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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-4237) Allow sorting on (Java) collation keys for non-English locales
Date Wed, 18 Oct 2017 16:44:01 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-4237?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16209667#comment-16209667
] 

ASF GitHub Bot commented on PHOENIX-4237:
-----------------------------------------

Github user JamesRTaylor commented on a diff in the pull request:

    https://github.com/apache/phoenix/pull/275#discussion_r145473581
  
    --- 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
    + *
    + */
    +@FunctionParseNode.BuiltInFunction(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";
    +	}
    +
    +	/**
    +	 * Get the string for which the collation key needs to be calculated (the
    +	 * first argument)
    +	 */
    +	private String getInputString(Tuple tuple, ImmutableBytesWritable ptr) {
    +		Expression expression = getChildren().get(0);
    +		if (!expression.evaluate(tuple, ptr)) {
    +			throw new ExpressionEvaluationException(expression);
    +		}
    +		String inputString = (String) PVarchar.INSTANCE.toObject(ptr, expression.getSortOrder());
    +		if (LOG.isDebugEnabled()) {
    +			LOG.debug("inputString: " + inputString);
    +		}
    +		return inputString;
    +	}
    +
    +	private <T> T getLiteralValue(int childIndex, Class<T> type) {
    +		Expression expression = getChildren().get(childIndex);
    +		if (LOG.isDebugEnabled()) {
    +			LOG.debug("child: " + childIndex + ", expression: " + expression);
    +		}
    +		if (!(expression instanceof LiteralExpression)) {
    +			throw new ExpressionEvaluationException(expression);
    +		}
    --- End diff --
    
    This if statement isn't necessary. Phoenix already checks this and throws if it's not
the case based on your declaration of the argument as being a constant.


> Allow sorting on (Java) collation keys for non-English locales
> --------------------------------------------------------------
>
>                 Key: PHOENIX-4237
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4237
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Shehzaad Nakhoda
>             Fix For: 4.12.0
>
>
> Strings stored via Phoenix can be composed from a subset of the entire set of Unicode
characters. The natural sort order for strings for different languages often differs from
the order dictated by the binary representation of the characters of these strings. Java provides
the idea of a Collator which given an input string and a (language) locale can generate a
Collation Key which can then be used to compare strings in that natural order.
> Salesforce has recently open-sourced grammaticus. IBM has open-sourced ICU4J some time
ago. These technologies can be combined to provide a robust new Phoenix function that can
be used in an ORDER BY clause to sort strings according to the user's locale.



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