Example usage for java.util Collection iterator

Introduction

In this page you can find the example usage for java.util Collection iterator.

Prototype

Iterator<E> iterator();

Source Link

Document

Returns an iterator over the elements in this collection.

Usage

From source file:Main.java

public static String collectionToSlashString(Collection<?> collection) {
    if (collection != null && collection.size() > 0) {
        StringBuilder sb = new StringBuilder();
        Object obj = null;//  www .j  ava 2 s  . c o m
        for (Iterator<?> iterator = collection.iterator(); iterator.hasNext();) {
            obj = iterator.next();
            sb.append(obj.toString());
            if (iterator.hasNext()) {
                sb.append("/");
            }
        }
        return sb.toString();
    } else {
        return "";
    }
}

From source file:Main.java

/**
 * Join a bunch of objects into a string delimited by the separator
 *
 * @param sep//from  w w w  . ja v a 2  s .c  o m
 * @param c
 * @return
 */
public static String join(final String sep, final Collection<? extends Object> c) {
    if (c == null) {
        return null;
    }
    if (c.size() == 1) {
        return String.valueOf(c.iterator().next());
    }
    if (c.size() == 0) {
        return "";
    }
    final StringBuilder sb = new StringBuilder();
    String s = "";
    for (final Object o : c) {
        sb.append(s).append(String.valueOf(o));
        s = sep;
    }
    return sb.toString();
}

From source file:Main.java

/**
 * Joins the elements of the provided <code>Collection</code> into
 * a single String containing the provided elements.
 *
 * No delimiter is added before or after the list. Null objects or empty
 * strings within the iteration are represented by empty strings.
 *
 * See the examples here: {@link #join(Object[],char)}. 
 *
 * @param collection  the <code>Collection</code> of values to join together, may be null
 * @param separator  the separator character to use
 * @return the joined String, <code>null</code> if null iterator input
 * @since 2.3//from   w w w. j  a  v a2  s  .c o  m
 */
public static String join(Collection collection, char separator) {
    if (collection == null) {
        return null;
    }
    return join(collection.iterator(), separator);
}

From source file:Main.java

public static String[] asArray(Object object) {
    if (object == null) {
        return null;
    }//from  w  w  w  . j  a v  a  2 s.c o  m

    Class componentType = object.getClass().getComponentType();

    if (String.class.equals(componentType)) {
        return (String[]) object;
    } else if (componentType != null) {
        Object[] objects = (Object[]) object;
        String[] result = new String[objects.length];
        for (int i = 0; i < objects.length; i++) {
            Object o = objects[i];
            if (o == null) {
                continue;
            }

            result[i] = o.toString();
        }

        return result;
    } else if (object instanceof Collection) {
        Collection collection = (Collection) object;
        String[] result = new String[collection.size()];
        Iterator iterator = collection.iterator();

        for (int i = 0; i < result.length; i++) {
            Object next = iterator.next();
            if (next == null) {
                continue;
            }

            result[i] = next.toString();
        }

        return result;
    } else {
        String string = object.toString().trim();
        String[] split = string.split("\\s*,\\s*");
        return split;
    }
}

From source file:Main.java

public static <T> T getFirst(Collection<T> collection) {
    if (isEmpty(collection)) {
        return null;
    }/*from w  w  w.  j  a v  a  2 s. com*/
    if (collection instanceof List) {
        return ((List<T>) collection).get(0);
    }
    return collection.iterator().next();
}

From source file:Main.java

/**
 * <p>Joins the elements of the provided <code>Collection</code> into
 * a single String containing the provided elements.</p>
 *
 * <p>No delimiter is added before or after the list.
 * A <code>null</code> separator is the same as an empty String ("").</p>
 *
 * <p>See the examples here: {@link #join(Object[],String)}. </p>
 *
 * @param collection  the <code>Collection</code> of values to join together, may be null
 * @param separator  the separator character to use, null treated as ""
 * @return the joined String, <code>null</code> if null iterator input
 * @since 2.3/*from www.  j a  v a 2  s.c  o m*/
 */
public static String join(Collection collection, String separator) {
    if (collection == null) {
        return null;
    }
    return join(collection.iterator(), separator);
}

From source file:Main.java

@SuppressWarnings("rawtypes")
public static boolean hasUniqueObject(Collection<?> collection) {
    if (isEmpty(collection)) {
        return false;
    }/*from w  ww .j a  v a 2  s .  c o  m*/
    boolean hasCandidate = false;
    Object candidate = null;
    for (Iterator it = collection.iterator(); it.hasNext();) {
        Object elem = it.next();
        if (!hasCandidate) {
            hasCandidate = true;
            candidate = elem;
        } else if (candidate != elem) {
            return false;
        }
    }
    return true;
}

From source file:Main.java

/**
 * Find a single value of the given type in the given Collection.
 * @param collection the Collection to search
 * @param type the type to look for/*from   w  ww.  j ava  2 s. c o m*/
 * @return a value of the given type found if there is a clear match,
 * or <code>null</code> if none or more than one such value found
 */
public static Object findValueOfType(Collection collection, Class type) {
    if (isEmpty(collection)) {
        return null;
    }
    Object value = null;
    for (Iterator it = collection.iterator(); it.hasNext();) {
        Object obj = it.next();
        if (type == null || type.isInstance(obj)) {
            if (value != null) {
                // More than one value found... no clear single value.
                return null;
            }
            value = obj;
        }
    }
    return value;
}

From source file:Main.java

public static <T> List<Collection<T>> splitCollection(Collection<T> col, int numLists)
        throws InstantiationException, IllegalAccessException {
    List<Collection<T>> lstReturn = new ArrayList<Collection<T>>();
    Iterator<T> iter = col.iterator();

    for (int c = 0; c < numLists; c++) {
        Collection<T> temp = col.getClass().newInstance();
        lstReturn.add(temp);/*ww  w.  ja va 2 s . co  m*/
    }

    while (iter.hasNext()) {
        for (int collectionIndex = 0; collectionIndex < numLists; collectionIndex++) {
            if (iter.hasNext()) {
                Collection<T> current = lstReturn.get(collectionIndex);
                T value = iter.next();
                current.add(value);
            }
        }
    }

    return lstReturn;
}

From source file:com.projity.util.DataUtils.java

/**
 * Apply a closure to one of the collections: if all is true, then use the allList, otherwise
 * use the nodeList, and extract only the impls of the type clazz (or subclasses of clazz)
 * @param closure/*from  w ww  .  j  a va 2  s  .  com*/
 * @param all
 * @param allList
 * @param nodeList
 * @param clazz
 */
public static void forAllDo(Closure closure, boolean all, Collection allList, Collection nodeList,
        Class clazz) {
    forAllDo(closure, all, allList.iterator(), nodeList, clazz);
}