com.shigengyu.hyperion.core.TransitionConditionSet.java Source code

Introduction

Here is the source code for com.shigengyu.hyperion.core.TransitionConditionSet.java

Source

/*******************************************************************************
 * Copyright 2013-2014 Gengyu Shi
 *
 * 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 com.shigengyu.hyperion.core;

import java.util.Iterator;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;

import org.apache.commons.collections.CollectionUtils;
import org.springframework.stereotype.Service;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.shigengyu.hyperion.cache.TransitionConditionCache;

public class TransitionConditionSet implements Iterable<TransitionCondition> {

    @Service
    public static class TransitionConditionSetFactory {

        private static TransitionConditionSetFactory instance;

        @Resource
        private TransitionConditionCache transitionConditionCache;

        TransitionConditionSet create(Class<? extends TransitionCondition>[] conditionClasses) {

            ImmutableSet<TransitionCondition> conditions = ImmutableSet
                    .copyOf(Lists.transform(Lists.newArrayList(conditionClasses),
                            new Function<Class<? extends TransitionCondition>, TransitionCondition>() {

                                @Override
                                public TransitionCondition apply(Class<? extends TransitionCondition> input) {
                                    return transitionConditionCache.get(input);
                                }
                            }));

            return new TransitionConditionSet(conditions);
        }

        @PostConstruct
        private void initialize() {
            instance = this;
        }
    }

    public static TransitionConditionSet empty() {
        return new TransitionConditionSet();
    }

    public static TransitionConditionSet from(Class<? extends TransitionCondition>[] conditionClasses) {
        return TransitionConditionSetFactory.instance.create(conditionClasses);
    }

    private final ImmutableSet<TransitionCondition> conditions;

    private TransitionConditionSet() {
        conditions = ImmutableSet.of();
    }

    TransitionConditionSet(ImmutableSet<TransitionCondition> transitionConditions) {
        conditions = transitionConditions;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        TransitionConditionSet other = (TransitionConditionSet) obj;
        if (conditions == null) {
            if (other.conditions != null) {
                return false;
            }
        } else if (!CollectionUtils.isEqualCollection(conditions, other.conditions)) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int result = 0;
        for (TransitionCondition condition : conditions) {
            result ^= condition.hashCode();
        }
        return result;
    }

    @Override
    public Iterator<TransitionCondition> iterator() {
        return conditions.iterator();
    }
}