Example usage for org.apache.commons.collections.map ListOrderedMap isEmpty

Introduction

In this page you can find the example usage for org.apache.commons.collections.map ListOrderedMap isEmpty.

Prototype

public boolean isEmpty() 

Source Link

Usage

From source file:org.apache.ddlutils.io.DatabaseDataIO.java

/**
 * Sorts the given table according to their foreign key order.
 * /*from   w ww . j  a  v a2  s  .  com*/
 * @param tables The tables
 * @return The sorted tables
 */
private List sortTables(Table[] tables) {
    ArrayList result = new ArrayList();
    HashSet processed = new HashSet();
    ListOrderedMap pending = new ListOrderedMap();

    for (int idx = 0; idx < tables.length; idx++) {
        Table table = tables[idx];

        if (table.getForeignKeyCount() == 0) {
            result.add(table);
            processed.add(table);
        } else {
            HashSet waitedFor = new HashSet();

            for (int fkIdx = 0; fkIdx < table.getForeignKeyCount(); fkIdx++) {
                Table waitedForTable = table.getForeignKey(fkIdx).getForeignTable();

                if (!table.equals(waitedForTable)) {
                    waitedFor.add(waitedForTable);
                }
            }
            pending.put(table, waitedFor);
        }
    }

    HashSet newProcessed = new HashSet();

    while (!processed.isEmpty() && !pending.isEmpty()) {
        newProcessed.clear();
        for (Iterator it = pending.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            Table table = (Table) entry.getKey();
            HashSet waitedFor = (HashSet) entry.getValue();

            waitedFor.removeAll(processed);
            if (waitedFor.isEmpty()) {
                it.remove();
                result.add(table);
                newProcessed.add(table);
            }
        }
        processed.clear();

        HashSet tmp = processed;

        processed = newProcessed;
        newProcessed = tmp;
    }
    // the remaining are within circular dependencies
    for (Iterator it = pending.keySet().iterator(); it.hasNext();) {
        result.add(it.next());
    }
    return result;
}

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