org.directwebremoting.util
Class LocalUtil

java.lang.Object
  org.directwebremoting.util.LocalUtil

public final class LocalUtil
extends java.lang.Object

Various utilities, stuff that we're still surprised isn't in the JDK, and stuff that perhaps is borderline JDK material, but isn't really pure DWR either.

Author:

Joe Walker [joe at getahead dot ltd dot uk]

Field Summary

static int	INBOUND_INDEX_TYPE splitInbound() returns the type info in this parameter
static int	INBOUND_INDEX_VALUE splitInbound() returns the value info in this parameter

Method Summary

static void	addNoCacheHeaders(javax.servlet.http.HttpServletResponse resp) Add headers to prevent browsers and proxies from caching this reply.
static java.lang.Class<?>	classForName(java.lang.String className) Utility to essentially do Class forName and allow configurable Classloaders.
static <T> java.lang.Class<? extends T>	classForName(java.lang.String debugContext, java.lang.String className, java.lang.Class<T> impl) Utility to essentially do Class forName with the assumption that the environment expects failures for missing jar files and can carry on if this process fails.
static <T> T	classNewInstance(java.lang.String name, java.lang.String className, java.lang.Class<T> impl) Utility to essentially do Class forName and newInstance with the assumption that the environment expects failures for missing jar files and can carry on if this process fails.
static void	close(java.io.Closeable in) InputStream closer that can cope if the input stream is null.
static java.lang.String	decode(java.lang.String value) URL decode a value.
static java.lang.reflect.Field[]	getAllFields(java.lang.Class<?> clazz) Return a list of all fields (whatever access status, and on whatever superclass they were defined) that can be found on this class.
static java.util.List<java.lang.Class<?>>	getAllSuperclasses(java.lang.Class<?> clazz) Return a List of super-classes for the given class.
static java.lang.Class<?>	getNonPrimitiveType(java.lang.Class<?> type)
static java.lang.Object	invoke(java.lang.Object object, java.lang.reflect.Method method, java.lang.Object[] params) Calling methods using reflection is useful for graceful fallback - this is a helper method to make this easy
static boolean	isEquivalent(java.lang.Class<?> c1, java.lang.Class<?> c2) True if c1 is java.lang.Boolean and c2 is boolean, etc.
static boolean	isJavaIdentifier(java.lang.String test) Determines if the specified string is permissible as a Java identifier.
static boolean	isLetterOrDigitOrUnderline(java.lang.String test) Determines if the specified string contains only Unicode letters or digits as defined by Character.isLetterOrDigit(char)
static boolean	isServletClass(java.lang.Class<?> paramType) Is this class one that we auto fill, so the user can ignore?
static boolean	isSimpleName(java.lang.String name) Is this object property one that we can use in a JSON style or do we need to get fancy.
static boolean	isTypeSimplyConvertable(java.lang.Class<?> paramType) Can the type be used in a call to simpleConvert(String, Class)?
static java.lang.String	join(java.lang.Object[] array, java.lang.String separator) Create a string by joining the array elements together with the separator in-between each element.
static void	setParams(java.lang.Object object, java.util.Map<java.lang.String,?> params, java.util.List<java.lang.String> ignore) Set use reflection to set the setters on the object called by the keys in the params map with the corresponding values
static void	setProperty(java.lang.Object object, java.lang.String key, java.lang.Object value) Set a property on an object using reflection
static <T> T	simpleConvert(java.lang.String value, java.lang.Class<T> paramType) A very simple conversion function for all the IoC style setup and reflection that we are doing.

Methods inherited from class java.lang.Object

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

Field Detail

INBOUND_INDEX_TYPE

public static final int INBOUND_INDEX_TYPE

splitInbound() returns the type info in this parameter

See Also:

Constant Field Values

INBOUND_INDEX_VALUE

public static final int INBOUND_INDEX_VALUE

splitInbound() returns the value info in this parameter

See Also:

Constant Field Values

Method Detail

join

public static java.lang.String join(java.lang.Object[] array,
                                    java.lang.String separator)

Create a string by joining the array elements together with the separator in-between each element. A null (in the array or as a separator) is treated as an empty string.

Parameters:

array - The array of elements to join

separator - The string sequence to place between array elements

Returns:

A string containing the joined elements

isJavaIdentifier

public static boolean isJavaIdentifier(java.lang.String test)

Determines if the specified string is permissible as a Java identifier. Returns true if the string is non-null, non-zero length with a Java identifier start as the first character and Java identifier parts in all remaining characters.

Parameters:

test - the string to be tested.

Returns:

true if the string is a Java identifier, false otherwise.

See Also:

Character.isJavaIdentifierPart(char), Character.isJavaIdentifierStart(char)

isLetterOrDigitOrUnderline

public static boolean isLetterOrDigitOrUnderline(java.lang.String test)

Determines if the specified string contains only Unicode letters or digits as defined by Character.isLetterOrDigit(char)

Parameters:

test - The string to test

Returns:

true if the string is non-null, non-empty and contains only characters that are unicode letters or digits

See Also:

Character.isLetterOrDigit(char)

isEquivalent

public static boolean isEquivalent(java.lang.Class<?> c1,
                                   java.lang.Class<?> c2)

True if c1 is java.lang.Boolean and c2 is boolean, etc.

