net.greghaines.jesque.utils

Class JesqueUtils

java.lang.Object

net.greghaines.jesque.utils.JesqueUtils

public final class JesqueUtils
extends Object

Miscellaneous utilities.

Author:

Greg Haines

Method Summary

Modifier and Type	Method and Description
static List<String>	createBacktrace(Throwable t) Creates a Resque backtrace from a Throwable's stack trace.
static String	createKey(String namespace, Iterable<String> parts) Builds a namespaced Redis key with the given arguments.
static String	createKey(String namespace, String... parts) Builds a namespaced Redis key with the given arguments.
static <K,V> Map.Entry<K,V>	entry(K key, V value) Creates a Map.Entry out of the given key and value.
static boolean	equal(Throwable ex1, Throwable ex2) This is needed because Throwable doesn't override equals() and object equality is not what we want to test.
protected static Throwable	instantiateThrowable(String type, String message, Throwable cause, StackTraceElement[] stes)
static String	join(String sep, Iterable<String> strs) Join the given strings, separated by the given separator.
static String	join(String sep, String... strs) Join the given strings, separated by the given separator.
static <K,V> Map<K,V>	map(Map.Entry<? extends K,? extends V>... entries) A convenient way of creating a map on the fly.
static Object	materializeJob(Job job) Materializes a job by assuming the Job.getClassName() is a fully-qualified Java type.
static Object	materializeJob(Job job, Map<String,Class<?>> jobTypes) Materializes a job by looking up Job.getClassName() in the provided map of job types.
static boolean	nullSafeEquals(Object obj1, Object obj2) Test for equality.
protected static StackTraceElement[]	recreateStackTrace(List<String> bTrace)
static Throwable	recreateThrowable(String type, String message, List<String> backtrace) Recreate an exception from a type name, a message and a backtrace (created from JesqueUtils.createBacktrace(Throwable)).
static <K> Set<K>	set(K... keys) Creates a Set out of the given keys

Methods inherited from class java.lang.Object

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

Method Detail

join

public static String join(String sep,
                          String... strs)

Join the given strings, separated by the given separator.

Parameters:

sep - the separator

strs - the strings to join

Returns:

the joined string

join

public static String join(String sep,
                          Iterable<String> strs)

Join the given strings, separated by the given separator.

Parameters:

sep - the separator

strs - the strings to join

Returns:

the joined string

createKey

public static String createKey(String namespace,
                               String... parts)

Builds a namespaced Redis key with the given arguments.

Parameters:

namespace - the namespace to use

parts - the key parts to be joined

Returns:

an assembled String key

createKey

public static String createKey(String namespace,
                               Iterable<String> parts)

Builds a namespaced Redis key with the given arguments.

Parameters:

namespace - the namespace to use

parts - the key parts to be joined

Returns:

an assembled String key

createBacktrace

public static List<String> createBacktrace(Throwable t)

Creates a Resque backtrace from a Throwable's stack trace. Includes causes.

Parameters:

t - the Exception to use

Returns:

a list of strings that represent how the exception's stacktrace appears.

recreateThrowable

public static Throwable recreateThrowable(String type,
                                          String message,
                                          List<String> backtrace)
                                   throws ParseException,
                                          ClassNotFoundException,
                                          NoSuchConstructorException,
                                          AmbiguousConstructorException,
                                          ReflectiveOperationException

Recreate an exception from a type name, a message and a backtrace (created from JesqueUtils.createBacktrace(Throwable)).

Limitations:
This method cannot recreate Throwables with unusual/custom Constructors.

• If the message is non-null and the cause is null, there must be a Constructor with a single String as it's only parameter.
• If the message is non-null and the cause is non-null, there must be a Constructor with a single String as it's only parameter or a Constructor with a String and a Throwable as its parameters.
• If the message is null and the cause is null, there must be either a no-arg Constructor or a Constructor with a single String as it's only parameter.
• If the message is null and the cause is non-null, there must be either a no-arg Constructor, a Constructor with a single String as its only parameter or a Constructor with a String and a Throwable as its parameters.

Parameters:

type - the String name of the Throwable type

message - the message of the exception

backtrace - the backtrace of the exception

Returns:

a new Throwable of the given type with the given message and given backtrace/causes

Throws:

ParseException - if there is a problem parsing the given backtrace

ClassNotFoundException - if the given type is not available

NoSuchConstructorException - if there is not a common constructor available for the given type

AmbiguousConstructorException - if there is more than one constructor that is viable

InstantiationException - if there is a problem instantiating the given type

IllegalAccessException - if the common constructor is not visible

InvocationTargetException - if the constructor threw an exception

ReflectiveOperationException

See Also:

createBacktrace(Throwable)

instantiateThrowable

protected static Throwable instantiateThrowable(String type,
                                                String message,
                                                Throwable cause,
                                                StackTraceElement[] stes)
                                         throws ClassNotFoundException,
                                                AmbiguousConstructorException,
                                                ReflectiveOperationException,
                                                NoSuchConstructorException

Throws:

ClassNotFoundException

AmbiguousConstructorException

ReflectiveOperationException

NoSuchConstructorException

recreateStackTrace

protected static StackTraceElement[] recreateStackTrace(List<String> bTrace)
                                                 throws ParseException

Throws:

ParseException

map

@SafeVarargs
public static <K,V> Map<K,V> map(Map.Entry<? extends K,? extends V>... entries)

A convenient way of creating a map on the fly.

Type Parameters:

K - the key type

V - the value type

Parameters:

entries - Map.Entry objects to be added to the map

Returns:

a LinkedHashMap with the supplied entries

entry

public static <K,V> Map.Entry<K,V> entry(K key,
                                         V value)

Creates a Map.Entry out of the given key and value. Commonly used in conjunction with map(Entry...)

Type Parameters:

K - the key type

V - the value type

Parameters:

key - the key

value - the value

Returns:

a Map.Entry object with the given key and value

set

@SafeVarargs
public static <K> Set<K> set(K... keys)

Creates a Set out of the given keys

Type Parameters:

K - the key type

Parameters:

keys - the keys

Returns:

a Set containing the given keys

nullSafeEquals

public static boolean nullSafeEquals(Object obj1,
                                     Object obj2)

Test for equality.

Parameters:

obj1 - the first object

obj2 - the second object

Returns:

true if both are null or the two objects are equal

materializeJob

public static Object materializeJob(Job job)
                             throws ClassNotFoundException,
                                    Exception

Materializes a job by assuming the Job.getClassName() is a fully-qualified Java type.

Parameters:

job - the job to materialize

Returns:

the materialized job

Throws:

ClassNotFoundException - if the class could not be found

Exception - if there was an exception creating the object

materializeJob

public static Object materializeJob(Job job,
                                    Map<String,Class<?>> jobTypes)
                             throws UnpermittedJobException,
                                    Exception

Materializes a job by looking up Job.getClassName() in the provided map of job types.

Parameters:

job - the job to materialize

jobTypes - a map of String names to Java types

Returns:

the materialized job

Throws:

UnpermittedJobException - if there was not a non-null mapping in jobTypes for the class name

Exception - if there was an exception creating the object

equal

public static boolean equal(Throwable ex1,
                            Throwable ex2)

This is needed because Throwable doesn't override equals() and object equality is not what we want to test.

Parameters:

ex1 - first Throwable

ex2 - second Throwable

Returns:

true if the two arguments are equal, as we define it.