com.metamx.druid.query.metadata.ListColumnIncluderator.java Source code

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Here is the source code for com.metamx.druid.query.metadata.ListColumnIncluderator.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.query.metadata;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.common.base.Charsets;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.List;
import java.util.Set;

/**
 */
public class ListColumnIncluderator implements ColumnIncluderator {
    private final Set<String> columns;

    @JsonCreator
    public ListColumnIncluderator(@JsonProperty("columns") List<String> columns) {
        this.columns = Sets.newTreeSet(String.CASE_INSENSITIVE_ORDER);
        this.columns.addAll(columns);
    }

    @JsonProperty
    public Set<String> getColumns() {
        return Collections.unmodifiableSet(columns);
    }

    @Override
    public boolean include(String columnName) {
        return columns.contains(columnName);
    }

    @Override
    public byte[] getCacheKey() {
        int size = 1;
        List<byte[]> columns = Lists.newArrayListWithExpectedSize(this.columns.size());

        for (String column : this.columns) {
            final byte[] bytes = column.getBytes(Charsets.UTF_8);
            columns.add(bytes);
            size += bytes.length;
        }

        final ByteBuffer bytes = ByteBuffer.allocate(size).put(LIST_CACHE_PREFIX);
        for (byte[] column : columns) {
            bytes.put(column);
        }

        return bytes.array();
    }
}