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/*
* Copyright 2002-2019 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
*
* https://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 com.feilong.lib.springframework.util;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Collection;
import java.util.Map;
/**
* Miscellaneous object utility methods.
*
*
* Mainly for internal use within the framework.
*
*
* Thanks to Alex Ruiz for contributing several enhancements to this class!
*
* @author Juergen Hoeller
* @author Keith Donald
* @author Rod Johnson
* @author Rob Harrop
* @author Chris Beams
* @author Sam Brannen
* @since 19.03.2004
* @see ClassUtils
* @see CollectionUtils
* @see StringUtils
*/
public 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 = ", ";
/**
* Determine whether the given array is empty:
* i.e. {@code null} or of zero length.
*
* @param array
* the array to check
* @see #isEmpty(Object)
*/
public static boolean isEmpty(Object[] array){
return (array == null || array.length == 0);
}
/**
* Determine whether the given object is empty.
*
* This method supports the following object types.
*
* - {@code Array}: considered empty if its length is zero
* - {@link CharSequence}: considered empty if its length is zero
* - {@link Collection}: delegates to {@link Collection#isEmpty()}
* - {@link Map}: delegates to {@link Map#isEmpty()}
*
*
* If the given object is non-null and not one of the aforementioned
* supported types, this method returns {@code false}.
*
* @param obj
* the object to check
* @return {@code true} if the object is {@code null} or empty
* @since 4.2
* @see ObjectUtils#isEmpty(Object[])
*/
@SuppressWarnings("rawtypes")
public static boolean isEmpty(Object obj){
if (obj == null){
return true;
}
if (obj instanceof CharSequence){
return ((CharSequence) obj).length() == 0;
}
if (obj.getClass().isArray()){
return Array.getLength(obj) == 0;
}
if (obj instanceof Collection){
return ((Collection) obj).isEmpty();
}
if (obj instanceof Map){
return ((Map) obj).isEmpty();
}
// else
return false;
}
/**
* Check whether the given array of enum constants contains a constant with the given name,
* ignoring case when determining a match.
*
* @param enumValues
* the enum values to check, typically obtained via {@code MyEnum.values()}
* @param constant
* the constant name to find (must not be null or empty string)
* @return whether the constant has been found in the given array
*/
public static boolean containsConstant(Enum[] enumValues,String constant){
return containsConstant(enumValues, constant, false);
}
/**
* Check whether the given array of enum constants contains a constant with the given name.
*
* @param enumValues
* the enum values to check, typically obtained via {@code MyEnum.values()}
* @param constant
* the constant name to find (must not be null or empty string)
* @param caseSensitive
* whether case is significant in determining a match
* @return whether the constant has been found in the given array
*/
public static boolean containsConstant(Enum[] enumValues,String constant,boolean caseSensitive){
for (Enum candidate : enumValues){
if (caseSensitive ? candidate.toString().equals(constant) : candidate.toString().equalsIgnoreCase(constant)){
return true;
}
}
return false;
}
//---------------------------------------------------------------------
// Convenience methods for content-based equality/hash-code handling
//---------------------------------------------------------------------
/**
* Determine if the given objects are equal, returning {@code true} if
* both are {@code null} or {@code false} if only one is {@code null}.
*
* Compares arrays with {@code Arrays.equals}, performing an equality
* check based on the array elements rather than the array reference.
*
* @param o1
* first Object to compare
* @param o2
* second Object to compare
* @return whether the given objects are equal
* @see Object#equals(Object)
* @see java.util.Arrays#equals
*/
public static boolean nullSafeEquals(Object o1,Object o2){
if (o1 == o2){
return true;
}
if (o1 == null || o2 == null){
return false;
}
if (o1.equals(o2)){
return true;
}
if (o1.getClass().isArray() && o2.getClass().isArray()){
return arrayEquals(o1, o2);
}
return false;
}
/**
* Compare the given arrays with {@code Arrays.equals}, performing an equality
* check based on the array elements rather than the array reference.
*
* @param o1
* first array to compare
* @param o2
* second array to compare
* @return whether the given objects are equal
* @see #nullSafeEquals(Object, Object)
* @see java.util.Arrays#equals
*/
private static boolean arrayEquals(Object o1,Object o2){
if (o1 instanceof Object[] && o2 instanceof Object[]){
return Arrays.equals((Object[]) o1, (Object[]) o2);
}
if (o1 instanceof boolean[] && o2 instanceof boolean[]){
return Arrays.equals((boolean[]) o1, (boolean[]) o2);
}
if (o1 instanceof byte[] && o2 instanceof byte[]){
return Arrays.equals((byte[]) o1, (byte[]) o2);
}
if (o1 instanceof char[] && o2 instanceof char[]){
return Arrays.equals((char[]) o1, (char[]) o2);
}
if (o1 instanceof double[] && o2 instanceof double[]){
return Arrays.equals((double[]) o1, (double[]) o2);
}
if (o1 instanceof float[] && o2 instanceof float[]){
return Arrays.equals((float[]) o1, (float[]) o2);
}
if (o1 instanceof int[] && o2 instanceof int[]){
return Arrays.equals((int[]) o1, (int[]) o2);
}
if (o1 instanceof long[] && o2 instanceof long[]){
return Arrays.equals((long[]) o1, (long[]) o2);
}
if (o1 instanceof short[] && o2 instanceof short[]){
return Arrays.equals((short[]) o1, (short[]) o2);
}
return false;
}
/**
* Return as hash code for the given object; typically the value of
* {@code Object#hashCode()}}. If the object is an array,
* this method will delegate to any of the {@code nullSafeHashCode}
* methods for arrays in this class. If the object is {@code null},
* this method returns 0.
