// /////////////////////////////////////////////////////////
// This file is part of Propel.
//
// Propel is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Propel is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Propel. If not, see <http://www.gnu.org/licenses/>.
// /////////////////////////////////////////////////////////
// Authored by: Nikolaos Tountas -> salam.kaser-at-gmail.com
// /////////////////////////////////////////////////////////
package propel.core.functional.projections;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import lombok.Actions.Action0;
import lombok.Actions.Action1;
import lombok.SneakyThrows;
import lombok.Validate;
import lombok.Validate.NotNull;
import lombok.val;
import propel.core.utils.ReflectionUtils;
/**
* Some common, re-usable dynamic method invocation projections
*/
public final class InvokeDynamic
{
/**
* A no-argument action which invokes the method name specified on the given object.
*
* @throws NullPointerException An argument is null
* @throws IllegalArgumentException There is no method found having the specified method name on the given object, or more than one
* methods have the specified name
*/
@Validate
public static Action0 invokeMethodWithNoArgsOn(@NotNull final Object obj, @NotNull final String methodName)
{
return new Action0() {
private final Method method;
// initialiser block
{
method = getSingleMethodIfExists(obj, methodName);
}
@SneakyThrows
public void apply()
{
try
{
method.invoke(obj, (Object[]) null);
}
catch(InvocationTargetException e)
{
// get rid of wrapper exception
throw e.getCause();
}
}
};
}
/**
* Returns a one-argument action which invokes the method name specified on the given object, passing the function argument to the invoked
* method.
*
* @throws NullPointerException An argument is null
* @throws IllegalArgumentException There is no method found having the specified method name on the given object, or more than one
* methods have the specified name
*/
@Validate
public static Action1<Object> invokeMethodWithOneArgOn(@NotNull final Object obj, @NotNull final String methodName)
{
return new Action1<Object>() {
private final Method method;
// initialiser block
{
method = getSingleMethodIfExists(obj, methodName);
}
@SneakyThrows
public void apply(Object arg)
{
try
{
method.invoke(obj, arg);
}
catch(InvocationTargetException e)
{
// get rid of wrapper exception
throw e.getCause();
}
}
};
}
/**
* Returns a one-argument action which invokes the no-arg method on this argument
*
* @throws NullPointerException An argument is null
* @throws IllegalArgumentException There is no method found having the specified method name on the given object, or more than one
* methods have the specified name
*/
@Validate
public static Action1<Object> invokeMethod(@NotNull final String methodName)
{
return invokeMethod(methodName, null);
}
/**
* Returns a one-argument action which invokes the one-arg method on this argument
*
* @throws NullPointerException An argument is null
* @throws IllegalArgumentException There is no method found having the specified method name on the given object, or more than one
* methods have the specified name
*/
@Validate
public static Action1<Object> invokeMethod(@NotNull final String methodName, final Object[] obj)
{
return new Action1<Object>() {
@SneakyThrows
public void apply(Object arg)
{
try
{
Method method = getSingleMethodIfExists(arg, methodName);
method.invoke(arg, obj);
}
catch(InvocationTargetException e)
{
// get rid of wrapper exception
throw e.getCause();
}
}
};
}
static Method getSingleMethodIfExists(final Object obj, final String methodName)
{
val methods = ReflectionUtils.getMethods(obj.getClass(), methodName, false);
if (methods.length > 1)
throw new IllegalArgumentException("Found multiple method overloads for " + obj.getClass() + "." + methodName);
if (methods.length <= 0)
throw new IllegalArgumentException("Could not find method " + obj.getClass() + "." + methodName);
return methods[0];
}
private InvokeDynamic()
{
}
}