org.metafacture.commons.Require Maven / Gradle / Ivy

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/*
 * Copyright 2016 Christoph Böhme
 *
 * 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.metafacture.commons;

/**
 * Defines static methods for method argument validation.
 *
 * @author Christoph Böhme
 *
 */
public final class Require {

    private Require() {
        // No instances allowed
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code object} is
     * {@literal null}.
     *
     * @param  type of the object passed as parameter
     * @param object reference to be checked
     * @return the {@code object}
     */
    public static  T notNull(final T object) {
        return notNull(object, "parameter must not be null");
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code object} is
     * {@literal null}.
     *
     * @param  type of the object passed as parameter
     * @param object reference to be checked
     * @param message exception message
     * @return the {@code object}
     */
    public static  T notNull(final T object, final String message) {
        if (object == null) {
            throw new IllegalArgumentException(message);
        }
        return object;
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code value} is negative.
     *
     * @param value the value to be checked
     * @return the {@code value}
     */
    public static int notNegative(final int value) {
        return notNegative(value, "parameter must not be negative");
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code value} is negative.
     *
     * @param value the value to be checked
     * @param message exception message
     * @return the {@code value}
     */
    public static int notNegative(final int value, final String message) {
        if (value < 0) {
            throw new IllegalArgumentException(message);
        }
        return value;
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code condition} is false.
     *
     * @param condition the condition to be checked
     */
    public static void that(final boolean condition) {
        that(condition, "parameter is not valid");
    }

    /**
     * Throws an {@link IllegalArgumentException} if {@code condition} is false.
     *
     * @param condition the condition to be checked
     * @param message exception message
     */
    public static void that(final boolean condition, final String message) {
        if (!condition) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Throws an {@link IndexOutOfBoundsException} if {@code index} is negative
     * or equal to or greater than {@code arrayLength}.
     *
     * @param index the index value to be checked
     * @param arrayLength the upper bound against which {@code index} is checked
     * @return the {@code index}
     */
    public static int validArrayIndex(final int index, final int arrayLength) {
        return validArrayIndex(index, arrayLength, "array index out of range");
    }

    /**
     * Throws an {@link IndexOutOfBoundsException} if {@code index} is negative
     * or equal to or greater than {@code arrayLength}.
     *
     * @param index the index value to be checked
     * @param arrayLength the upper bound against which {@code index} is checked
     * @param message exception message
     * @return the {@code index}
     */
    public static int validArrayIndex(final int index, final int arrayLength,
            final String message) {
        if (index < 0 || index >= arrayLength) {
            throw new IndexOutOfBoundsException(message);
        }
        return index;
    }

    /**
     * Throws an {@link IndexOutOfBoundsException} if {@code sliceFrom} or
     * {@code sliceLength} is negative or the sum of both is greater than
     * {@code arrayLength}. Note that this means that a slice of length zero
     * starting at array length is a valid slice.
     *
     * @param sliceFrom the start index of the slice to be checked
     * @param sliceLength the length of the slice to be checked
     * @param arrayLength the upper bound against which the slice is checked
     */
    public static void validArraySlice(final int sliceFrom,
            final int sliceLength, final int arrayLength) {
        validArraySlice(sliceFrom, sliceLength, arrayLength,
                "array slice out of range");
    }

    /**
     * Throws an {@link IndexOutOfBoundsException} if {@code sliceFrom} or
     * {@code sliceLength} is negative or the sum of both is greater than
     * {@code arrayLength}. Note that this means that a slice of length zero
     * starting at array length is a valid slice.
     *
     *
     * @param sliceFrom the start index of the slice to be checked
     * @param sliceLength the length of the slice to be checked
     * @param arrayLength the upper bound against which the slice is checked
     * @param message exception message
     */
    public static void validArraySlice(final int sliceFrom,
            final int sliceLength, final int arrayLength, final String message) {
        if (sliceFrom < 0 || sliceLength < 0) {
            throw new IndexOutOfBoundsException(message);
        }
        if (sliceFrom + sliceLength > arrayLength) {
            throw new IndexOutOfBoundsException(message);
        }
    }

}