org.apache.hadoop.hive.accumulo.columns.ColumnEncoding.java Source code

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Here is the source code for org.apache.hadoop.hive.accumulo.columns.ColumnEncoding.java

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/*
 * 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.hadoop.hive.accumulo.columns;

import java.util.HashMap;
import java.util.Map.Entry;

import org.apache.hadoop.hive.accumulo.AccumuloHiveConstants;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

/**
 * Encapsulate the encoding of values within the given column in Accumulo
 */
public enum ColumnEncoding {
    STRING("string", "s"), BINARY("binary", "b");

    private static final HashMap<String, ColumnEncoding> CODE_CACHE = new HashMap<String, ColumnEncoding>(),
            NAME_CACHE = new HashMap<String, ColumnEncoding>();

    static {
        CODE_CACHE.put(STRING.getCode(), STRING);
        CODE_CACHE.put(BINARY.getCode(), BINARY);

        NAME_CACHE.put(STRING.getName(), STRING);
        NAME_CACHE.put(BINARY.getName(), BINARY);
    }

    private final String name;
    private final String code;

    private ColumnEncoding(String name, String code) {
        this.name = name;
        this.code = code;
    }

    public String getName() {
        return this.name;
    }

    public String getCode() {
        return code;
    }

    /**
     * Get the ColumnEncoding which has the given code.
     *
     * @param code
     *          The one-character 'code' which uniquely identifies the ColumnEncoding
     * @return The ColumnEncoding with the code equal to the provided argument
     */
    public static ColumnEncoding fromCode(String code) {
        if (!CODE_CACHE.containsKey(code)) {
            throw new IllegalArgumentException("No ColumnEncoding defined with code " + code);
        }

        return CODE_CACHE.get(code);
    }

    public static ColumnEncoding fromName(String name) {
        if (!NAME_CACHE.containsKey(name)) {
            throw new IllegalArgumentException("No ColumnEncoding defined with name " + name);
        }

        return NAME_CACHE.get(name);
    }

    public static ColumnEncoding get(String nameOrCode) {
        ColumnEncoding encoding = CODE_CACHE.get(nameOrCode);
        if (null != encoding) {
            return encoding;
        }

        encoding = NAME_CACHE.get(nameOrCode);
        if (null != encoding) {
            return encoding;
        }

        throw new IllegalArgumentException("No ColumnEncoding defined for " + nameOrCode);
    }

    public static ColumnEncoding getFromMapping(String columnMapping) {
        Preconditions.checkNotNull(columnMapping);

        String encoding = getColumnEncoding(columnMapping);

        return get(encoding);
    }

    /**
     * Determines if a custom encoding was specified for the give column.
     *
     * @param columnMapping
     *          The mapping from Hive column to an Accumulo column
     * @return True if the column mapping string specifies an encoding, false otherwise
     */
    public static boolean hasColumnEncoding(String columnMapping) {
        Preconditions.checkNotNull(columnMapping);

        int offset = columnMapping.lastIndexOf(AccumuloHiveConstants.POUND);

        // Make sure that the '#' wasn't escaped
        if (0 < offset && AccumuloHiveConstants.ESCAPE == columnMapping.charAt(offset - 1)) {
            // The encoding name/codes don't contain pound signs
            return false;
        }

        return -1 != offset;
    }

    public static String getColumnEncoding(String columnMapping) {
        int offset = columnMapping.lastIndexOf(AccumuloHiveConstants.POUND);

        // Make sure that the '#' wasn't escaped
        if (0 < offset && AccumuloHiveConstants.ESCAPE == columnMapping.charAt(offset - 1)) {
            throw new IllegalArgumentException(
                    "Column mapping did not contain a column encoding: " + columnMapping);
        }

        return columnMapping.substring(offset + 1);
    }

    public static ColumnEncoding getDefault() {
        return STRING;
    }

    /**
     * Removes the column encoding code and separator from the original column mapping string. Throws
     * an IllegalArgumentException if this method is called on a string that doesn't contain a code.
     *
     * @param columnMapping
     *          The mapping from Hive column to Accumulo column
     * @return The column mapping with the code removed
     */
    public static String stripCode(String columnMapping) {
        Preconditions.checkNotNull(columnMapping);

        int offset = columnMapping.lastIndexOf(AccumuloHiveConstants.POUND);
        if (-1 == offset || (0 < offset && AccumuloHiveConstants.ESCAPE == columnMapping.charAt(offset - 1))) {
            throw new IllegalArgumentException("Provided column mapping does not define a column encoding");
        }

        return columnMapping.substring(0, offset);
    }

    public static boolean isMapEncoding(String columnEncoding) {
        return -1 != columnEncoding.indexOf(AccumuloHiveConstants.COLON);
    }

    public static Entry<ColumnEncoding, ColumnEncoding> getMapEncoding(String columnEncoding) {
        int index = columnEncoding.indexOf(AccumuloHiveConstants.COLON);
        if (-1 == index) {
            throw new IllegalArgumentException(
                    "Serialized column encoding did not contain a pair of encodings to split");
        }

        String encoding1 = columnEncoding.substring(0, index), encoding2 = columnEncoding.substring(index + 1);

        return Maps.immutableEntry(get(encoding1), get(encoding2));
    }
}