Ant example source code file (BaseResourceCollectionContainer.java)

This example Ant source code file (BaseResourceCollectionContainer.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

arraylist, baseresourcecollectioncontainer, baseresourcecollectioncontainer, buildexception, buildexception, collection, collection, datatype, io, iterator, iterator, list, object, resourcecollection, stringbuffer, util

The BaseResourceCollectionContainer.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.io.File;
import java.util.List;
import java.util.Stack;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

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;

/**
 * Base class for ResourceCollections that nest multiple ResourceCollections.
 * @since Ant 1.7
 */
public abstract class BaseResourceCollectionContainer
    extends DataType implements ResourceCollection, Cloneable {
    private List rc = new ArrayList();
    private Collection coll = null;
    private boolean cache = true;

    /**
     * Set whether to cache collections.
     * @param b boolean cache flag.
     */
    public synchronized void setCache(boolean b) {
        cache = b;
    }

    /**
     * Learn whether to cache collections. Default is <code>true.
     * @return boolean cache flag.
     */
    public synchronized boolean isCache() {
        return cache;
    }

    /**
     * Clear the container.
     * @throws BuildException on error.
     */
    public synchronized void clear() throws BuildException {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        rc.clear();
        FailFast.invalidate(this);
        coll = null;
        setChecked(false);
    }

    /**
     * Add a ResourceCollection to the container.
     * @param c the ResourceCollection to add.
     * @throws BuildException on error.
     */
    public synchronized void add(ResourceCollection c) throws BuildException {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        if (c == null) {
            return;
        }
        rc.add(c);
        FailFast.invalidate(this);
        coll = null;
        setChecked(false);
    }

    /**
     * Add the Collection of ResourceCollections to the container.
     * @param c the Collection whose elements to add.
     * @throws BuildException on error.
     */
    public synchronized void addAll(Collection c) throws BuildException {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        try {
            for (Iterator i = c.iterator(); i.hasNext();) {
                add((ResourceCollection) i.next());
            }
        } catch (ClassCastException e) {
            throw new BuildException(e);
        }
    }

    /**
     * Fulfill the ResourceCollection contract. The Iterator returned
     * will throw ConcurrentModificationExceptions if ResourceCollections
     * are added to this container while the Iterator is in use.
     * @return a "fail-fast" Iterator.
     */
    public final synchronized Iterator iterator() {
        if (isReference()) {
            return ((BaseResourceCollectionContainer) getCheckedRef()).iterator();
        }
        dieOnCircularReference();
        return new FailFast(this, cacheCollection().iterator());
    }

    /**
     * Fulfill the ResourceCollection contract.
     * @return number of elements as int.
     */
    public synchronized int size() {
        if (isReference()) {
            return ((BaseResourceCollectionContainer) getCheckedRef()).size();
        }
        dieOnCircularReference();
        return cacheCollection().size();
    }

    /**
     * Fulfill the ResourceCollection contract.
     * @return whether this is a filesystem-only resource collection.
     */
    public synchronized boolean isFilesystemOnly() {
        if (isReference()) {
            return ((BaseResourceCollectionContainer) getCheckedRef()).isFilesystemOnly();
        }
        dieOnCircularReference();
        //first the easy way, if all children are filesystem-only, return true:
        boolean goEarly = true;
        for (Iterator i = rc.iterator(); goEarly && i.hasNext();) {
            goEarly &= ((ResourceCollection) i.next()).isFilesystemOnly();
        }
        if (goEarly) {
            return true;
        }
        /* now check each Resource in case the child only
           lets through files from any children IT may have: */
        for (Iterator i = cacheCollection().iterator(); i.hasNext();) {
            if (!(i.next() instanceof FileResource)) {
                return false;
            }
        }
        return true;
    }

    /**
     * Overrides the version of DataType to recurse on all DataType
     * child elements that may have been added.
     * @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 {
            for (Iterator i = rc.iterator(); i.hasNext();) {
                Object o = i.next();
                if (o instanceof DataType) {
                    stk.push(o);
                    invokeCircularReferenceCheck((DataType) o, stk, p);
                    stk.pop();
                }
            }
            setChecked(true);
        }
    }

    /**
     * Get the nested ResourceCollections.
     * @return List.
     */
    protected final synchronized List getResourceCollections() {
        dieOnCircularReference();
        return Collections.unmodifiableList(rc);
    }

    /**
     * Template method for subclasses to return a Collection object of Resources.
     * @return Collection.
     */
    protected abstract Collection getCollection();

    /**
     * Implement clone.  The set of nested resource
     * collections is shallowly cloned.
     * @return a cloned instance.
     */
    public Object clone() {
        try {
            BaseResourceCollectionContainer c
                = (BaseResourceCollectionContainer) super.clone();
            c.rc = new ArrayList(rc);
            c.coll = null;
            return c;
        } catch (CloneNotSupportedException e) {
            throw new BuildException(e);
        }
   }

    /**
     * Format this BaseResourceCollectionContainer as a String.
     * @return a descriptive <code>String.
     */
    public synchronized String toString() {
        if (isReference()) {
            return getCheckedRef().toString();
        }
        if (cacheCollection().size() == 0) {
            return "";
        }
        StringBuffer sb = new StringBuffer();
        for (Iterator i = coll.iterator(); i.hasNext();) {
            if (sb.length() > 0) {
                sb.append(File.pathSeparatorChar);
            }
            sb.append(i.next());
        }
        return sb.toString();
    }

    private synchronized Collection cacheCollection() {
        if (coll == null || !isCache()) {
            coll = getCollection();
        }
        return coll;
    }

}