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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.feilong.lib.collection4.functors;
import java.io.Serializable;
import java.util.Collection;
import org.apache.commons.collections4.Transformer;
/**
* Transformer implementation that chains the specified transformers together.
*
* The input object is passed to the first transformer. The transformed result
* is passed to the second transformer and so on.
*
*
* @param
*
* @since 3.0
*/
public class ChainedTransformer implements Transformer,Serializable{
/** Serial version UID */
private static final long serialVersionUID = 3514945074733160196L;
/** The transformers to call in turn */
private final Transformer[] iTransformers;
/**
* Factory method that performs validation and copies the parameter array.
*
* @param
* the object type
* @param transformers
* the transformers to chain, copied, no nulls
* @return the chained
transformer
* @throws NullPointerException
* if the transformers array is null
* @throws NullPointerException
* if any transformer in the array is null
*/
public static Transformer chainedTransformer(final Transformer...transformers){
FunctorUtils.validate(transformers);
if (transformers.length == 0){
return NOPTransformer. nopTransformer();
}
return new ChainedTransformer<>(transformers);
}
/**
* Create a new Transformer that calls each transformer in turn, passing the
* result into the next transformer. The ordering is that of the iterator()
* method on the collection.
*
* @param
* the object type
* @param transformers
* a collection of transformers to chain
* @return the chained
transformer
* @throws NullPointerException
* if the transformers collection is null
* @throws NullPointerException
* if any transformer in the collection is null
*/
public static Transformer chainedTransformer(final Collection> transformers){
if (transformers == null){
throw new NullPointerException("Transformer collection must not be null");
}
if (transformers.size() == 0){
return NOPTransformer. nopTransformer();
}
// convert to array like this to guarantee iterator() ordering
final Transformer[] cmds = transformers.toArray(new Transformer[transformers.size()]);
FunctorUtils.validate(cmds);
return new ChainedTransformer<>(false, cmds);
}
/**
* Hidden constructor for the use by the static factory methods.
*
* @param clone
* if {@code true} the input argument will be cloned
* @param transformers
* the transformers to chain, no nulls
*/
private ChainedTransformer(final boolean clone, final Transformer[] transformers){
super();
iTransformers = clone ? FunctorUtils.copy(transformers) : transformers;
}
/**
* Constructor that performs no validation.
* Use chainedTransformer
if you want that.
*
* @param transformers
* the transformers to chain, copied, no nulls
*/
public ChainedTransformer(final Transformer...transformers){
this(true, transformers);
}
/**
* Transforms the input to result via each decorated transformer
*
* @param object
* the input object passed to the first transformer
* @return the transformed result
*/
@Override
public T transform(T object){
for (final Transformer iTransformer : iTransformers){
object = iTransformer.transform(object);
}
return object;
}
/**
* Gets the transformers.
*
* @return a copy of the transformers
* @since 3.1
*/
public Transformer[] getTransformers(){
return FunctorUtils. copy(iTransformers);
}
}