ObjectUtils (Spring Framework API 2.1) - Spring Framework 2.1.0 API 文档英文版

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org.springframework.util
Class ObjectUtils

java.lang.Object
  org.springframework.util.ObjectUtils

public abstract class ObjectUtils
extends Object
extends Object

Miscellaneous object utility methods. Mainly for internal use within the framework; consider Jakarta's Commons Lang for a more comprehensive suite of object utilities.

Since:: 19.03.2004
Author:: Juergen Hoeller, Keith Donald, Rod Johnson, Rob Harrop, Alex Ruiz
See Also:: org.apache.commons.lang.ObjectUtils

Constructor Summary

ObjectUtils()


Method Summary

static Object[] addObjectToArray(Object[] array, Object obj)
          Append the given Object to the given array, returning a new array consisting of the input array contents plus the given Object.

static String getDisplayString(Object obj)
          Return a content-based String representation if obj is not null; otherwise returns an empty String.

static String getIdentityHexString(Object obj)
          Return a hex String form of an object's identity hash code.

static int hashCode(boolean bool)
          Return the same value as Boolean.hashCode().

static int hashCode(double dbl)
          Return the same value as Double.hashCode().

static int hashCode(float flt)
          Return the same value as Float.hashCode().

static int hashCode(long lng)
          Return the same value as Long.hashCode().

static String identityToString(Object obj)
          Return a String representation of an object's overall identity.

static boolean isCheckedException(Throwable ex)
          Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.

static boolean isCompatibleWithThrowsClause(Throwable ex, Class[] declaredExceptions)
          Check whether the given exception is compatible with the exceptions declared in a throws clause.

static boolean isEmpty(Object[] array)
          Return whether the given array is empty: that is, null or of zero length.

static String nullSafeClassName(Object obj)
          Determine the class name for the given object.

static boolean nullSafeEquals(Object o1, Object o2)
          Determine if the given objects are equal, returning true if both are null or false if only one is null.

static int nullSafeHashCode(boolean[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(byte[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(char[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(double[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(float[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(int[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(long[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(Object obj)
          Return as hash code for the given object; typically the value of Object.hashCode().

static int nullSafeHashCode(Object[] array)
          Return a hash code based on the contents of the specified array.

static int nullSafeHashCode(short[] array)
          Return a hash code based on the contents of the specified array.

static String nullSafeToString(boolean[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(byte[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(char[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(double[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(float[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(int[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(long[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(Object obj)
          Return a String representation of the specified Object.

static String nullSafeToString(Object[] array)
          Return a String representation of the contents of the specified array.

static String nullSafeToString(short[] array)
          Return a String representation of the contents of the specified array.

static Object[] toObjectArray(Object source)
          Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Summary
`ObjectUtils()`

Method Summary
`static Object[]`	`addObjectToArray(Object[] array, Object obj)` Append the given Object to the given array, returning a new array consisting of the input array contents plus the given Object.
`static String`	`getDisplayString(Object obj)` Return a content-based String representation if `obj` is not `null`; otherwise returns an empty String.
`static String`	`getIdentityHexString(Object obj)` Return a hex String form of an object's identity hash code.
`static int`	`hashCode(boolean bool)` Return the same value as `Boolean.hashCode()`.
`static int`	`hashCode(double dbl)` Return the same value as `Double.hashCode()`.
`static int`	`hashCode(float flt)` Return the same value as `Float.hashCode()`.
`static int`	`hashCode(long lng)` Return the same value as `Long.hashCode()`.
`static String`	`identityToString(Object obj)` Return a String representation of an object's overall identity.
`static boolean`	`isCheckedException(Throwable ex)` Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.
`static boolean`	`isCompatibleWithThrowsClause(Throwable ex, Class[] declaredExceptions)` Check whether the given exception is compatible with the exceptions declared in a throws clause.
`static boolean`	`isEmpty(Object[] array)` Return whether the given array is empty: that is, `null` or of zero length.
`static String`	`nullSafeClassName(Object obj)` Determine the class name for the given object.
`static boolean`	`nullSafeEquals(Object o1, Object o2)` Determine if the given objects are equal, returning `true` if both are `null` or `false` if only one is `null`.
`static int`	`nullSafeHashCode(boolean[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(byte[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(char[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(double[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(float[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(int[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(long[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(Object obj)` Return as hash code for the given object; typically the value of `Object.hashCode()`.
`static int`	`nullSafeHashCode(Object[] array)` Return a hash code based on the contents of the specified array.
`static int`	`nullSafeHashCode(short[] array)` Return a hash code based on the contents of the specified array.
`static String`	`nullSafeToString(boolean[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(byte[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(char[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(double[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(float[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(int[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(long[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(Object obj)` Return a String representation of the specified Object.
`static String`	`nullSafeToString(Object[] array)` Return a String representation of the contents of the specified array.
`static String`	`nullSafeToString(short[] array)` Return a String representation of the contents of the specified array.
`static Object[]`	`toObjectArray(Object source)` Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

ObjectUtils

public ObjectUtils()

Method Detail

isCheckedException

public static boolean isCheckedException(Throwable ex)

Return whether the given throwable is a checked exception: that is, neither a RuntimeException nor an Error.

Parameters:: ex - the throwable to check
Returns:: whether the throwable is a checked exception
See Also:: Exception, RuntimeException, Error

isCompatibleWithThrowsClause

public static boolean isCompatibleWithThrowsClause(Throwable ex,
                                                   Class[] declaredExceptions)

Check whether the given exception is compatible with the exceptions declared in a throws clause.

Parameters:: ex - the exception to checked; declaredExceptions - the exceptions declared in the throws clause
Returns:: whether the given exception is compatible

isEmpty

public static boolean isEmpty(Object[] array)

Return whether the given array is empty: that is, null or of zero length.

Parameters:: array - the array to check
Returns:: whether the given array is empty

addObjectToArray

public static Object[] addObjectToArray(Object[] array,
                                        Object obj)

Append the given Object to the given array, returning a new array consisting of the input array contents plus the given Object.

Parameters:: array - the array to append to (can be null); obj - the Object to append
Returns:: the new array (of the same component type; never null)

toObjectArray

public static Object[] toObjectArray(Object source)

Convert the given array (which may be a primitive array) to an object array (if necessary of primitive wrapper objects).

A null source value will be converted to an empty Object array.

Parameters:: source - the (potentially primitive) array
Returns:: the corresponding object array (never null)
Throws:: IllegalArgumentException - if the parameter is not an array

nullSafeEquals

public static boolean nullSafeEquals(Object o1,
                                     Object o2)

Determine if the given objects are equal, returning true if both are null or false if only one is null.

Compares arrays with Arrays.equals, performing an equality check based on the array elements rather than the array reference.

Parameters:: o1 - first Object to compare; o2 - second Object to compare
Returns:: whether the given objects are equal
See Also:: Arrays.equals(long[], long[])

nullSafeHashCode

public static int nullSafeHashCode(Object obj)

Return as hash code for the given object; typically the value of Object.hashCode(). If the object is an array, this method will delegate to any of the nullSafeHashCode methods for arrays in this class. If the object is null, this method returns 0.

See Also:: nullSafeHashCode(Object[]), nullSafeHashCode(boolean[]), nullSafeHashCode(byte[]), nullSafeHashCode(char[]), nullSafeHashCode(double[]), nullSafeHashCode(float[]), nullSafeHashCode(int[]), nullSafeHashCode(long[]), nullSafeHashCode(short[])