DockerApiVersionPathPrefixProvider.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.plugin.docker.client;

import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import com.google.inject.name.Named;

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

import static java.lang.String.format;

/**
 * This class provides docker api version path prefix that should be used in Docker API calls. See {@link DockerConnector}.
 *
 * @author Alexander Andrienko
 */
@Singleton
public class DockerApiVersionPathPrefixProvider implements Provider<String> {

    //Supports docker api version value in format: '1', '1.18' etc.
    private static final Pattern VERSION_API_PATTERN    = Pattern.compile("([0-9]+)(\\.[0-9]+)?");
    private static final String  VALID_PROPERTY_EXAMPLE =
            "Valid docker api version contains digits which can be separated by symbol '.'. For example: '1', '1.18'";

    public static final String MACHINE_DOCKER_API_VERSION = "che.docker.api";

    private final String apiVersionPrefixPath;

    @Inject
    public DockerApiVersionPathPrefixProvider(@Named(MACHINE_DOCKER_API_VERSION) String apiVersion) {
        if (apiVersion.isEmpty()) {
            this.apiVersionPrefixPath = "";
            return;
        }
        Matcher matcher = VERSION_API_PATTERN.matcher(apiVersion);
        if (matcher.matches()) {
            this.apiVersionPrefixPath = "/v" + apiVersion;
            return;
        }
        throw new IllegalArgumentException(format("Invalid property format: '%s'. %s", MACHINE_DOCKER_API_VERSION, VALID_PROPERTY_EXAMPLE));
    }

    @Override
    public String get() {
        return apiVersionPrefixPath;
    }
}