io.druid.query.extraction.RegexDimExtractionFn.java Source code

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Here is the source code for io.druid.query.extraction.RegexDimExtractionFn.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * 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 io.druid.query.extraction;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.metamx.common.StringUtils;

import java.nio.ByteBuffer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 */
public class RegexDimExtractionFn extends DimExtractionFn {
    private static final byte CACHE_TYPE_ID = 0x1;

    private final String expr;
    private final Pattern pattern;

    @JsonCreator
    public RegexDimExtractionFn(@JsonProperty("expr") String expr) {
        Preconditions.checkNotNull(expr, "expr must not be null");

        this.expr = expr;
        this.pattern = Pattern.compile(expr);
    }

    @Override
    public byte[] getCacheKey() {
        byte[] exprBytes = StringUtils.toUtf8(expr);
        return ByteBuffer.allocate(1 + exprBytes.length).put(CACHE_TYPE_ID).put(exprBytes).array();
    }

    @Override
    public String apply(String dimValue) {
        if (dimValue == null) {
            return null;
        }
        Matcher matcher = pattern.matcher(dimValue);
        return Strings.emptyToNull(matcher.find() ? matcher.group(1) : dimValue);
    }

    @JsonProperty("expr")
    public String getExpr() {
        return expr;
    }

    @Override
    public boolean preservesOrdering() {
        return false;
    }

    @Override
    public ExtractionType getExtractionType() {
        return ExtractionType.MANY_TO_ONE;
    }

    @Override
    public String toString() {
        return String.format("regex(%s)", expr);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        RegexDimExtractionFn that = (RegexDimExtractionFn) o;

        if (!expr.equals(that.expr)) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        return expr.hashCode();
    }
}