co.cask.cdap.common.conf.ConfigurationUtil.java Source code

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Here is the source code for co.cask.cdap.common.conf.ConfigurationUtil.java

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/*
 * Copyright  2014-2016 Cask Data, 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 co.cask.cdap.common.conf;

import co.cask.cdap.common.io.Codec;
import com.google.common.base.Charsets;
import org.apache.hadoop.conf.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.Nullable;

/**
 * Has methods to set/get objects into Configuration object.
 * Also has methods for prefixing a set of configurations with a name and also for extracting the prefixed parameters.
 */
public final class ConfigurationUtil {

    private static final Logger LOG = LoggerFactory.getLogger(ConfigurationUtil.class);

    public static <T> void set(Configuration conf, String key, Codec<T> codec, T obj) throws IOException {
        String value = new String(codec.encode(obj), Charsets.UTF_8);
        LOG.trace("Serializing {} {}", key, value);
        conf.set(key, value);
    }

    public static <T> T get(Configuration conf, String key, Codec<T> codec) throws IOException {
        String value = conf.get(key);
        LOG.trace("De-serializing {} {}", key, value);
        // Using Latin-1 encoding so that all bytes can be encoded as string. UTF-8 has some invalid bytes that will get
        // skipped.
        return codec.decode(value == null ? null : value.getBytes("ISO-8859-1"));
    }

    public static <T> void set(Map<String, String> conf, String key, Codec<T> codec, T obj) throws IOException {
        String value = new String(codec.encode(obj), Charsets.UTF_8);
        LOG.trace("Serializing {} {}", key, value);
        conf.put(key, value);
    }

    public static <T> T get(Map<String, String> conf, String key, Codec<T> codec) throws IOException {
        String value = conf.get(key);
        LOG.trace("De-serializing {} {}", key, value);
        // Using Latin-1 encoding so that all bytes can be encoded as string. UTF-8 has some invalid bytes that will get
        // skipped.
        return codec.decode(value == null ? null : value.getBytes("ISO-8859-1"));
    }

    /**
     * Creates a new map containing all key-value pairs in the given {@link Configuration}.
     */
    public static Map<String, String> toMap(Configuration conf) {
        Map<String, String> map = new HashMap<>();
        for (Map.Entry<String, String> entry : conf) {
            map.put(entry.getKey(), entry.getValue());
        }
        return map;
    }

    /**
     * Sets all key-value pairs from the given {@link Map} into the given {@link Configuration}.
     *
     * @return the {@link Configuration} instance provided
     */
    public static Configuration setAll(@Nullable Map<String, String> map, Configuration conf) {
        if (map == null) {
            return conf;
        }
        for (Map.Entry<String, String> entry : map.entrySet()) {
            conf.set(entry.getKey(), entry.getValue());
        }
        return conf;
    }

    /**
     * Prefixes the specified configurations with the given prefix, and sets them onto the job's configuration.
     *
     * @param conf the Configuration object on which the configurations will be set on
     * @param confKeyPrefix the String to prefix the keys of the configuration
     * @param namedConf the configuration values to be set
     */
    public static void setNamedConfigurations(Configuration conf, String confKeyPrefix,
            Map<String, String> namedConf) {
        for (Map.Entry<String, String> entry : namedConf.entrySet()) {
            conf.set(confKeyPrefix + entry.getKey(), entry.getValue());
        }
    }

    /**
     * Retrieves all configurations that are prefixed with a particular prefix.
     *
     * @see {@link #setNamedConfigurations(Configuration, String, Map)}.
     *
     * @param conf the Configuration from which to get the configurations
     * @param confKeyPrefix the prefix to search for in the keys
     * @return a map of key-value pairs, representing the requested configurations, after removing the prefix
     */
    public static Map<String, String> getNamedConfigurations(Configuration conf, String confKeyPrefix) {
        Map<String, String> namedConf = new HashMap<>();
        int prefixLength = confKeyPrefix.length();
        // since its a regex match, we want to look for the character '.', and not match any character
        confKeyPrefix = confKeyPrefix.replace(".", "\\.");
        Map<String, String> properties = conf.getValByRegex("^" + confKeyPrefix + ".*");
        for (Map.Entry<String, String> entry : properties.entrySet()) {
            namedConf.put(entry.getKey().substring(prefixLength), entry.getValue());
        }
        return namedConf;
    }

    private ConfigurationUtil() {
        // no-op
    }
}