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

/**
 * Transfer up to 'maxElems' elements from the source to the destination.
 *///from  w w  w  . j  a  va2s  .  c  om
public static void transfer(Collection source, Collection dest, int maxElems) {
    int j = 0;
    for (Iterator i = source.iterator(); i.hasNext() && j < maxElems; j++) {
        dest.add(i.next());
        i.remove();
    }
}

From source file:Main.java

public static <E> void print(Collection<E> collections) {
    StringBuilder builder = new StringBuilder();
    for (Iterator<E> iterator = collections.iterator(); iterator.hasNext();) {
        E e = iterator.next();/*w  w  w .j a  va 2  s.co  m*/
        if (e == null) {
            builder.append(",null");
        } else {
            builder.append("," + e.toString());
        }
    }

    System.out.println(builder.substring(1, builder.length()));
}

From source file:Main.java

/**
 * Answer the junction between a and b. Answer is of the same type as a.
 * /*from  www .j a v  a  2s.co  m*/
 * @param a
 * @param b
 * @return
 */
public static Collection junction(Collection a, Collection b) {
    Collection answer = createCollection(a);
    for (Iterator i = a.iterator(); i.hasNext();) {
        Object oa = i.next();
        for (Iterator k = b.iterator(); k.hasNext();) {
            Object ob = k.next();
            if (oa.equals(ob)) {
                answer.add(oa);
            }
        }
    }
    return answer;
}

From source file:Main.java

/**
 * Prints each object in the collection with commas between them.
 * Nulls will print as "null".  A null collection will cause NPE.
 *//*from   w ww .j  ava 2s . c  o m*/
public static String collectionToString(Collection col) {
    StringBuffer outputString = new StringBuffer(100);
    boolean firstItem = true;
    Iterator it = col.iterator();
    while (it.hasNext()) {
        if (!firstItem)
            outputString.append(", ");
        outputString.append(it.next());
        firstItem = false;
    }
    return outputString.toString();
}

From source file:Main.java

/**
 * An flexible alternative for converting a Collection to a String.
 *
 * @param c The Collection to convert to a String
 * @param start The String to place at the beginning of the returned String
 * @param separator The String to place in between elements of the Collection c.
 * @param end The String to place at the end of the returned String
 * @return A String which starts with 'start', followed by the elements in the Collection c separated by 'separator',
 * ending with 'end'./*w  w  w.j a  va2 s .  c om*/
 */
@SuppressWarnings("rawtypes")
public static String toString(Collection c, String start, String separator, String end) {
    Iterator i = c.iterator();
    StringBuilder myString = new StringBuilder();

    if (start != null) {
        myString.append(start);
    }

    boolean first = true;
    while (i.hasNext()) {
        if (!first) {
            myString.append(separator);
        }
        myString.append(i.next().toString());
        first = false;
    }

    if (end != null) {
        myString.append(end);
    }

    return myString.toString();
}

From source file:Main.java

public static <T> Collection<T> reverse(final Collection<T> collection) {
    final LinkedList<T> newCollection = new LinkedList<>();
    final Iterator<T> i = collection.iterator();
    while (i.hasNext()) {
        newCollection.addFirst(i.next());
    }/*from w w  w  .jav  a 2  s  . c  o m*/
    return newCollection;
}

From source file:Main.java

@SuppressWarnings({ "rawtypes", "unchecked" })
public static Map getCardinalityMap(final Collection coll) {
    final Map count = new HashMap();
    for (final Iterator it = coll.iterator(); it.hasNext();) {
        final Object obj = it.next();
        final Integer c = (Integer) (count.get(obj));
        if (c == null) {
            count.put(obj, INTEGER_ONE);
        } else {//from   w  w w . j ava  2 s.  c  o  m
            count.put(obj, new Integer(c.intValue() + 1));
        }
    }
    return count;
}

From source file:Main.java

public static StringBuilder join(CharSequence separator, Collection<?> col) {
    final StringBuilder result = new StringBuilder();
    if (col != null) {
        for (Iterator<?> it = col.iterator(); it.hasNext();) {
            result.append(it.next());//  w w  w .j av a2  s . c om
            if (it.hasNext()) {
                result.append(separator);
            }
        }
    }
    return result;
}

From source file:Main.java

public static <T> T first(Collection<T> collection) {
    if (collection == null || collection.isEmpty()) {
        return null;
    }// w  ww  .  j  av a  2  s. co  m
    return collection.iterator().next();
}

From source file:Main.java

public static <T> Set<String> toStringSet(Collection<T> a_values)
/*     */ {/*  ww w.j  a  v  a 2s  .com*/
    /* 443 */Set values = new HashSet();
    /*     */
    /* 445 */for (Iterator i$ = a_values.iterator(); i$.hasNext();) {
        Object value = i$.next();
        /*     */
        /* 447 */values.add(value.toString());
        /*     */}
    /*     */
    /* 450 */return values;
    /*     */}