org.apache.wicket.util.lang.Args.java Source code

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Here is the source code for org.apache.wicket.util.lang.Args.java

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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.wicket.util.lang;

import java.util.Collection;

import org.apache.wicket.util.string.Strings;

/**
 * Class with methods for asserting conditions on arguments. 
 */
public class Args {
    /**
     * Checks argument is not null
     * 
     * @param <T>
     * @param argument
     * @param name
     * @return The 'argument' parameter
     * @throws IllegalArgumentException
     */
    public static <T> T notNull(final T argument, final String name) {
        if (argument == null) {
            throw new IllegalArgumentException("Argument '" + name + "' may not be null.");
        }
        return argument;
    }

    /**
     * Checks argument is not empty (not null and has a non-whitespace character)
     * 
     * @param <T>
     *            the type of the argument to check for emptiness
     * 
     * @param argument
     *            the argument to check for emptiness
     * @param name
     *            the name to use in the error message
     * @return The {@code argument} parameter if not empty
     * @throws IllegalArgumentException
     *             when the passed {@code argument} is empty
     */
    public static <T extends CharSequence> T notEmpty(final T argument, final String name) {
        if (Strings.isEmpty(argument)) {
            throw new IllegalArgumentException("Argument '" + name + "' may not be null or empty.");
        }
        return argument;
    }

    /**
     * 
     * Checks argument is not null or empty
     * 
     * @param collection
     * @param message
     * @param params
     * @return the {code collection}
     * @throws IllegalArgumentException
     *             if the passed collection is either null or empty
     */
    public static <T extends Collection<?>> T notEmpty(final T collection, final String message,
            final Object... params) {
        if (collection == null || collection.isEmpty()) {
            throw new IllegalArgumentException(Args.format(message, params));
        }
        return collection;
    }

    /**
     * Checks argument is not null or empty
     * 
     * @param collection
     * @param name
     * @return the {code collection}
     * @throws IllegalArgumentException
     *             if the passed collection is either null or empty
     */
    public static <T extends Collection<?>> T notEmpty(final T collection, final String name) {
        return notEmpty(collection, "Collection '%s' may not be null or empty.", name);
    }

    /**
     * Checks if argument is within a range
     * 
     * @param <T>
     * @param min
     * @param max
     * @param value
     * @param name
     * @return the {code value}
     * @throws IllegalArgumentException
     */
    public static <T extends Comparable<? super T>> T withinRange(final T min, final T max, final T value,
            final String name) {
        notNull(min, name);
        notNull(max, name);
        if ((value.compareTo(min) < 0) || (value.compareTo(max) > 0)) {
            throw new IllegalArgumentException(String
                    .format("Argument '%s' must have a value within [%s,%s], but was %s", name, min, max, value));
        }
        return value;
    }

    /**
     * Check if argument is true
     * 
     * @param argument
     * @param msg
     * @param params
     * @return argument
     */
    public static boolean isTrue(final boolean argument, final String msg, final Object... params) {
        if (argument == false) {
            throw new IllegalArgumentException(format(msg, params));
        }
        return argument;
    }

    /**
     * Check if argument is false
     * 
     * @param argument
     * @param msg
     * @param params
     * @return argument
     */
    public static boolean isFalse(final boolean argument, final String msg, final Object... params) {
        if (argument == true) {
            throw new IllegalArgumentException(format(msg, params));
        }
        return argument;
    }

    /**
     * Format the message. Allow for "{}" as well as %s etc. (see Formatter).
     * 
     * @param msg
     * @param params
     * @return formatted message
     */
    static String format(String msg, final Object... params) {
        msg = msg.replaceAll("\\{\\}", "%s");
        return String.format(msg, params);
    }
}