*
* @see Object#hashCode()
* @see #nullSafeHashCode(Object[])
* @see #nullSafeHashCode(boolean[])
* @see #nullSafeHashCode(byte[])
* @see #nullSafeHashCode(char[])
* @see #nullSafeHashCode(double[])
* @see #nullSafeHashCode(float[])
* @see #nullSafeHashCode(int[])
* @see #nullSafeHashCode(long[])
* @see #nullSafeHashCode(short[])
*/
public static int nullSafeHashCode(Object obj){
if (obj == null){
return 0;
}
if (obj.getClass().isArray()){
if (obj instanceof Object[]){
return nullSafeHashCode((Object[]) obj);
}
if (obj instanceof boolean[]){
return nullSafeHashCode((boolean[]) obj);
}
if (obj instanceof byte[]){
return nullSafeHashCode((byte[]) obj);
}
if (obj instanceof char[]){
return nullSafeHashCode((char[]) obj);
}
if (obj instanceof double[]){
return nullSafeHashCode((double[]) obj);
}
if (obj instanceof float[]){
return nullSafeHashCode((float[]) obj);
}
if (obj instanceof int[]){
return nullSafeHashCode((int[]) obj);
}
if (obj instanceof long[]){
return nullSafeHashCode((long[]) obj);
}
if (obj instanceof short[]){
return nullSafeHashCode((short[]) obj);
}
}
return obj.hashCode();
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(Object[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (Object element : array){
hash = MULTIPLIER * hash + nullSafeHashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(boolean[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (boolean element : array){
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(byte[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (byte element : array){
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(char[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (char element : array){
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(double[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (double element : array){
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(float[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (float element : array){
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(int[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (int element : array){
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(long[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (long element : array){
hash = MULTIPLIER * hash + hashCode(element);
}
return hash;
}
/**
* Return a hash code based on the contents of the specified array.
* If {@code array} is {@code null}, this method returns 0.
*/
public static int nullSafeHashCode(short[] array){
if (array == null){
return 0;
}
int hash = INITIAL_HASH;
for (short element : array){
hash = MULTIPLIER * hash + element;
}
return hash;
}
/**
* Return the same value as {@link Boolean#hashCode()}}.
*
* @see Boolean#hashCode()
*/
public static int hashCode(boolean bool){
return (bool ? 1231 : 1237);
}
/**
* Return the same value as {@link Double#hashCode()}}.
*
* @param dbl
* @return
*
* @see Double#hashCode()
*/
public static int hashCode(double dbl){
return hashCode(Double.doubleToLongBits(dbl));
}
/**
* Return the same value as {@link Float#hashCode()}}.
*
* @see Float#hashCode()
*/
public static int hashCode(float flt){
return Float.floatToIntBits(flt);
}
/**
* Return the same value as {@link Long#hashCode()}}.
*
* @see Long#hashCode()
*/
public static int hashCode(long lng){
return (int) (lng ^ (lng >>> 32));
}
//---------------------------------------------------------------------
// Convenience methods for toString output
//---------------------------------------------------------------------
/**
* Return a String representation of an object's overall identity.
*
* @param obj
* the object (may be {@code null})
* @return the object's identity as String representation,
* or an empty String if the object was {@code null}
*/
public static String identityToString(Object obj){
if (obj == null){
return EMPTY_STRING;
}
return obj.getClass().getName() + "@" + getIdentityHexString(obj);
}
/**
* Return a hex String form of an object's identity hash code.
*
* @param obj
* the object
* @return the object's identity code in hex notation
*/
public static String getIdentityHexString(Object obj){
return Integer.toHexString(System.identityHashCode(obj));
}
/**
* Return a content-based String representation if {@code obj} is
* not {@code null}; otherwise returns an empty String.
*
* Differs from {@link #nullSafeToString(Object)} in that it returns
* an empty String rather than "null" for a {@code null} value.
*
* @param obj
* the object to build a display String for
* @return a display String representation of {@code obj}
* @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.
*
* Returns a {@code "null"} String if {@code obj} is {@code null}.
*
* @param obj
* the object to introspect (may be {@code null})
* @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.
*
* Builds a String representation of the contents in case of an array.
* Returns a {@code "null"} String if {@code obj} is {@code null}.
*
* @param obj
* the object to build a String representation for
* @return a String representation of {@code obj}
*/
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.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(Object[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(String.valueOf(array[i]));
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(boolean[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(byte[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(char[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append("'").append(array[i]).append("'");
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(double[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(float[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(int[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(long[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
/**
* Return a String representation of the contents of the specified array.
*
* The String representation consists of a list of the array's elements,
* enclosed in curly braces ({@code "{}"}). Adjacent elements are separated
* by the characters {@code ", "} (a comma followed by a space).
* Returns a {@code "null"} String if {@code array} is {@code null}.
*
* @param array
* the array to build a String representation for
* @return a String representation of {@code array}
*/
public static String nullSafeToString(short[] array){
if (array == null){
return NULL_STRING;
}
int length = array.length;
if (length == 0){
return EMPTY_ARRAY;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < length; i++){
if (i == 0){
sb.append(ARRAY_START);
}else{
sb.append(ARRAY_ELEMENT_SEPARATOR);
}
sb.append(array[i]);
}
sb.append(ARRAY_END);
return sb.toString();
}
}