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/*******************************************************************************
 * Copyright 2016 Guy Davenport
 *
 * 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 uno.informatics.common;

public interface ProgressMonitor {
    /**
     * Notifies that the main task is beginning. This must only be called once
     * on a given progress monitor instance.
     * 
     * @param name
     *            the name (or description) of the main task
     * @param totalWork
     *            the total number of work units into which the main task is
     *            been subdivided. If the value is UNKNOWN the
     *            implementation is free to indicate progress in a way which
     *            doesn't require the total number of work units in advance.
     */
    public void beginTask(String name, int totalWork);

    /**
     * Notifies that the work is done; that is, either the main task is
     * completed or the user canceled it. This method may be called more than
     * once (implementations should be prepared to handle this case).
     */
    public void done();

    /**
     * Internal method to handle scaling correctly. This method must not be
     * called by a client. Clients should always use the method
     * worked(int).
     * 
     * @param work
     *            the amount of work done
     */
    public void internalWorked(double work);

    /**
     * Returns whether cancelation of current operation has been requested.
     * Long-running operations should poll to see if cancelation has been
     * requested.
     *
     * @return true if cancellation has been requested, and
     *         false otherwise
     * @see #setCanceled(boolean)
     */
    public boolean isCanceled();

    /**
     * Sets the cancel state to the given value.
     * 
     * @param value
     *            true indicates that cancelation has been
     *            requested (but not necessarily acknowledged);
     *            false clears this flag
     * @see #isCanceled()
     */
    public void setCanceled(boolean value);

    /**
     * Sets the task name to the given value. This method is used to restore the
     * task label after a nested operation was executed. Normally there is no
     * need for clients to call this method.
     *
     * @param name
     *            the name (or description) of the main task
     * @see #beginTask(java.lang.String, int)
     */
    public void setTaskName(String name);

    /**
     * Notifies that a subtask of the main task is beginning. Subtasks are
     * optional; the main task might not have subtasks.
     *
     * @param name
     *            the name (or description) of the subtask
     */
    public void subTask(String name);

    /**
     * Notifies that a given number of work unit of the main task has been
     * completed. Note that this amount represents an installment, as opposed to
     * a cumulative amount of work done to date.
     *
     * @param work
     *            a non-negative number of work units just completed
     */
    public void worked(int work);
}