source: branches/autoquest-core-tasktrees-alignment/src/main/java/de/ugoe/cs/autoquest/tasktrees/taskequality/TaskAndSelectionComparisonRule.java

//   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.taskequality;

import java.util.List;

import de.ugoe.cs.autoquest.tasktrees.treeifc.ISelection;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ISelectionInstance;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITask;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskInstance;

// TODO: Auto-generated Javadoc
/**
 * <p>
 * This class is capable of comparing any task which is not a selection with a
 * selection. This is needed, because selections may contain exactly that task.
 * Therefore, if this task is selected out of a selection the selection is equal
 * to the task itself. The rule returns lexically equal, if the selection
 * contains a lexically equal task. The same applies for syntactical and
 * semantical equality.
 * </p>
 * 
 * @author Patrick Harms
 */
public class TaskAndSelectionComparisonRule implements TaskComparisonRule {

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areLexicallyEqual(ITask, ITask)
         */
        @Override
        public boolean areLexicallyEqual(ITask task1, ITask task2) {
                final TaskEquality equality = getEquality(task1, task2,
                                TaskEquality.LEXICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.LEXICALLY_EQUAL));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areLexicallyEqual(ITaskInstance, ITaskInstance)
         */
        @Override
        public boolean areLexicallyEqual(ITaskInstance instance1,
                        ITaskInstance instance2) {
                final TaskEquality equality = getEquality(instance1, instance2,
                                TaskEquality.LEXICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.LEXICALLY_EQUAL));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areSemanticallyEqual(ITask, ITask)
         */
        @Override
        public boolean areSemanticallyEqual(ITask task1, ITask task2) {
                final TaskEquality equality = getEquality(task1, task2,
                                TaskEquality.SEMANTICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.SEMANTICALLY_EQUAL));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areSemanticallyEqual(ITaskInstance,
         * ITaskInstance)
         */
        @Override
        public boolean areSemanticallyEqual(ITaskInstance instance1,
                        ITaskInstance instance2) {
                final TaskEquality equality = getEquality(instance1, instance2,
                                TaskEquality.SEMANTICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.SEMANTICALLY_EQUAL));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areSyntacticallyEqual(ITask, ITask)
         */
        @Override
        public boolean areSyntacticallyEqual(ITask task1, ITask task2) {
                final TaskEquality equality = getEquality(task1, task2,
                                TaskEquality.SYNTACTICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.SYNTACTICALLY_EQUAL));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#areSyntacticallyEqual(ITaskInstance,
         * ITaskInstance)
         */
        @Override
        public boolean areSyntacticallyEqual(ITaskInstance instance1,
                        ITaskInstance instance2) {
                final TaskEquality equality = getEquality(instance1, instance2,
                                TaskEquality.SYNTACTICALLY_EQUAL);
                return (equality != null)
                                && (equality.isAtLeast(TaskEquality.SYNTACTICALLY_EQUAL));
        }

        /**
         * <p>
         * used to to call the task equality rule manager for the comparison of the
         * two provided children. If no required equality level is provided, than
         * the most concrete equality is returned. Otherwise, the required equality
         * is returned as long as the children are equal on that level.
         * </p>
         * 
         * @param child1
         *            the first task to be compared
         * @param child2
         *            the second task to be compared
         * @param requiredEqualityLevel
         *            the equality level to be checked for
         * 
         * @return the determined equality
         */
        private TaskEquality callRuleManager(ITask child1, ITask child2,
                        TaskEquality requiredEqualityLevel) {
                if (requiredEqualityLevel == null) {
                        return TaskEqualityRuleManager.getInstance()
                                        .compare(child1, child2);
                } else if (TaskEqualityRuleManager.getInstance().areAtLeastEqual(
                                child1, child2, requiredEqualityLevel)) {
                        return requiredEqualityLevel;
                } else {
                        return TaskEquality.UNEQUAL;
                }
        }

        /**
         * <p>
         * used to to call the task equality rule manager for the comparison of the
         * two provided children. If no required equality level is provided, than
         * the most concrete equality is returned. Otherwise, the required equality
         * is returned as long as the children are equal on that level.
         * </p>
         * 
         * @param taskInstance1
         *            the first task instance to be compared
         * @param taskInstance2
         *            the second task instance to be compared
         * @param requiredEqualityLevel
         *            the equality level to be checked for
         * 
         * @return the determined equality
         */
        private TaskEquality callRuleManager(ITaskInstance taskInstance1,
                        ITaskInstance taskInstance2, TaskEquality requiredEqualityLevel) {
                if (requiredEqualityLevel == null) {
                        return TaskEqualityRuleManager.getInstance().compare(taskInstance1,
                                        taskInstance2);
                } else if (TaskEqualityRuleManager.getInstance().areAtLeastEqual(
                                taskInstance1, taskInstance2, requiredEqualityLevel)) {
                        return requiredEqualityLevel;
                } else {
                        return TaskEquality.UNEQUAL;
                }
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#compare(ITask, ITask)
         */
        @Override
        public TaskEquality compare(ITask task1, ITask task2) {
                return getEquality(task1, task2, null);
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#compare(ITaskInstance, ITaskInstance)
         */
        @Override
        public TaskEquality compare(ITaskInstance instance1, ITaskInstance instance2) {
                return getEquality(instance1, instance2, null);
        }

