sk.baka.tools
Class JavaUtils

java.lang.Object
  sk.baka.tools.JavaUtils

public final class JavaUtils
extends Object

Contains several utilities for classic java classes.

Author:

Martin Vysny

Nested Class Summary

static class	JavaUtils.BeanProperty Contains accessors to a bean property.
static interface	JavaUtils.IEqualsComparator Compares two objects.

Field Summary

static JavaUtils.IEqualsComparator

COMPARATOR_EQUALS Compares two objects using equals(java.lang.Object, java.lang.Object).

Method Summary

static Date	clone(Date date) Clones given date object.
static boolean	equals(Object o1, Object o2) Checks that two objects are equal.
static <T> JavaUtils.BeanProperty	equalsBean(T bean1, T bean2) Compares two beans.
static <T> JavaUtils.BeanProperty	equalsBean(T bean1, T bean2, JavaUtils.IEqualsComparator comparator) Compares two beans.
static List<JavaUtils.BeanProperty>	getBeanProperties(Class<?> beanClass, boolean includeSuperclasses) Returns all property accessors from given class, and optionally from its superclasses.
static Method	getGetter(Field field) Returns a getter method for given field, if such a method exists in the same class.
static InputStream	getResource(String resource) Tries to obtain an input stream for given resource.
static Method	getSetter(Field field) Returns a setter method for given field, if such a method exists in the same class.
static String	getStacktrace(Throwable t) Returns a stacktrace of given throwable
static boolean	isBlank(Object array) Deprecated. use isBlankArray(java.lang.Object)
static boolean	isBlankArray(Object array) Returns true if given array is null, zero-sized or contains only nulls.
static boolean	isEmpty(Object array) Deprecated. use #isEmptyList(java.lang.Object)
static boolean	isEmptyArray(Object array) Returns true if given array is null or zero-sized.
static boolean	isEnum(Class<?> clazz) A workaround around broken Class.isEnum() which returns false for more complex enums (enums which define abstract methods and let each constant override the method).
static boolean	isPrimitiveArray(Object array) Checks whether given array is an array of primitives.
static Properties	loadProperties(InputStream in) Loads properties from given input stream.
static Properties	loadProperties(String filename) Loads properties from given file.
static List<Object>	toList(Object array) Creates a new list and copies given array to it.

Methods inherited from class java.lang.Object

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

Field Detail

COMPARATOR_EQUALS

public static final JavaUtils.IEqualsComparator COMPARATOR_EQUALS

Compares two objects using equals(java.lang.Object, java.lang.Object).

Method Detail

clone

public static Date clone(Date date)

Clones given date object.

Parameters:

date - the date to clone, may be null

Returns:

cloned date object or null

loadProperties

public static Properties loadProperties(String filename)
                                 throws IOException

Loads properties from given file.

Parameters:

filename - the file to load the properties from.

Returns:

the properties instance, never null

Throws:

IOException - if i/o error occurs or the file does not exist.

loadProperties

public static Properties loadProperties(InputStream in)
                                 throws IOException

Loads properties from given input stream. The stream is always closed.

Parameters:

in - the input stream, always closed

Returns:

properties instance, never null

Throws:

IOException - on i/o error

getResource

public static InputStream getResource(String resource)
                               throws IOException

Tries to obtain an input stream for given resource. Fails if the resource does not exist. Always uses context class loader.

Parameters:

resource - the resource to read

Returns:

input stream, never null

Throws:

IOException - if the resource is not found

isEmpty

@Deprecated
public static boolean isEmpty(Object array)

Deprecated. use #isEmptyList(java.lang.Object)

Returns true if given array is null or zero-sized. Accepts:

• Collections
• both arrays of primitives and Objects
• Enumerations
• Iterators and Iterables

Parameters:

array - the array to check. null array is empty by definition.

Returns:

true if null or zero-sized, false otherwise.

isEmptyArray

public static boolean isEmptyArray(Object array)

Returns true if given array is null or zero-sized. Accepts:

• Collections
• both arrays of primitives and Objects
• Enumerations
• Iterators and Iterables

Parameters:

array - the array to check. null array is empty by definition.

