/*
* 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.util.List;
import java.util.regex.Pattern;
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.Argument;
import org.apache.phoenix.parse.FunctionParseNode.BuiltInFunction;
import org.apache.phoenix.schema.PDataType;
import org.apache.phoenix.schema.tuple.Tuple;
/**
*
* Function similar to the regexp_replace function in Postgres, which is used to pattern
* match a segment of the string. Usage:
* REGEXP_REPLACE(<source_char>,<pattern>,<replace_string>)
* source_char is the string in which we want to perform string replacement. pattern is a
* Java compatible regular expression string, and we replace all the matching part with
* replace_string. The first 2 arguments are required and are {@link org.apache.phoenix.schema.PDataType#VARCHAR},
* the replace_string is default to empty string.
*
* The function returns a {@link org.apache.phoenix.schema.PDataType#VARCHAR}
*
*
* @since 0.1
*/
@BuiltInFunction(name=RegexpReplaceFunction.NAME, args= {
@Argument(allowedTypes={PDataType.VARCHAR}),
@Argument(allowedTypes={PDataType.VARCHAR}),
@Argument(allowedTypes={PDataType.VARCHAR},defaultValue="null")} )
public class RegexpReplaceFunction extends ScalarFunction {
public static final String NAME = "REGEXP_REPLACE";
private boolean hasReplaceStr;
private Pattern pattern;
public RegexpReplaceFunction() { }
// Expect 1 arguments, the pattern.
public RegexpReplaceFunction(List<Expression> children) {
super(children);
init();
}
private void init() {
hasReplaceStr = ((LiteralExpression)getReplaceStrExpression()).getValue() != null;
Object patternString = ((LiteralExpression)children.get(1)).getValue();
if (patternString != null) {
pattern = Pattern.compile((String)patternString);
}
}
@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
// Can't parse if there is no replacement pattern.
if (pattern == null) {
return false;
}
Expression sourceStrExpression = getSourceStrExpression();
if (!sourceStrExpression.evaluate(tuple, ptr)) {
return false;
}
String sourceStr = (String)PDataType.VARCHAR.toObject(ptr, sourceStrExpression.getColumnModifier());
if (sourceStr == null) {
return false;
}
String replaceStr;
if (hasReplaceStr) {
Expression replaceStrExpression = this.getReplaceStrExpression();
if (!replaceStrExpression.evaluate(tuple, ptr)) {
return false;
}
replaceStr = (String)PDataType.VARCHAR.toObject(ptr, replaceStrExpression.getColumnModifier());
} else {
replaceStr = "";
}
String replacedStr = pattern.matcher(sourceStr).replaceAll(replaceStr);
ptr.set(PDataType.VARCHAR.toBytes(replacedStr));
return true;
}
private Expression getSourceStrExpression() {
return children.get(0);
}
private Expression getReplaceStrExpression() {
return children.get(2);
}
@Override
public PDataType getDataType() {
return PDataType.VARCHAR;
}
@Override
public void readFields(DataInput input) throws IOException {
super.readFields(input);
init();
}
@Override
public String getName() {
return NAME;
}
}