org.joda.convert.ReflectionStringConverter Maven / Gradle / Ivy
/*
* Copyright 2010-present Stephen Colebourne
*
* 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.joda.convert;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Conversion to and from a string using reflection.
*
* The toString method must meet the following signature:
* {@code String anyName()} on Class T.
*
* ReflectionStringConverter is abstract, but all known implementations are thread-safe and immutable.
*
* @param the type of the converter
*/
abstract class ReflectionStringConverter implements TypedStringConverter {
/** The converted class. */
private final Class cls;
/** Conversion to a string. */
private final Method toString;
/**
* Creates an instance using two methods.
* @param cls the class this converts for, not null
* @param toString the toString method, not null
* @throws RuntimeException (or subclass) if the method signatures are invalid
*/
ReflectionStringConverter(Class cls, Method toString) {
if (toString.getParameterTypes().length != 0) {
throw new IllegalStateException("ToString method must have no parameters: " + toString);
}
if (toString.getReturnType() != String.class) {
throw new IllegalStateException("ToString method must return a String: " + toString);
}
this.cls = cls;
this.toString = toString;
}
//-----------------------------------------------------------------------
/**
* Converts the object to a {@code String}.
* @param object the object to convert, not null
* @return the converted string, may be null but generally not
*/
@Override
public String convertToString(T object) {
try {
return (String) toString.invoke(object);
} catch (IllegalAccessException ex) {
throw new IllegalStateException("Method is not accessible: " + toString);
} catch (InvocationTargetException ex) {
if (ex.getCause() instanceof RuntimeException) {
throw (RuntimeException) ex.getCause();
}
throw new RuntimeException(ex.getMessage(), ex.getCause());
}
}
//-----------------------------------------------------------------------
@Override
public String toString() {
return "RefectionStringConverter[" + cls.getSimpleName() + "]";
}
}