        /**
         * <p>
         * compares two tasks with each other checking for the provided required
         * level of equality. One of the tasks must be a selection, the other one
         * not. If this is not the case, the method returns null. The returned
         * equality level is at most lexical equality as the selection can not be
         * identical to something not being a selection.
         * </p>
         * 
         * @param task1
         *            the first task to be compared
         * @param task2
         *            the second task to be compared
         * @param requiredEqualityLevel
         *            the equality level to be checked for
         * 
         * @return the determined equality.
         */
        private TaskEquality getEquality(ITask task1, ITask task2,
                        TaskEquality requiredEqualityLevel) {
                ISelection selection = null;
                ITask task = null;

                if (task1 instanceof ISelection) {
                        if (task2 instanceof ISelection) {
                                // the rule is not responsible for two selections
                                return null;
                        }

                        selection = (ISelection) task1;
                        task = task2;
                } else if (task2 instanceof ISelection) {
                        if (task1 instanceof ISelection) {
                                // the rule is not responsible for two selections
                                return null;
                        }

                        selection = (ISelection) task2;
                        task = task1;
                } else {
                        return null;
                }

                // now, that we found the selection and the task, lets compare the
                // children of the selection
                // with the task.
                final List<ITask> children = selection.getChildren();

                if (children.size() < 1) {
                        return null;
                }

                TaskEquality mostConcreteNodeEquality = null;

                for (final ITask child : children) {
                        final TaskEquality taskEquality = callRuleManager(child, task,
                                        requiredEqualityLevel);

                        if (taskEquality != TaskEquality.UNEQUAL) {
                                if (mostConcreteNodeEquality == null) {
                                        mostConcreteNodeEquality = taskEquality;
                                } else if (mostConcreteNodeEquality.isAtLeast(taskEquality)) {
                                        mostConcreteNodeEquality = taskEquality;

                                }

                                if ((requiredEqualityLevel != null)
                                                && (mostConcreteNodeEquality
                                                                .isAtLeast(requiredEqualityLevel))) {
                                        // if we found one child of the selection that is as equal
                                        // as required, then
                                        // we can consider the selection to be sufficiently equal to
                                        // the other task.
                                        // So we break up checking further children.
                                        break;
                                }
                        }
                }

                // although the subtask may be identical to the task, we can not return
                // identical, as
                // the selection is not identical to the task, but at most lexically
                // equal
                if (mostConcreteNodeEquality == TaskEquality.IDENTICAL) {
                        return TaskEquality.LEXICALLY_EQUAL;
                } else {
                        return mostConcreteNodeEquality;
                }

        }

        /**
         * <p>
         * compares two task instances with each other checking for the provided
         * required level of equality. One of the task instances must be a
         * selection, the other one not. If this is not the case, the method returns
         * null. The returned equality level is at most lexical equality as the
         * selection can not be identical to something not being a selection.
         * </p>
         * 
         * @param taskInstance1
         *            the first task instance to be compared
         * @param taskInstance2
         *            the second task instance to be compared
         * @param requiredEqualityLevel
         *            the equality level to be checked for
         * 
         * @return the determined equality.
         */
        private TaskEquality getEquality(ITaskInstance taskInstance1,
                        ITaskInstance taskInstance2, TaskEquality requiredEqualityLevel) {
                ISelectionInstance selection = null;
                ITaskInstance task = null;

                if (taskInstance1 instanceof ISelectionInstance) {
                        if (taskInstance2 instanceof ISelectionInstance) {
                                // the rule is not responsible for two selections
                                return null;
                        }

                        selection = (ISelectionInstance) taskInstance1;
                        task = taskInstance2;
                } else if (taskInstance2 instanceof ISelectionInstance) {
                        if (taskInstance1 instanceof ISelectionInstance) {
                                // the rule is not responsible for two selections
                                return null;
                        }

                        selection = (ISelectionInstance) taskInstance2;
                        task = taskInstance1;
                } else {
                        return null;
                }

                // now, that we found the selection and the task, lets compare the child
                // of the selection
                // with the task.
                final ITaskInstance child = selection.getChild();

                if (child == null) {
                        return null;
                }

                final TaskEquality taskEquality = callRuleManager(child, task,
                                requiredEqualityLevel);

                // although the subtask may be identical to the task, we can not return
                // identical, as
                // the selection is not identical to the task, but at most lexically
                // equal
                if (taskEquality == TaskEquality.IDENTICAL) {
                        return TaskEquality.LEXICALLY_EQUAL;
                } else {
                        return taskEquality;
                }

        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#isApplicable(ITask, ITask)
         */
        @Override
        public boolean isApplicable(ITask task1, ITask task2) {
                return ((task1 instanceof ISelection) && (!(task2 instanceof ISelection)))
                                || ((task2 instanceof ISelection) && (!(task1 instanceof ISelection)));
        }

        /*
         * (non-Javadoc)
         * 
         * @see TaskComparisonRule#isApplicable(ITaskInstance, ITaskInstance)
         */
        @Override
        public boolean isApplicable(ITaskInstance instance1, ITaskInstance instance2) {
                return isApplicable(instance1.getTask(), instance2.getTask());
        }
}