Environments.java

/*
 * Copyright (c) 2013-2017 Cinchapi 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 com.cinchapi.concourse.util;

import static com.cinchapi.concourse.server.GlobalState.DEFAULT_ENVIRONMENT;

import java.util.Iterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.cinchapi.concourse.server.GlobalState;
import com.cinchapi.concourse.server.io.FileSystem;
import com.cinchapi.concourse.util.TSets;
import com.google.common.base.Strings;

/**
 * Utility methods related to Environments.
 * 
 * @author Jeff Nelson
 */
public final class Environments {

    /**
     * The pattern that is used for sanitizing the environment. We compile it
     * statically so that we can avoid the overhead of doing it for every
     * sanitization request.
     */
    private static final Pattern SANITIZER = Pattern.compile("[^A-Za-z0-9_]");

    /**
     * Ensure that we return the correct environment with
     * alphanumeric-char name for the specified {@code env}.
     * e.g. if {@code env} is null or empty then return the
     * {@link GlobalState#DEFAULT_ENVIRONMENT}.
     * 
     * @param env
     * @return the environment name
     */
    public static String sanitize(String env) {
        env = Strings.isNullOrEmpty(env) ? DEFAULT_ENVIRONMENT : env;
        Matcher matcher = SANITIZER.matcher(env);
        env = matcher.replaceAll(""); // ConcourseServer checks to make sure
                                      // sanitizing the default environment
                                      // won't turn it into an empty string
        return env;
    }

    /**
     * Return an iterator over all of the environments.
     * 
     * @param bufferStore - absolute path to location of buffer files
     * @param dbStore - absolute path to location of data files
     * @return the iterator
     */
    public static Iterator<String> iterator(String bufferStore, String dbStore) {
        return TSets.intersection(FileSystem.getSubDirs(bufferStore),
                FileSystem.getSubDirs(dbStore)).iterator();
    }

    private Environments() {/* noop */}

}