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

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/*******************************************************************************
 * 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.Map;

import org.apache.commons.lang.ObjectUtils;

import com.google.common.collect.Maps;

public class TransitionParameterSet {

    public static final TransitionParameterSet EMPTY = new TransitionParameterSet();

    public static final TransitionParameterSet create() {
        return new TransitionParameterSet();
    }

    private final Map<String, TransitionParameter> parameters = Maps.newHashMap();

    private TransitionParameterSet() {
    }

    public TransitionParameterSet clear() {
        parameters.clear();
        return this;
    }

    public <T> T get(final Class<T> clazz, String name) {
        if (parameters.containsKey(name)) {
            Object value = parameters.get(name).getValue();
            if (value == null) {
                return null;
            }
            try {
                return clazz.cast(value);
            } catch (ClassCastException e) {
                throw new WorkflowExecutionException("Cannot cast value of transition parameter [" + name
                        + "] from type [" + value.getClass().getName() + "] to type [" + clazz.getName() + "]");
            }
        } else {
            return null;
        }
    }

    public <T> TransitionParameterSet set(String name, T value) {
        if (!parameters.containsKey(name) || !ObjectUtils.equals(parameters.get(name).getValue(), value)) {
            parameters.put(name, new TransitionParameter(name, value));
        }
        return this;
    }
}