/*
 * The MIT License
 *
 * Copyright (c) 2004-2009, Sun Microsystems, Inc., Tom Huybrechts
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package hudson.model;

import hudson.EnvVars;
import hudson.Launcher;
import hudson.model.listeners.RunListener;
import hudson.slaves.NodeProperty;
import hudson.tasks.BuildWrapper;
import hudson.tasks.Builder;
import java.io.IOException;
import java.util.Map;

/**
 * Represents some resources that are set up for the duration of a build
 * to be torn down when the build is over.
 *
 * <p>
 * This is often used to run a parallel server necessary during a build,
 * such as an application server, a database reserved for the build,
 * X server for performing UI tests, etc.
 *
 * <p>
 * By having a plugin that does this, instead of asking each build script to do this,
 * we can simplify the build script. {@link Environment} abstraction also gives
 * you guaranteed "tear down" phase, so that such resource won't keep running forever.
 *
 * @since 1.286
 * @see BuildWrapper
 * @see NodeProperty
 * @see RunListener#setUpEnvironment(AbstractBuild, Launcher, BuildListener)
 */
public abstract class Environment {
    /**
     * Adds environmental variables for the builds to the given map.
     *
     * <p>
     * If the {@link Environment} object wants to pass in information to the
     * build that runs, it can do so by exporting additional environment
     * variables to the map.
     *
     * <p>
     * When this method is invoked, the map already contains the current
     * "planned export" list.
     *
     * @param env
     *          never null. This really should have been typed as {@link EnvVars}
     *          but by the time we realized it it was too late.
     */
    public void buildEnvVars(Map<String, String> env) {
        // no-op by default
    }

    /**
     * Runs after the {@link Builder} completes, and performs a tear down.
     *
     * <p>
     * This method is invoked even when the build failed, so that the clean up
     * operation can be performed regardless of the build result (for example,
     * you'll want to stop application server even if a build fails.)
     *
     * @param build
     *            The same {@link Build} object given to the set up method.
     * @param listener
     *            The same {@link BuildListener} object given to the set up
     *            method.
     * @return true if the build can continue, false if there was an error and
     *         the build needs to be failed.
     * @throws IOException
     *             terminates the build abnormally. Jenkins will handle the
     *             exception and reports a nice error message.
     */
    public boolean tearDown(AbstractBuild build, BuildListener listener)
            throws IOException, InterruptedException {
        return true;
    }

    /**
     * Creates {@link Environment} implementation that just sets the variables as given in the parameter.
     */
    public static Environment create(final EnvVars envVars) {
        return new Environment() {
            @Override
            public void buildEnvVars(Map<String, String> env) {
                env.putAll(envVars);
            }
        };
    }

}