Returns:

true if null or zero-sized, false otherwise.

isBlank

@Deprecated
public static boolean isBlank(Object array)

Deprecated. use isBlankArray(java.lang.Object)

Returns true if given array is null, zero-sized or contains only nulls. Accepts:

• Collections
• both arrays of primitives and Objects
• Enumerations
• Iterators and Iterables

Warning: the operation is destructive on Enumerations and Iterators as items are actually read from them.

Parameters:

array - the array to check, may be both primitive, Object array and a Collection.

Returns:

true if null or zero-sized, false otherwise.

isBlankArray

public static boolean isBlankArray(Object array)

Returns true if given array is null, zero-sized or contains only nulls. Accepts:

• Collections
• both arrays of primitives and Objects
• Enumerations
• Iterators and Iterables

Warning: the operation is destructive on Enumerations and Iterators as items are actually read from them.

Parameters:

array - the array to check, may be both primitive, Object array and a Collection.

Returns:

true if null or zero-sized, false otherwise.

isPrimitiveArray

public static boolean isPrimitiveArray(Object array)

Checks whether given array is an array of primitives.

Parameters:

array - an array.

Returns:

true if the array is an array of primitives, false if it is a Object[], String[] etc.

getStacktrace

public static String getStacktrace(Throwable t)

Returns a stacktrace of given throwable

Parameters:

t - the throwable to return

Returns:

stacktrace, never null.

equals

public static boolean equals(Object o1,
                             Object o2)

Checks that two objects are equal. Handles nulls.

Parameters:

o1 - first object, may be null

o2 - first object, may be null

Returns:

true if both objects are null or they are equal, false otherwise.

toList

public static List<Object> toList(Object array)

Creates a new list and copies given array to it. Accepts:

• Collections
• both arrays of primitives and Objects
• Enumerations
• Iterators and Iterables

Parameters:

array - the array to convert, may be null.

Returns:

a list of objects. An empty list if null was provided.

getGetter

public static Method getGetter(Field field)

Returns a getter method for given field, if such a method exists in the same class.

Parameters:

field - a field reference.

Returns:

getter method or null if no such method exists.

getSetter

public static Method getSetter(Field field)

Returns a setter method for given field, if such a method exists in the same class.

Parameters:

field - a field reference.

Returns:

setter method or null if no such method exists.

getBeanProperties

public static List<JavaUtils.BeanProperty> getBeanProperties(Class<?> beanClass,
                                                             boolean includeSuperclasses)

Returns all property accessors from given class, and optionally from its superclasses.

Parameters:

beanClass - the bean class

includeSuperclasses - if true then class superclasses are considered as well.

Returns:

list of fields and their getters

equalsBean

public static <T> JavaUtils.BeanProperty equalsBean(T bean1,
                                                    T bean2)

Compares two beans. Fails if some of their properties are not equal. Uses regular Object.equals(java.lang.Object) on field values (does not perform recursive comparison).

Type Parameters:

T - the bean type

Parameters:

bean1 - first bean, must not be null

bean2 - second bean, must not be null

Returns:

null if beans equals, a mismatched property reference otherwise.

Throws:

IllegalArgumentException - if beans do not have same class.

NullPointerException - if at least one of the parameter is null

equalsBean

public static <T> JavaUtils.BeanProperty equalsBean(T bean1,
                                                    T bean2,
                                                    JavaUtils.IEqualsComparator comparator)

Compares two beans. Fails if some of their properties are not equal. Uses given comparator to compare field values.

Type Parameters:

T - the bean type

Parameters:

bean1 - first bean, must not be null

bean2 - second bean, must not be null

comparator - use this comparator when comparing bean property values.

Returns:

null if beans equals, a mismatched property reference otherwise.

Throws:

IllegalArgumentException - if beans do not have same class.

NullPointerException - if at least one of the parameter is null

isEnum

public static boolean isEnum(Class<?> clazz)

A workaround around broken Class.isEnum() which returns false for more complex enums (enums which define abstract methods and let each constant override the method).

Parameters:

clazz -

Returns: