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Ant example source code file (Sort.java)

This example Ant source code file (Sort.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Ant tags/keywords

baseresourcecollectionwrapper, delegatedresourcecomparator, iterator, iterator, mutableint, mutableint, myiterator, object, project, resourcecollection, sortedbag, sortedbag, treemap, treemap, util

The Sort.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.tools.ant.types.resources;

import java.util.Stack;
import java.util.TreeMap;
import java.util.Iterator;
import java.util.Collection;
import java.util.Comparator;
import java.util.Collections;
import java.util.AbstractCollection;
import java.util.NoSuchElementException;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.types.DataType;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.resources.comparators.ResourceComparator;
import org.apache.tools.ant.types.resources.comparators.DelegatedResourceComparator;

/**
 * ResourceCollection that sorts another ResourceCollection.
 * @since Ant 1.7
 */
public class Sort extends BaseResourceCollectionWrapper {

    //sorted bag impl. borrowed from commons-collections TreeBag:
    private static class SortedBag extends AbstractCollection {
        private class MutableInt {
            private int value = 0;
        }
        private class MyIterator implements Iterator {
            private Iterator keyIter = t.keySet().iterator();
            private Object current;
            private int occurrence;
            public synchronized boolean hasNext() {
                return occurrence > 0 || keyIter.hasNext();
            }
            public synchronized Object next() {
                if (!hasNext()) {
                    throw new NoSuchElementException();
                }
                if (occurrence == 0) {
                    current = keyIter.next();
                    occurrence = ((MutableInt) t.get(current)).value;
                }
                --occurrence;
                return current;
            }
            public void remove() {
                throw new UnsupportedOperationException();
            }
        }
        private TreeMap t;
        private int size;

        SortedBag(Comparator c) {
            t = new TreeMap(c);
        }
        public synchronized Iterator iterator() {
            return new MyIterator();
        }
        public synchronized boolean add(Object o) {
            if (size < Integer.MAX_VALUE) {
                ++size;
            }
            MutableInt m = (MutableInt) (t.get(o));
            if (m == null) {
                m = new MutableInt();
                t.put(o, m);
            }
            m.value++;
            return true;
        }
        public synchronized int size() {
            return size;
        }
    }

    private DelegatedResourceComparator comp = new DelegatedResourceComparator();

    /**
     * Sort the contained elements.
     * @return a Collection of Resources.
     */
    protected synchronized Collection getCollection() {
        ResourceCollection rc = getResourceCollection();
        Iterator iter = rc.iterator();
        if (!(iter.hasNext())) {
            return Collections.EMPTY_SET;
        }
        SortedBag b = new SortedBag(comp);
        while (iter.hasNext()) {
            b.add(iter.next());
        }
        return b;
    }

    /**
     * Add a ResourceComparator to this Sort ResourceCollection.
     * If multiple ResourceComparators are added, they will be processed in LIFO order.
     * @param c the ResourceComparator to add.
     */
    public synchronized void add(ResourceComparator c) {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        comp.add(c);
        FailFast.invalidate(this);
    }

    /**
     * Overrides the BaseResourceCollectionContainer version
     * to recurse on nested ResourceComparators.
     * @param stk the stack of data types to use (recursively).
     * @param p   the project to use to dereference the references.
     * @throws BuildException on error.
     */
    protected synchronized void dieOnCircularReference(Stack stk, Project p)
        throws BuildException {
        if (isChecked()) {
            return;
        }
        if (isReference()) {
            super.dieOnCircularReference(stk, p);
        } else {
            DataType.invokeCircularReferenceCheck(comp, stk, p);
            setChecked(true);
        }
    }

}

Other Ant examples (source code examples)

Here is a short list of links related to this Ant Sort.java source code file:

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