TransitionSet.java :  » J2EE » spring-ide_2.3.0 » org » springframework » webflow » engine » Java Open Source

/*
 * Copyright 2004-2008 the original author or authors.
 *
 * 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 org.springframework.webflow.engine;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.springframework.core.style.StylerUtils;
import org.springframework.webflow.core.collection.CollectionUtils;
import org.springframework.webflow.execution.RequestContext;

/**
 * A typed set of transitions for use internally by artifacts that can apply transition execution logic.
 * 
 * @see TransitionableState#getTransitionSet()
 * @see Flow#getGlobalTransitionSet()
 * 
 * @author Keith Donald
 */
public class TransitionSet {

  /**
   * The set of transitions.
   */
  private List transitions = new LinkedList();

  /**
   * Add a transition to this set.
   * @param transition the transition to add
   * @return true if this set's contents changed as a result of the add operation
   */
  public boolean add(Transition transition) {
    if (contains(transition)) {
      return false;
    }
    return transitions.add(transition);
  }

  /**
   * Add a collection of transition instances to this set.
   * @param transitions the transitions to add
   * @return true if this set's contents changed as a result of the add operation
   */
  public boolean addAll(Transition[] transitions) {
    return CollectionUtils.addAllNoDuplicates(this.transitions, transitions);
  }

  /**
   * Tests if this transition is in this set.
   * @param transition the transition
   * @return true if the transition is contained in this set, false otherwise
   */
  public boolean contains(Transition transition) {
    return transitions.contains(transition);
  }

  /**
   * Remove the transition instance from this set.
   * @param transition the transition to remove
   * @return true if this list's contents changed as a result of the remove operation
   */
  public boolean remove(Transition transition) {
    return transitions.remove(transition);
  }

  /**
   * Returns the size of this transition set.
   * @return the exception handler set size
   */
  public int size() {
    return transitions.size();
  }

  /**
   * Returns an iterator over this transition set.
   * @return an iterator
   */
  public Iterator iterator() {
    return transitions.iterator();
  }

  /**
   * Convert this set to a typed transition array.
   * @return the transition set as a typed array
   */
  public Transition[] toArray() {
    return (Transition[]) transitions.toArray(new Transition[transitions.size()]);
  }

  /**
   * Returns a list of the supported transitional criteria used to match transitions in this state.
   * @return the list of transitional criteria
   */
  public TransitionCriteria[] getTransitionCriterias() {
    TransitionCriteria[] criterias = new TransitionCriteria[transitions.size()];
    int i = 0;
    Iterator it = transitions.iterator();
    while (it.hasNext()) {
      criterias[i++] = ((Transition) it.next()).getMatchingCriteria();
    }
    return criterias;
  }

  /**
   * Gets a transition for given flow execution request context. The first matching transition will be returned.
   * @param context a flow execution context
   * @return the transition, or null if no transition matches
   */
  public Transition getTransition(RequestContext context) {
    Iterator it = transitions.iterator();
    while (it.hasNext()) {
      Transition transition = (Transition) it.next();
      if (transition.matches(context)) {
        return transition;
      }
    }
    return null;
  }

  /**
   * Returns whether or not this list has a transition that will fire for given flow execution request context.
   * @param context a flow execution context
   */
  public boolean hasMatchingTransition(RequestContext context) {
    return getTransition(context) != null;
  }

  public String toString() {
    return StylerUtils.style(transitions);
  }
}