net.cnri.repository.util

Class CollectionUtil

java.lang.Object

net.cnri.repository.util.CollectionUtil

public class CollectionUtil
extends java.lang.Object

Convenience utilities for Collections, especially Iterators and CloseableIterators.

Constructor Summary

Constructors

Constructor and Description
CollectionUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> void	addAllFromIterator(java.util.Collection<T> collection, CloseableIterator<T> iter) Add all the elements of a given CloseableIterator to a given Collection.
static <T> java.util.List<T>	asList(CloseableIterator<T> iter) Return the elements of a given CloseableIterator as a List.
static <T> java.util.Set<T>	asSet(CloseableIterator<T> iter) Return the elements of a given CloseableIterator as a Set.
static java.util.Set<java.lang.String>	difference(java.util.Set<java.lang.String> a, java.util.Set<java.lang.String> b)
static <T> java.lang.Iterable<T>	forEach(java.util.Iterator<T> iter) A convenience method to use an iterator in a for-each loop.
static java.util.Set<java.lang.String>	intersection(java.util.List<java.util.Set<java.lang.String>> sets)
static java.util.Set<java.lang.String>	intersection(java.util.Set<java.lang.String> a, java.util.Set<java.lang.String> b)
static java.util.Set<java.lang.String>	union(java.util.List<java.util.Set<java.lang.String>> sets)

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtil

public CollectionUtil()

Method Detail

difference

public static java.util.Set<java.lang.String> difference(java.util.Set<java.lang.String> a,
                                         java.util.Set<java.lang.String> b)

Parameters:

a -

b -

Returns:

a - b

union

public static java.util.Set<java.lang.String> union(java.util.List<java.util.Set<java.lang.String>> sets)

intersection

public static java.util.Set<java.lang.String> intersection(java.util.List<java.util.Set<java.lang.String>> sets)

intersection

public static java.util.Set<java.lang.String> intersection(java.util.Set<java.lang.String> a,
                                           java.util.Set<java.lang.String> b)

addAllFromIterator

public static <T> void addAllFromIterator(java.util.Collection<T> collection,
                          CloseableIterator<T> iter)
                               throws RepositoryException

Add all the elements of a given CloseableIterator to a given Collection. The CloseableIterator will be closed, and unchecked exceptions will be properly propagated.

Parameters:

collection - a collection to be added to

iter - an iterator, the elements of which will be added to the collection

Throws:

RepositoryException

asList

public static <T> java.util.List<T> asList(CloseableIterator<T> iter)
                                throws RepositoryException

Return the elements of a given CloseableIterator as a List. The CloseableIterator will be closed, and unchecked exceptions will be properly propagated.

Parameters:

iter - an iterator

Throws:

RepositoryException

asSet

public static <T> java.util.Set<T> asSet(CloseableIterator<T> iter)
                              throws RepositoryException

Return the elements of a given CloseableIterator as a Set. The CloseableIterator will be closed, and unchecked exceptions will be properly propagated.

Parameters:

iter - an iterator

Throws:

RepositoryException

forEach

public static <T> java.lang.Iterable<T> forEach(java.util.Iterator<T> iter)

A convenience method to use an iterator in a for-each loop. To correctly use with a CloseableIterator:

        CloseableIterator<DataElement> iter = dobj.listDataElements();
        try {   
            for(DataElement element : CollectionUtil.forEach(iter)) {
                // ...
            }
        } catch (UncheckedRepositoryException e) {
            e.throwCause();
        } finally {
            iter.close();
        }
 

Note that the returned Iterable does not allow its iterator() method to return a fresh iterator each time; the iteration is once-only.

Parameters:

iter - an iterator