org.exolab.castor.xml.parsing.primitive.objects.PrimitiveEnum Maven / Gradle / Ivy

/*
 * Copyright 2005 Philipp Erlacher
 *
 * 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.exolab.castor.xml.parsing.primitive.objects;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.commons.lang3.StringUtils;

/**
 * This class is part of the command pattern implementation to instantiate an object. It is used as
 * a command by the command invoker {@link PrimitiveObject}.
 * 
 * @author Philipp Erlacher
 * 
 */
class PrimitiveEnum extends PrimitiveObject {

  @Override
  public Object getObject(Class type, String value) {
    if (StringUtils.isEmpty(value)) {
      return null;
    }

    // discover the fromValue Method
    try {
      Method valueOfMethod = type.getMethod("fromValue", new Class[] {String.class});
      return valueOfMethod.invoke(null, new Object[] {value});

    } catch (NoSuchMethodException e) {
      // do nothing, check valueOf method
    } catch (IllegalArgumentException e) {
      throw new IllegalStateException(e.toString());
    } catch (IllegalAccessException e) {
      throw new IllegalStateException(e.toString());
    } catch (InvocationTargetException e) {
      if (e.getTargetException() instanceof RuntimeException) {
        throw (RuntimeException) e.getTargetException();
      }
    }

    // backwards compability, check valueOf method to support
    // "simple" enums without value object
    try {
      Method valueOfMethod = type.getMethod("valueOf", new Class[] {String.class});
      return valueOfMethod.invoke(null, new Object[] {value});

    } catch (IllegalAccessException e) {
      throw new IllegalStateException(e.toString());
    } catch (InvocationTargetException e) {
      if (e.getTargetException() instanceof RuntimeException) {
        throw (RuntimeException) e.getTargetException();
      }
    } catch (NoSuchMethodException e) {
      String err = type.getName() + " does not contain the required method: public static "
          + type.getName() + " valueOf(String);";
      throw new IllegalArgumentException(err);
    }

    return value;
  }

}