ObjectUtils.java Source code

Introduction

Here is the source code for ObjectUtils.java

Source

import java.lang.reflect.Array;
import java.util.Arrays;

/*
 * Copyright 2002-2007 the original author or authors.
 *
 * 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.
 */

//Revised from springframework

/**
 * Miscellaneous object utility methods. Mainly for internal use within the
 * framework; consider Jakarta's Commons Lang for a more comprehensive suite
 * of object utilities.
 *
 * @author Juergen Hoeller
 * @author Keith Donald
 * @author Rod Johnson
 * @author Rob Harrop
 * @author Alex Ruiz
 * @since 19.03.2004
 * @see org.apache.commons.lang.ObjectUtils
 */
abstract class ObjectUtils {

    private static final int INITIAL_HASH = 7;
    private static final int MULTIPLIER = 31;

    private static final String EMPTY_STRING = "";
    private static final String NULL_STRING = "null";
    private static final String ARRAY_START = "{";
    private static final String ARRAY_END = "}";
    private static final String EMPTY_ARRAY = ARRAY_START + ARRAY_END;
    private static final String ARRAY_ELEMENT_SEPARATOR = ", ";

    /**
     * Return whether the given array is empty: that is, <code>null</code>
     * or of zero length.
     * @param array the array to check
     * @return whether the given array is empty
     */
    public static boolean isEmpty(Object[] array) {
        return (array == null || array.length == 0);
    }

    /**
     * Append the given Object to the given array, returning a new array
     * consisting of the input array contents plus the given Object.
     * @param array the array to append to (can be <code>null</code>)
     * @param obj the Object to append
     * @return the new array (of the same component type; never <code>null</code>)
     */
    public static Object[] addObjectToArray(Object[] array, Object obj) {
        Class compType = Object.class;
        if (array != null) {
            compType = array.getClass().getComponentType();
        } else if (obj != null) {
            compType = obj.getClass();
        }
        int newArrLength = (array != null ? array.length + 1 : 1);
        Object[] newArr = (Object[]) Array.newInstance(compType, newArrLength);
        if (array != null) {
            System.arraycopy(array, 0, newArr, 0, array.length);
        }
        newArr[newArr.length - 1] = obj;
        return newArr;
    }

    /**
     * Convert the given array (which may be a primitive array) to an
     * object array (if necessary of primitive wrapper objects).
     * <p>A <code>null</code> source value will be converted to an
     * empty Object array.
     * @param source the (potentially primitive) array
     * @return the corresponding object array (never <code>null</code>)
     * @throws IllegalArgumentException if the parameter is not an array
     */
    public static Object[] toObjectArray(Object source) {
        if (source instanceof Object[]) {
            return (Object[]) source;
        }
        if (source == null) {
            return new Object[0];
        }
        if (!source.getClass().isArray()) {
            throw new IllegalArgumentException("Source is not an array: " + source);
        }
        int length = Array.getLength(source);
        if (length == 0) {
            return new Object[0];
        }
        Class wrapperType = Array.get(source, 0).getClass();
        Object[] newArray = (Object[]) Array.newInstance(wrapperType, length);
        for (int i = 0; i < length; i++) {
            newArray[i] = Array.get(source, i);
        }
        return newArray;
    }

}