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/*
* 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 org.apache.commons.collections.functors;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.Transformer;
/**
* Transformer implementation calls the transformer whose predicate returns true,
* like a switch statement.
*
* @since Commons Collections 3.0
* @version $Revision$ $Date$
*
* @author Stephen Colebourne
*
* @deprecated Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
*/
@Deprecated(since = "2021-04-30")
public class SwitchTransformer implements Transformer, Serializable {
/**
* Serial version UID
*/
private static final long serialVersionUID = -6404460890903469332L;
/**
* The tests to consider
*/
private final Predicate[] iPredicates;
/**
* The matching transformers to call
*/
private final Transformer[] iTransformers;
/**
* The default transformer to call if no tests match
*/
private final Transformer iDefault;
/**
* Factory method that performs validation and copies the parameter arrays.
*
* @param predicates array of predicates, cloned, no nulls
* @param transformers matching array of transformers, cloned, no nulls
* @param defaultTransformer the transformer to use if no match, null means return null
* @return the chained transformer
* @throws IllegalArgumentException if array is null
* @throws IllegalArgumentException if any element in the array is null
*/
public static Transformer getInstance(Predicate[] predicates, Transformer[] transformers, Transformer defaultTransformer) {
FunctorUtils.validate(predicates);
FunctorUtils.validate(transformers);
if (predicates.length != transformers.length) {
throw new IllegalArgumentException("The predicate and transformer arrays must be the same size");
}
if (predicates.length == 0) {
return (defaultTransformer == null ? ConstantTransformer.NULL_INSTANCE : defaultTransformer);
}
predicates = FunctorUtils.copy(predicates);
transformers = FunctorUtils.copy(transformers);
return new SwitchTransformer(predicates, transformers, defaultTransformer);
}
/**
* Create a new Transformer that calls one of the transformers depending
* on the predicates.
*
* The Map consists of Predicate keys and Transformer values. A transformer
* is called if its matching predicate returns true. Each predicate is evaluated
* until one returns true. If no predicates evaluate to true, the default
* transformer is called. The default transformer is set in the map with a
* null key. The ordering is that of the iterator() method on the entryset
* collection of the map.
*
* @param predicatesAndTransformers a map of predicates to transformers
* @return the switch transformer
* @throws IllegalArgumentException if the map is null
* @throws IllegalArgumentException if any transformer in the map is null
* @throws ClassCastException if the map elements are of the wrong type
*/
public static Transformer getInstance(Map predicatesAndTransformers) {
Transformer[] transformers = null;
Predicate[] preds = null;
if (predicatesAndTransformers == null) {
throw new IllegalArgumentException("The predicate and transformer map must not be null");
}
if (predicatesAndTransformers.size() == 0) {
return ConstantTransformer.NULL_INSTANCE;
}
// convert to array like this to guarantee iterator() ordering
Transformer defaultTransformer = (Transformer) predicatesAndTransformers.remove(null);
int size = predicatesAndTransformers.size();
if (size == 0) {
return (defaultTransformer == null ? ConstantTransformer.NULL_INSTANCE : defaultTransformer);
}
transformers = new Transformer[size];
preds = new Predicate[size];
int i = 0;
for (Iterator it = predicatesAndTransformers.entrySet().iterator(); it.hasNext(); ) {
Map.Entry entry = (Map.Entry) it.next();
preds[i] = (Predicate) entry.getKey();
transformers[i] = (Transformer) entry.getValue();
i++;
}
return new SwitchTransformer(preds, transformers, defaultTransformer);
}
/**
* Constructor that performs no validation.
* Use getInstance if you want that.
*
* @param predicates array of predicates, not cloned, no nulls
* @param transformers matching array of transformers, not cloned, no nulls
* @param defaultTransformer the transformer to use if no match, null means return null
*/
public SwitchTransformer(Predicate[] predicates, Transformer[] transformers, Transformer defaultTransformer) {
super();
iPredicates = predicates;
iTransformers = transformers;
iDefault = (defaultTransformer == null ? ConstantTransformer.NULL_INSTANCE : defaultTransformer);
}
/**
* Transforms the input to result by calling the transformer whose matching
* predicate returns true.
*
* @param input the input object to transform
* @return the transformed result
*/
public Object transform(Object input) {
for (int i = 0; i < iPredicates.length; i++) {
if (iPredicates[i].evaluate(input) == true) {
return iTransformers[i].transform(input);
}
}
return iDefault.transform(input);
}
/**
* Gets the predicates, do not modify the array.
*
* @return the predicates
* @since Commons Collections 3.1
*/
public Predicate[] getPredicates() {
return iPredicates;
}
/**
* Gets the transformers, do not modify the array.
*
* @return the transformers
* @since Commons Collections 3.1
*/
public Transformer[] getTransformers() {
return iTransformers;
}
/**
* Gets the default transformer.
*
* @return the default transformer
* @since Commons Collections 3.1
*/
public Transformer getDefaultTransformer() {
return iDefault;
}
}