Parameters:

c1 - the first class to test

c2 - the second class to test

Returns:

true if the classes are equivalent

getNonPrimitiveType

public static java.lang.Class<?> getNonPrimitiveType(java.lang.Class<?> type)

Parameters:

type - The class to de-primitivize

Returns:

The non-primitive version of the class

addNoCacheHeaders

public static void addNoCacheHeaders(javax.servlet.http.HttpServletResponse resp)

Add headers to prevent browsers and proxies from caching this reply.

Parameters:

resp - The response to add headers to

isServletClass

public static boolean isServletClass(java.lang.Class<?> paramType)

Is this class one that we auto fill, so the user can ignore?

Parameters:

paramType - The type to test

Returns:

true if the type is a Servlet type

decode

public static java.lang.String decode(java.lang.String value)

URL decode a value. URLDecoder.decode(String, String) throws an UnsupportedEncodingException, which is silly given that the most common use case will be to pass in "UTF-8"

Parameters:

value - The string to decode

Returns:

The decoded string

setParams

public static void setParams(java.lang.Object object,
                             java.util.Map<java.lang.String,?> params,
                             java.util.List<java.lang.String> ignore)

Set use reflection to set the setters on the object called by the keys in the params map with the corresponding values

Parameters:

object - The object to setup

params - The settings to use

ignore - List of keys to not warn about if they are not properties Note only the warning is skipped, we still try the setter

setProperty

public static void setProperty(java.lang.Object object,
                               java.lang.String key,
                               java.lang.Object value)
                        throws java.lang.NoSuchMethodException,
                               java.lang.SecurityException,
                               java.lang.IllegalAccessException,
                               java.lang.IllegalArgumentException,
                               java.lang.reflect.InvocationTargetException

Set a property on an object using reflection

Parameters:

object - The object to call the setter on

key - The name of the property to set.

value - The new value to use for the property

Throws:

java.lang.NoSuchMethodException - Passed on from reflection code

java.lang.SecurityException - Passed on from reflection code

java.lang.IllegalAccessException - Passed on from reflection code

java.lang.IllegalArgumentException - Passed on from reflection code

java.lang.reflect.InvocationTargetException - Passed on from reflection code

isTypeSimplyConvertable

public static boolean isTypeSimplyConvertable(java.lang.Class<?> paramType)

Can the type be used in a call to simpleConvert(String, Class)?

Parameters:

paramType - The type to test

Returns:

true if the type is acceptable to simpleConvert()

simpleConvert

public static <T> T simpleConvert(java.lang.String value,
                                  java.lang.Class<T> paramType)

A very simple conversion function for all the IoC style setup and reflection that we are doing.

Parameters:

value - The value to convert

paramType - The type to convert to. Currently any primitive types and String are supported.

Returns:

The converted object.

isSimpleName

public static boolean isSimpleName(java.lang.String name)

Is this object property one that we can use in a JSON style or do we need to get fancy. i.e does it contain only letters and numbers with an initial letter.

Parameters:

name - The name to test for JSON compatibility

Returns:

true if the name is simple

classForName

public static java.lang.Class<?> classForName(java.lang.String className)
                                       throws java.lang.ClassNotFoundException

Utility to essentially do Class forName and allow configurable Classloaders.

The initial implementation makes use of the context classloader for the current thread.

Parameters:

className - The class to create

Returns:

The class if it is safe or null otherwise.

Throws:

java.lang.ClassNotFoundException - If className is not valid

invoke

public static java.lang.Object invoke(java.lang.Object object,
                                      java.lang.reflect.Method method,
                                      java.lang.Object[] params)
                               throws java.lang.IllegalStateException

Calling methods using reflection is useful for graceful fallback - this is a helper method to make this easy

Parameters:

object - The object to use as 'this'

method - The method to call, can be null in which case null is returned

params - The parameters to pass to the reflection call

Returns:

The results of calling method.invoke() or null

Throws:

java.lang.IllegalStateException - If anything goes wrong

classForName

public static <T> java.lang.Class<? extends T> classForName(java.lang.String debugContext,
                                                            java.lang.String className,
                                                            java.lang.Class<T> impl)

Utility to essentially do Class forName with the assumption that the environment expects failures for missing jar files and can carry on if this process fails.

Type Parameters:

T - The base type that we want a class to implement

Parameters:

debugContext - The name for debugging purposes

className - The class to create

impl - The implementation class - what should className do?

Returns:

The class if it is safe or null otherwise.

classNewInstance

public static <T> T classNewInstance(java.lang.String name,
                                     java.lang.String className,
                                     java.lang.Class<T> impl)

Utility to essentially do Class forName and newInstance with the assumption that the environment expects failures for missing jar files and can carry on if this process fails.

Type Parameters:

T - The base type that we want a class to implement

Parameters:

name - The name for debugging purposes

className - The class to create

impl - The implementation class - what should className do?

Returns:

The new instance if it is safe or null otherwise.

close

public static void close(java.io.Closeable in)

InputStream closer that can cope if the input stream is null. If anything goes wrong, the errors are logged and ignored.

Parameters:

in - The resource to close

getAllSuperclasses

public static java.util.List<java.lang.Class<?>> getAllSuperclasses(java.lang.Class<?> clazz)

Return a List of super-classes for the given class.

Parameters:

clazz - the class to look up

Returns:

the List of super-classes in order going up from this one

getAllFields

public static java.lang.reflect.Field[] getAllFields(java.lang.Class<?> clazz)

Return a list of all fields (whatever access status, and on whatever superclass they were defined) that can be found on this class.

This is like a union of Class.getDeclaredFields() which ignores and super-classes, and Class.getFields() which ignored non-public fields

Parameters:

clazz - The class to introspect

Returns:

The complete list of fields