org.op4j.util.VarArgsUtil.java Source code

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Here is the source code for org.op4j.util.VarArgsUtil.java

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/*
 * =============================================================================
 * 
 *   Copyright (c) 2010, The OP4J team (http://www.op4j.org)
 * 
 *   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.op4j.util;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.Validate;

/**
 * 
 * @since 1.0
 * 
 * @author Daniel Fernández
 *
 */
public class VarArgsUtil {

    public static <T> List<T> asTargetList(final T... targets) {
        Validate.notNull(targets, "Targets cannot be null");
        Validate.isTrue(targets.length > 0, "Targets cannot be empty");
        return Arrays.asList(targets);
    }

    public static <T> List<T> asRequiredObjectList(final T... parameters) {
        Validate.notNull(parameters, "Parameters cannot be null");
        Validate.isTrue(parameters.length > 0, "Parameters cannot be empty");
        return Arrays.asList(parameters);
    }

    public static <T> Set<T> asRequiredObjectSet(final T... parameters) {
        Validate.notNull(parameters, "Parameters cannot be null");
        Validate.isTrue(parameters.length > 0, "Parameters cannot be empty");
        return new LinkedHashSet<T>(Arrays.asList(parameters));
    }

    public static List<Integer> asRequiredIntegerList(final int... parameters) {
        Validate.notNull(parameters, "Parameters cannot be null");
        Validate.isTrue(parameters.length > 0, "Parameters cannot be empty");
        return Arrays.asList(ArrayUtils.toObject(parameters));
    }

    public static Integer[] asRequiredIntegerArray(final int... parameters) {
        Validate.notNull(parameters, "Parameters cannot be null");
        Validate.isTrue(parameters.length > 0, "Paramters cannot be empty");
        return ArrayUtils.toObject(parameters);
    }

    public static <T> T[] asRequiredObjectArray(final T... parameters) {
        Validate.notNull(parameters, "Parameters cannot be null");
        Validate.isTrue(parameters.length > 0, "Paramters cannot be empty");
        return parameters;
    }

    @SuppressWarnings("unchecked")
    public static <T> List<T> asOptionalObjectList(final T... parameters) {
        final List<T> result = (List<T>) new ArrayList<Object>();
        if (parameters != null) {
            for (T parameter : parameters) {
                result.add(parameter);
            }
        } else {
            result.add(null);
        }
        return Collections.unmodifiableList(result);
    }

    @SuppressWarnings("unchecked")
    public static <T> T[] asOptionalObjectArray(final Class<T> arrayClass, final T... parameters) {
        if (parameters != null) {
            final T[] result = (T[]) Array.newInstance(arrayClass, parameters.length);
            for (int i = 0; i < parameters.length; i++) {
                result[i] = parameters[i];
            }
            return result;
        }
        final T[] result = (T[]) Array.newInstance(arrayClass, 1);
        result[0] = null;
        return result;
    }

    private VarArgsUtil() {
        super();
    }

}