/*
* 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.AbstractCollection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Stack;
import java.util.stream.Collectors;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.DataType;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.util.CollectionUtils;
/**
* Generic ResourceCollection: Either stores nested ResourceCollections,
* making no attempt to remove duplicates, or references another ResourceCollection.
* @since Ant 1.7
*/
public class Resources extends DataType implements ResourceCollection {
/** static empty ResourceCollection */
public static final ResourceCollection NONE = new ResourceCollection() {
@Override
public boolean isFilesystemOnly() {
return true;
}
@Override
public Iterator<Resource> iterator() {
return EMPTY_ITERATOR;
}
@Override
public int size() {
return 0;
}
};
/** static empty Iterator */
public static final Iterator<Resource> EMPTY_ITERATOR = new Iterator<Resource>() {
@Override
public Resource next() {
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
return false;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
private class MyCollection extends AbstractCollection<Resource> {
private Collection<Resource> cached;
MyCollection() {
}
@Override
public int size() {
return getCache().size();
}
@Override
public Iterator<Resource> iterator() {
return getCache().iterator();
}
private synchronized Collection<Resource> getCache() {
Collection<Resource> coll = cached;
if (coll == null) {
coll = CollectionUtils.asCollection(new MyIterator());
if (cache) {
cached = coll;
}
}
return coll;
}
private class MyIterator implements Iterator<Resource> {
private Iterator<ResourceCollection> rci = getNested().iterator();
private Iterator<Resource> ri = null;
@Override
public boolean hasNext() {
boolean result = ri != null && ri.hasNext();
while (!result && rci.hasNext()) {
ri = rci.next().iterator();
result = ri.hasNext();
}
return result;
}
@Override
public Resource next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
return ri.next();
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
}
private List<ResourceCollection> rc;
private Collection<Resource> coll;
private boolean cache = false;
/**
* Create a new Resources.
*/
public Resources() {
}
/**
* Create a new Resources.
* @since Ant 1.8
*/
public Resources(Project project) {
setProject(project);
}
/**
* Set whether to cache collections.
* @param b boolean cache flag.
* @since Ant 1.8.0
*/
public synchronized void setCache(boolean b) {
cache = b;
}
/**
* Add a ResourceCollection.
* @param c the ResourceCollection to add.
*/
public synchronized void add(ResourceCollection c) {
if (isReference()) {
throw noChildrenAllowed();
}
if (c == null) {
return;
}
if (rc == null) {
rc = Collections.synchronizedList(new ArrayList<>());
}
rc.add(c);
invalidateExistingIterators();
coll = null;
setChecked(false);
}
/**
* Fulfill the ResourceCollection contract.
* @return an Iterator of Resources.
*/
@Override
public synchronized Iterator<Resource> iterator() {
if (isReference()) {
return getRef().iterator();
}
validate();
return new FailFast(this, coll.iterator());
}
/**
* Fulfill the ResourceCollection contract.
* @return number of elements as int.
*/
@Override
public synchronized int size() {
if (isReference()) {
return getRef().size();
}
validate();
return coll.size();
}
/**
* Fulfill the ResourceCollection contract.
* @return true if all Resources represent files.
*/
@Override
public boolean isFilesystemOnly() {
if (isReference()) {
return getRef().isFilesystemOnly();
}
validate();
return getNested().stream()
.allMatch(ResourceCollection::isFilesystemOnly);
}
/**
* Format this <code>Resources</code> as a String.
* @return a descriptive <code>String</code>.
*/
@Override
public synchronized String toString() {
if (isReference()) {
return getCheckedRef().toString();
}
validate();
if (coll == null || coll.isEmpty()) {
return "";
}
return coll.stream().map(Object::toString)
.collect(Collectors.joining(File.pathSeparator));
}
/**
* 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.
*/
@Override
protected void dieOnCircularReference(Stack<Object> stk, Project p)
throws BuildException {
if (isChecked()) {
return;
}
if (isReference()) {
super.dieOnCircularReference(stk, p);
} else {
for (ResourceCollection resourceCollection : getNested()) {
if (resourceCollection instanceof DataType) {
pushAndInvokeCircularReferenceCheck((DataType) resourceCollection, stk, p);
}
}
setChecked(true);
}
}
/**
* Allow subclasses to notify existing Iterators they have experienced concurrent modification.
*/
protected void invalidateExistingIterators() {
FailFast.invalidate(this);
}
/**
* Resolves references, allowing any ResourceCollection.
* @return the referenced ResourceCollection.
*/
private ResourceCollection getRef() {
return getCheckedRef(ResourceCollection.class, "ResourceCollection");
}
private synchronized void validate() {
dieOnCircularReference();
coll = (coll == null) ? new MyCollection() : coll;
}
private synchronized List<ResourceCollection> getNested() {
return rc == null ? Collections.<ResourceCollection> emptyList() : rc;
}
}