001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.scxml.model;
018    
019    import java.util.LinkedHashSet;
020    import java.util.Set;
021    
022    /**
023     * The class in this SCXML object model that corresponds to the
024     * <parallel> SCXML element, which is a wrapper element to
025     * encapsulate parallel state machines. For the <parallel> element
026     * to be useful, each of its <state> substates must itself be
027     * complex, that is, one with either <state> or <parallel>
028     * children.
029     *
030     */
031    public class Parallel extends TransitionTarget {
032    
033        /**
034         * Serial version UID.
035         */
036        private static final long serialVersionUID = 2L;
037    
038        /**
039         * The set of parallel state machines contained in this <parallel>.
040         */
041        private Set children;
042    
043        /**
044         * Constructor.
045         */
046        public Parallel() {
047            this.children = new LinkedHashSet();
048        }
049    
050        /**
051         * Get the set of parallel state machines contained in this Parallel.
052         *
053         * @return Returns the state.
054         *
055         * @deprecated Use getChildren() instead.
056         */
057        public final Set getStates() {
058            return children;
059        }
060    
061        /**
062         * Add a State to the list of parallel state machines contained
063         * in this Parallel.
064         *
065         * @param state The state to add.
066         *
067         * @deprecated Use addChild(TransitionTarget) instead.
068         */
069        public final void addState(final State state) {
070            if (state != null) {
071                this.children.add(state);
072                state.setParent(this);
073            }
074        }
075    
076        /**
077         * Get the set of child transition targets (may be empty).
078         *
079         * @return Set Returns the children.
080         *
081         * @since 0.7
082         */
083        public final Set getChildren() {
084            return children;
085        }
086    
087        /**
088         * Add a child.
089         *
090         * @param tt A child transition target.
091         *
092         * @since 0.7
093         */
094        public final void addChild(final TransitionTarget tt) {
095            // TODO: State is a sufficient enough type for the parameter
096            this.children.add(tt);
097            tt.setParent(this);
098        }
099    
100    }
101