io.druid.query.dimension.RegexFilteredDimensionSpec.java Source code

Introduction

Here is the source code for io.druid.query.dimension.RegexFilteredDimensionSpec.java

Source

/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.query.dimension;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import io.druid.java.util.common.StringUtils;
import io.druid.query.filter.DimFilterUtils;
import io.druid.segment.DimensionSelector;

import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;

/**
 */
public class RegexFilteredDimensionSpec extends BaseFilteredDimensionSpec {

    private static final byte CACHE_TYPE_ID = 0x2;

    private final String pattern;

    private final Pattern compiledRegex;

    public RegexFilteredDimensionSpec(@JsonProperty("delegate") DimensionSpec delegate,
            @JsonProperty("pattern") String pattern //rows not matching the pattern will be discarded
    ) {
        super(delegate);
        this.pattern = Preconditions.checkNotNull(pattern, "pattern must not be null");
        this.compiledRegex = Pattern.compile(pattern);
    }

    @JsonProperty
    public String getPattern() {
        return pattern;
    }

    @Override
    public DimensionSelector decorate(final DimensionSelector selector) {
        if (selector == null) {
            return selector;
        }

        int count = 0;
        final Map<Integer, Integer> forwardMapping = new HashMap<>();

        final int selectorCardinality = selector.getValueCardinality();
        if (selectorCardinality < 0) {
            throw new UnsupportedOperationException("Cannot decorate a selector with no dictionary");
        }

        for (int i = 0; i < selectorCardinality; i++) {
            if (compiledRegex.matcher(Strings.nullToEmpty(selector.lookupName(i))).matches()) {
                forwardMapping.put(i, count++);
            }
        }

        final int[] reverseMapping = new int[forwardMapping.size()];
        for (Map.Entry<Integer, Integer> e : forwardMapping.entrySet()) {
            reverseMapping[e.getValue().intValue()] = e.getKey().intValue();
        }
        return BaseFilteredDimensionSpec.decorate(selector, forwardMapping, reverseMapping);
    }

    @Override
    public byte[] getCacheKey() {
        byte[] delegateCacheKey = delegate.getCacheKey();
        byte[] regexBytes = StringUtils.toUtf8(pattern);
        return ByteBuffer.allocate(2 + delegateCacheKey.length + regexBytes.length).put(CACHE_TYPE_ID)
                .put(delegateCacheKey).put(DimFilterUtils.STRING_SEPARATOR).put(regexBytes).array();
    }

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

        RegexFilteredDimensionSpec that = (RegexFilteredDimensionSpec) o;

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

    }

    @Override
    public int hashCode() {
        int result = delegate.hashCode();
        result = 31 * result + pattern.hashCode();
        return result;
    }

    @Override
    public String toString() {
        return "RegexFilteredDimensionSpec{" + "pattern='" + pattern + '\'' + '}';
    }
}