isConstant = true) })
+public class CollationKeyFunction extends ScalarFunction {
+
+ private static final Log LOG =
LogFactory.getLog(CollationKeyFunction.class);
+
+ public static final String NAME = "COLLATION_KEY";
+
+ private Collator collator;
+
+ public CollationKeyFunction() {
+ }
+
+ public CollationKeyFunction(List<Expression> children) throws
SQLException {
+ super(children);
+ initialize();
+ }
+
+ @Override
+ public void readFields(DataInput input) throws IOException {
+ super.readFields(input);
+ initialize();
+ }
+
+ @Override
+ public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
+ try {
+ String inputValue = getInputString(tuple, ptr);
+ byte[] collationKeyByteArray =
collator.getCollationKey(inputValue).toByteArray();
+
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("Collation key bytes: " +
VarBinaryFormatter.INSTANCE.format(collationKeyByteArray));
+ }
+
+ ptr.set(collationKeyByteArray);
+ return true;
+ } catch (ExpressionEvaluationException e) {
+ LOG.debug("ExpressionEvaluationException caught: " +
e.getMessage());
+ return false;
+ }
+ }
+
+ private void initialize() {
+ String localeISOCode = getLiteralValue(1, String.class);
+ Boolean useSpecialUpperCaseCollator = getLiteralValue(2,
Boolean.class);
+ Integer collatorStrength = getLiteralValue(3, Integer.class);
+ Integer collatorDecomposition = getLiteralValue(4,
Integer.class);
+
+ if (LOG.isDebugEnabled()) {
+ StringBuilder logInputsMessage = new StringBuilder();
+ logInputsMessage.append("Input (literal)
arguments:").append("localeISOCode: " + localeISOCode)
+ .append(", useSpecialUpperCaseCollator:
" + useSpecialUpperCaseCollator)
+ .append(", collatorStrength: " +
collatorStrength)
+ .append(", collatorDecomposition: " +
collatorDecomposition);
+ LOG.debug(logInputsMessage);
+ }
+
+ Locale locale =
LocaleUtils.get().getLocaleByIsoCode(localeISOCode);
+
+ if (LOG.isDebugEnabled()) {
+ LOG.debug(String.format("Locale: " +
locale.toLanguageTag()));
+ }
+
+ LinguisticSort linguisticSort = LinguisticSort.get(locale);
+
+ collator = BooleanUtils.isTrue(useSpecialUpperCaseCollator) ?
linguisticSort.getUpperCaseCollator(false)
+ : linguisticSort.getCollator();
+
+ if (collatorStrength != null) {
+ collator.setStrength(collatorStrength);
+ }
+
+ if (collatorDecomposition != null) {
+ collator.setDecomposition(collatorDecomposition);
+ }
+
+ if (LOG.isDebugEnabled()) {
+ LOG.debug(String.format("Collator: [strength: %d,
decomposition: %d], Special-Upper-Case: %s",
+ collator.getStrength(),
collator.getDecomposition(),
+
BooleanUtils.isTrue(useSpecialUpperCaseCollator)));
+ }
+ }
+
+ @Override
+ public PDataType getDataType() {
+ return PVarbinary.INSTANCE;
+ }
+
+ @Override
+ public String getName() {
+ return "COLLATION_KEY";
--- End diff --
Use CollationKeyFunction.NAME here instead of repeating string constant.
---
