org.hypergraphdb.util
Class HGUtils

java.lang.Object
  org.hypergraphdb.util.HGUtils

public class HGUtils
extends java.lang.Object

The mandatory bag of static utility method class.

Author:

Borislav Iordanov

Constructor Summary

HGUtils()

Method Summary

static void	closeNoException(HGSearchResult<?> rs)
static boolean	eq(byte[] left, byte[] right)
static boolean	eq(java.lang.Object[] left, java.lang.Object[] right) Compare two arrays for equality.
static boolean	eq(java.lang.Object left, java.lang.Object right) Compare two objects for equality, checking for null values as well.
static java.lang.Throwable	getRootCause(java.lang.Throwable t)
static int	hashIt(java.lang.Object o) Return an object's hash code or 0 if the object is null.
static int	hashThem(java.lang.Object one, java.lang.Object two) Return a composite hash code of two objects.
static boolean	isEmpty(java.lang.String s)
static <T> java.lang.Class<T>	loadClass(java.lang.String classname)
static void	logCallStack(java.io.PrintStream out)
static void	printStackTrace(java.lang.StackTraceElement[] trace, java.io.PrintStream out)
static java.lang.String	printStackTrace(java.lang.Throwable t) Print the full stack trace of a Throwable object into a string buffer and return the corresponding string.
static <T> long	queryBatchProcess(HGQuery<T> query, Mapping<T,java.lang.Boolean> F, int batchSize, T startAfter, long first) Process a potentially large query result in batches where each batch is a encapsulated in a single transaction.
static java.lang.RuntimeException	throwRuntimeException(java.lang.Throwable t)
static HGHandle[]	toHandleArray(HGLink link)
static void	wrapAndRethrow(java.lang.Throwable t)

Methods inherited from class java.lang.Object

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

Constructor Detail

HGUtils

public HGUtils()

Method Detail

isEmpty

public static boolean isEmpty(java.lang.String s)

throwRuntimeException

public static java.lang.RuntimeException throwRuntimeException(java.lang.Throwable t)

getRootCause

public static java.lang.Throwable getRootCause(java.lang.Throwable t)

eq

public static boolean eq(java.lang.Object left,
                         java.lang.Object right)

Compare two objects for equality, checking for null values as well.

eq

public static boolean eq(java.lang.Object[] left,
                         java.lang.Object[] right)

Compare two arrays for equality. This will perform a deep comparison, return true if and only if all elements of the passed in arrays are equal.

eq

public static boolean eq(byte[] left,
                         byte[] right)

hashIt

public static int hashIt(java.lang.Object o)

Return an object's hash code or 0 if the object is null.

hashThem

public static int hashThem(java.lang.Object one,
                           java.lang.Object two)

Return a composite hash code of two objects.

printStackTrace

public static java.lang.String printStackTrace(java.lang.Throwable t)

Print the full stack trace of a Throwable object into a string buffer and return the corresponding string.

printStackTrace

public static void printStackTrace(java.lang.StackTraceElement[] trace,
                                   java.io.PrintStream out)

logCallStack

public static void logCallStack(java.io.PrintStream out)

closeNoException

public static void closeNoException(HGSearchResult<?> rs)

wrapAndRethrow

public static void wrapAndRethrow(java.lang.Throwable t)

loadClass

public static <T> java.lang.Class<T> loadClass(java.lang.String classname)
                                    throws java.lang.ClassNotFoundException

Throws:

java.lang.ClassNotFoundException

toHandleArray

public static HGHandle[] toHandleArray(HGLink link)

queryBatchProcess

public static <T> long queryBatchProcess(HGQuery<T> query,
                                         Mapping<T,java.lang.Boolean> F,
                                         int batchSize,
                                         T startAfter,
                                         long first)

Process a potentially large query result in batches where each batch is a encapsulated in a single transaction. It is assumed that the result of the query is a HGRandomAccessResult so it is possible to quickly position at the beginning of the next batch.

The startAfter and first parameters define a starting point for the process. Use either one of them, but not both.

Type Parameters:

T -

Parameters:

query - The query that produces the result set to be scanned.

F - The function to perform on that query. The function takes a query result item and return a boolean which indicates whether to continue processing (if true) or stop (if false).

batchSize - The number of result items to encapsulate in a single transaction.

startAfter - Start processing at the first element after this parameter.

first - A 1-based index of the first element to process.

Returns:

The total number of elements processed.