Class GosuObjectUtil
This class is directly derived from org.apache.commons.lang.ObjectUtils and is intended to avoid dependencies on that project.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionstatic classClass used as a null placeholder wherenullhas another meaning. -
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final GosuObjectUtil.NullSingleton used as anullplaceholder wherenullhas another meaning. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic StringBufferappendIdentityToString(StringBuffer buffer, Object object) Deprecated.The design of this method is bad - see LANG-360.static intarrayHashCode(Object array) Return the hash code for an arraystatic ObjectdefaultIfNull(Object object, Object defaultValue) Returns a default value if the object passed isnull.static booleanCompares two objects for equality, where either one or both objects may benull.static intGets the hash code of an object returning zero when the object isnull.static StringidentityToString(Object object) Gets the toString that would be produced byObjectif a class did not override toString itself.static voididentityToString(StringBuffer buffer, Object object) Appends the toString that would be produced byObjectif a class did not override toString itself.static booleanstatic Objectmax(Comparable c1, Comparable c2) Null safe comparison of Comparables.static Objectmin(Comparable c1, Comparable c2) Null safe comparison of Comparables.static StringGets thetoStringof anObjectreturning an empty string ("") ifnullinput.static StringGets thetoStringof anObjectreturning a specified text ifnullinput.
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Field Details
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NULL
Singleton used as a
nullplaceholder wherenullhas another meaning.For example, in a
HashMaptheHashMap.get(java.lang.Object)method returnsnullif theMapcontainsnullor if there is no matching key. TheNullplaceholder can be used to distinguish between these two cases.Another example is
Hashtable, wherenullcannot be stored.This instance is Serializable.
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Constructor Details
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GosuObjectUtil
public GosuObjectUtil()
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Method Details
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defaultIfNull
Returns a default value if the object passed is
null.ObjectUtils.defaultIfNull(null, null) = null ObjectUtils.defaultIfNull(null, "") = "" ObjectUtils.defaultIfNull(null, "zz") = "zz" ObjectUtils.defaultIfNull("abc", *) = "abc" ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE- Parameters:
object- theObjectto test, may benulldefaultValue- the default value to return, may benull- Returns:
objectif it is notnull, defaultValue otherwise
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equals
Compares two objects for equality, where either one or both objects may be
null.ObjectUtils.equals(null, null) = true ObjectUtils.equals(null, "") = false ObjectUtils.equals("", null) = false ObjectUtils.equals("", "") = true ObjectUtils.equals(Boolean.TRUE, null) = false ObjectUtils.equals(Boolean.TRUE, "true") = false ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE) = true ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false- Parameters:
object1- the first object, may benullobject2- the second object, may benull- Returns:
trueif the values of both objects are the same
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hashCode
Gets the hash code of an object returning zero when the object is
null.ObjectUtils.hashCode(null) = 0 ObjectUtils.hashCode(obj) = obj.hashCode()
- Parameters:
obj- the object to obtain the hash code of, may benull- Returns:
- the hash code of the object, or zero if null
- Since:
- 2.1
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identityToString
Gets the toString that would be produced by
Objectif a class did not override toString itself.nullwill returnnull.ObjectUtils.identityToString(null) = null ObjectUtils.identityToString("") = "java.lang.String@1e23" ObjectUtils.identityToString(Boolean.TRUE) = "java.lang.Boolean@7fa"- Parameters:
object- the object to create a toString for, may benull- Returns:
- the default toString text, or
nullifnullpassed in
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isJavaReferenceArray
- Returns:
- true if the given object is a pure java object array, false otherwise
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identityToString
Appends the toString that would be produced by
Objectif a class did not override toString itself.nullwill throw a NullPointerException for either of the two parameters.ObjectUtils.identityToString(buf, "") = buf.append("java.lang.String@1e23" ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa" ObjectUtils.identityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")- Parameters:
buffer- the buffer to append toobject- the object to create a toString for- Since:
- 2.4
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appendIdentityToString
Deprecated.The design of this method is bad - see LANG-360. Instead, use identityToString(StringBuffer, Object).Appends the toString that would be produced by
Objectif a class did not override toString itself.nullwill returnnull.ObjectUtils.appendIdentityToString(*, null) = null ObjectUtils.appendIdentityToString(null, "") = "java.lang.String@1e23" ObjectUtils.appendIdentityToString(null, Boolean.TRUE) = "java.lang.Boolean@7fa" ObjectUtils.appendIdentityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")- Parameters:
buffer- the buffer to append to, may benullobject- the object to create a toString for, may benull- Returns:
- the default toString text, or
nullifnullpassed in - Since:
- 2.0
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toString
Gets the
toStringof anObjectreturning an empty string ("") ifnullinput.ObjectUtils.toString(null) = "" ObjectUtils.toString("") = "" ObjectUtils.toString("bat") = "bat" ObjectUtils.toString(Boolean.TRUE) = "true"- Parameters:
obj- the Object totoString, may be null- Returns:
- the passed in Object's toString, or nullStr if
nullinput - Since:
- 2.0
- See Also:
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toString
Gets the
toStringof anObjectreturning a specified text ifnullinput.ObjectUtils.toString(null, null) = null ObjectUtils.toString(null, "null") = "null" ObjectUtils.toString("", "null") = "" ObjectUtils.toString("bat", "null") = "bat" ObjectUtils.toString(Boolean.TRUE, "null") = "true"- Parameters:
obj- the Object totoString, may be nullnullStr- the String to return ifnullinput, may be null- Returns:
- the passed in Object's toString, or nullStr if
nullinput - Since:
- 2.0
- See Also:
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min
Null safe comparison of Comparables.- Parameters:
c1- the first comparable, may be nullc2- the second comparable, may be null- Returns:
- If both objects are non-null and unequal, the lesser object.
- If both objects are non-null and equal, c1.
- If one of the comparables is null, the non-null object.
- If both the comparables are null, null is returned.
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max
Null safe comparison of Comparables.- Parameters:
c1- the first comparable, may be nullc2- the second comparable, may be null- Returns:
- If both objects are non-null and unequal, the greater object.
- If both objects are non-null and equal, c1.
- If one of the comparables is null, the non-null object.
- If both the comparables are null, null is returned.
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arrayHashCode
Return the hash code for an array- Parameters:
array- the array to compute the hash code.
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