Commons Collections example source code file (FunctorUtils.java)

This example Commons Collections source code file (FunctorUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Collections tags/keywords

closure, functorutils, illegalargumentexception, illegalargumentexception, iterator, predicate, predicate, the, the, transformer, transformer, util

The Commons Collections FunctorUtils.java source code

/*
 *  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.util.Collection;
import java.util.Iterator;

import org.apache.commons.collections.Closure;
import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.Transformer;

/**
 * Internal utilities for functors.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 *
 * @author Stephen Colebourne
 * @author Matt Benson
 */
class FunctorUtils {
    
    /**
     * Restricted constructor.
     */
    private FunctorUtils() {
        super();
    }
    
    /**
     * Clone the predicates to ensure that the internal reference can't be messed with.
     * 
     * @param predicates  the predicates to copy
     * @return the cloned predicates
     */
    static Predicate[] copy(Predicate[] predicates) {
        if (predicates == null) {
            return null;
        }
        return (Predicate[]) predicates.clone();
    }
    
    /**
     * Validate the predicates to ensure that all is well.
     * 
     * @param predicates  the predicates to validate
     */
    static void validate(Predicate[] predicates) {
        if (predicates == null) {
            throw new IllegalArgumentException("The predicate array must not be null");
        }
        for (int i = 0; i < predicates.length; i++) {
            if (predicates[i] == null) {
                throw new IllegalArgumentException("The predicate array must not contain a null predicate, index " + i + " was null");
            }
        }
    }
    
    /**
     * Validate the predicates to ensure that all is well.
     * 
     * @param predicates  the predicates to validate
     * @return predicate array
     */
    static Predicate[] validate(Collection predicates) {
        if (predicates == null) {
            throw new IllegalArgumentException("The predicate collection must not be null");
        }
        // convert to array like this to guarantee iterator() ordering
        Predicate[] preds = new Predicate[predicates.size()];
        int i = 0;
        for (Iterator it = predicates.iterator(); it.hasNext();) {
            preds[i] = (Predicate) it.next();
            if (preds[i] == null) {
                throw new IllegalArgumentException("The predicate collection must not contain a null predicate, index " + i + " was null");
            }
            i++;
        }
        return preds;
    }
    
    /**
     * Clone the closures to ensure that the internal reference can't be messed with.
     * 
     * @param closures  the closures to copy
     * @return the cloned closures
     */
    static Closure[] copy(Closure[] closures) {
        if (closures == null) {
            return null;
        }
        return (Closure[]) closures.clone();
    }
    
    /**
     * Validate the closures to ensure that all is well.
     * 
     * @param closures  the closures to validate
     */
    static void validate(Closure[] closures) {
        if (closures == null) {
            throw new IllegalArgumentException("The closure array must not be null");
        }
        for (int i = 0; i < closures.length; i++) {
            if (closures[i] == null) {
                throw new IllegalArgumentException("The closure array must not contain a null closure, index " + i + " was null");
            }
        }
    }

    /**
     * Copy method
     * 
     * @param transformers  the transformers to copy
     * @return a clone of the transformers
     */
    static Transformer[] copy(Transformer[] transformers) {
        if (transformers == null) {
            return null;
        }
        return (Transformer[]) transformers.clone();
    }
    
    /**
     * Validate method
     * 
     * @param transformers  the transformers to validate
     */
    static void validate(Transformer[] transformers) {
        if (transformers == null) {
            throw new IllegalArgumentException("The transformer array must not be null");
        }
        for (int i = 0; i < transformers.length; i++) {
            if (transformers[i] == null) {
                throw new IllegalArgumentException(
                    "The transformer array must not contain a null transformer, index " + i + " was null");
            }
        }
    }

}