Java tutorial
/* * 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 <a href="mailto:philipp DOT erlacher AT gmail DOT com">Philipp Erlacher</a> * */ 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; } }