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package org.graalvm.visualvm.jmx;

import java.util.Map;
import org.graalvm.visualvm.application.Application;
import org.graalvm.visualvm.core.datasource.Storage;

/**
 * Provider of the JMX environment for each JMX connection.
 *
 * @author Jiri Sedlacek
 */
public abstract class EnvironmentProvider {

    /**
     * Returns an unique String identifying the EnvironmentProvider. The return
     * value is used for persistency purposes and must be constant for providers
     * supporting persistent JMX connections. Default implementation returns
     * this.getClass().getName().
     *
     * @return unique String identifying the EnvironmentProvider
     */
    public String getId() { return getClass().getName(); }

    /**
     * Returns the JMX environment for the provided Application. The Storage
     * contains the data which may have been previously saved using the
     * saveEnvironment(Storage) method. Typically application.getStorage == storage.
     *
     * @param application Application for which to create the JMX environment
     * @param storage the Storage where the settings may have been previously saved using the saveEnvironment(Storage) method, typically it is application.getStorage()
     * @return JMX environment for the provided Application
     */
    public abstract Map<String, ?> getEnvironment(Application application, Storage storage);


    /**
     * Returns an unique identificator of the provided environment which helps
     * to differentiate JMX connections defined by the same connection string
     * but having different JMX environments. For example, the CredentialsProvider
     * returns the username if defined.
     *
     * Note: the provided Storage may be null which means that the provider
     * provides the environment for not persistent JMX connection.
     *
     * @param storage Storage or null if the JMX connection is not persistent
     * @return unique identificator of the provided environment
     */
    public String getEnvironmentId(Storage storage) { return ""; } // NOI18N
    
    /**
     * Gives the EnvironmentProvider a possibility to save it's settings into
     * a Storage. This method is called by the framework as soon as the Storage
     * is available. The provider may save the data to the provided Storage or
     * it can use it's own approach to persist the data.
     *
     * @param storage Storage to store the provider's settings
     */
    public void saveEnvironment(Storage storage) {}

    /**
     * Gives the EnvironmentProvider a possibility to load saved settings from
     * a Storage. This method is called by the framework as soon as the Storage
     * of a restored persistent JMX connection is available. The provider may
     * load the data from the provided Storage or it can use it's own approach
     * to retrieve the persisted data.
     *
     * Note: typically this method is not needed as the provider can access the
     * Storage directly in the getEnvironment(Application) method using
     * application.getStorage().
     *
     * @param storage Storage containing the provider's settings
     */
    public void loadEnvironment(Storage storage) {}

}
