Null Safe To String
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 a content-based String representation if <code>obj</code> is
* not <code>null</code>; otherwise returns an empty String.
* <p>Differs from {@link #nullSafeToString(Object)} in that it returns
* an empty String rather than "null" for a <code>null</code> value.
* @param obj the object to build a display String for
* @return a display String representation of <code>obj</code>
* @see #nullSafeToString(Object)
*/
public static String getDisplayString(Object obj) {
if (obj == null) {
return EMPTY_STRING;
}
return nullSafeToString(obj);
}
/**
* Determine the class name for the given object.
* <p>Returns <code>"null"</code> if <code>obj</code> is <code>null</code>.
* @param obj the object to introspect (may be <code>null</code>)
* @return the corresponding class name
*/
public static String nullSafeClassName(Object obj) {
return (obj != null ? obj.getClass().getName() : NULL_STRING);
}
/**
* Return a String representation of the specified Object.
* <p>Builds a String representation of the contents in case of an array.
* Returns <code>"null"</code> if <code>obj</code> is <code>null</code>.
* @param obj the object to build a String representation for
* @return a String representation of <code>obj</code>
*/
public static String nullSafeToString(Object obj) {
if (obj == null) {
return NULL_STRING;
}
if (obj instanceof String) {
return (String) obj;
}
if (obj instanceof Object[]) {
return nullSafeToString((Object[]) obj);
}
if (obj instanceof boolean[]) {
return nullSafeToString((boolean[]) obj);
}
if (obj instanceof byte[]) {
return nullSafeToString((byte[]) obj);
}
if (obj instanceof char[]) {
return nullSafeToString((char[]) obj);
}
if (obj instanceof double[]) {
return nullSafeToString((double[]) obj);
}
if (obj instanceof float[]) {
return nullSafeToString((float[]) obj);
}
if (obj instanceof int[]) {
return nullSafeToString((int[]) obj);
}
if (obj instanceof long[]) {
return nullSafeToString((long[]) obj);
}
if (obj instanceof short[]) {
return nullSafeToString((short[]) obj);
}
String str = obj.toString();
return (str != null ? str : EMPTY_STRING);
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(Object[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(String.valueOf(array[i]));
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(boolean[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(byte[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(char[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append("'").append(array[i]).append("'");
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(double[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(float[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(int[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(long[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
/**
* Return a String representation of the contents of the specified array.
* <p>The String representation consists of a list of the array's elements,
* enclosed in curly braces (<code>"{}"</code>). Adjacent elements are separated
* by the characters <code>", "</code> (a comma followed by a space). Returns
* <code>"null"</code> if <code>array</code> is <code>null</code>.
* @param array the array to build a String representation for
* @return a String representation of <code>array</code>
*/
public static String nullSafeToString(short[] array) {
if (array == null) {
return NULL_STRING;
}
int length = array.length;
if (length == 0) {
return EMPTY_ARRAY;
}
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < length; i++) {
if (i == 0) {
buffer.append(ARRAY_START);
}
else {
buffer.append(ARRAY_ELEMENT_SEPARATOR);
}
buffer.append(array[i]);
}
buffer.append(ARRAY_END);
return buffer.toString();
}
}
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