source: branches/autoquest-core-tasktrees-alignment/src/main/java/de/ugoe/cs/autoquest/tasktrees/treeimpl/TaskInstance.java @ 1733

//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.tasktrees.treeimpl;

import de.ugoe.cs.autoquest.tasktrees.treeifc.ITask;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstance;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstanceVisitor;

/**
 * <p>
 * this is the default implementation of the interface {@link ITaskInstance}. It
 * does not do anything fancy except implementing the interface.
 * </p>
 * 
 * @author Patrick Harms
 */
class TaskInstance implements ITaskInstance {

        /**
         * <p>
         * creates a new id for a task instance using {@link #temporalId} by
         * incrementing it an returning its current value. Resets the counter if
         * {@link Integer.MAX_VALUE} is reached.
         * </p>
         * 
         * @return a new unique id for a task instance as long as
         *         {@link #temporalId} does not overflow
         */
        private static synchronized int getNewId() {
                if (temporalId == Integer.MAX_VALUE) {
                        temporalId = 0;
                }

                return temporalId++;
        }

        /**
         * <p>
         * default serial version UID
         * </p>
         */
        private static final long serialVersionUID = 1L;

        /**
         * <p>
         * used as a counter to generate new ids for each newly created task
         * instance. May overflow.
         * </p>
         */
        private static int temporalId = 0;

        /**
         * <p>
         * the task instantiated by this task instance
         * </p>
         */
        private ITask task;

        /**
         * <p>
         * the id of the task instance (unique throughout the system as long as
         * {@link #temporalId} does not overflow.
         * </p>
         */
        private final int id;

        /**
         * <p>
         * instantiated the task instance with the task that is instantiated by the
         * instance. It also assigns a unique id to the instance using
         * {@link #getNewId()}.
         * </p>
         */
        TaskInstance(ITask task) {
                this.task = task;
                id = getNewId();
        }

        /*
         * (non-Javadoc)
         * 
         * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstance#accept(
         * ITaskInstanceVisitor)
         */
        @Override
        public void accept(ITaskInstanceVisitor visitor) {
                visitor.visit(this);
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#clone()
         */
        @Override
        public synchronized ITaskInstance clone() {
                TaskInstance clone = null;
                try {
                        clone = (TaskInstance) super.clone();
                } catch (final CloneNotSupportedException e) {
                        // this should never happen. Therefore simply dump the exception
                        e.printStackTrace();
                }

                return clone;
        }

        /*
         * (non-Javadoc)
         * 
         * @see
         * de.ugoe.cs.autoquest.tasktrees.treeifc.TaskTreeNode#equals(TaskTreeNode)
         */
        @Override
        public boolean equals(ITaskInstance taskInstance) {
                // task instances are only equal if they are identical or if they have
                // the same id
                // (may happen, if they are cloned)
                return (this == taskInstance)
                                || (this.hashCode() == taskInstance.hashCode());
        }

        /*
         * (non-Javadoc)
         * 
         * @see de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstance#getTask()
         */
        @Override
        public ITask getTask() {
                return task;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#hashCode()
         */
        @Override
        public synchronized int hashCode() {
                return id;
        }

        /**
         * <p>
         * used to update the task represented through this instance
         * </p>
         * 
         * @param task
         *            the task to set
         */
        void setTask(ITask task) {
                this.task = task;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#toString()
         */
        @Override
        public synchronized String toString() {
                final StringBuffer result = new StringBuffer();
                result.append(task.getType());
                result.append(" #");
                result.append(task.getId());

                if (task.getDescription() != null) {
                        result.append(" (");
                        result.append(task.getDescription());
                        result.append(')');
                }

                /*
                 * if (children != null) { result.append(", ");
                 * result.append(children.size()); result.append(" children"); }
                 */

                return result.toString();
        }

}