/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
* (c) 2001 - 2013 OpenPlans
* This code is licensed under the GPL 2.0 license, available at the root
* application directory.
*/
package org.geoserver.csw.feature;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.FeatureIterator;
import org.geotools.feature.collection.DelegateFeatureIterator;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.util.NullProgressListener;
import org.opengis.feature.Feature;
import org.opengis.feature.type.FeatureType;
/**
* A derivation of GeoTools {@link org.geotools.feature.collection.AbstractFeatureCollection} that
* works on top of complex features
*
* @author Jody Garnett (Refractions Research Inc)
* @author Andrea Aime - GeoSolutions
*
* @source $URL$
*/
public abstract class AbstractFeatureCollection<T extends FeatureType, F extends Feature> implements
FeatureCollection<T, F> {
/**
* id used when serialized to gml
*/
protected String id;
protected T schema;
protected AbstractFeatureCollection(T memberType) {
this.id = id == null ? "featureCollection" : id;
this.schema = memberType;
}
//
// FeatureCollection - Feature Access
//
@SuppressWarnings("unchecked")
public FeatureIterator<F> features() {
FeatureIterator iter = new DelegateFeatureIterator(openIterator());
getOpenIterators().add(iter);
return iter;
}
/**
* Clean up after any resources associated with this iteartor in a manner similar to JDO
* collections. </p> Example (safe) use:
*
* <pre>
* <code>
* Iterator iterator = collection.iterator();
* try {
* for( Iterator i=collection.iterator(); i.hasNext();){
* Feature feature = (Feature) i.hasNext();
* System.out.println( feature.getID() );
* }
* }
* finally {
* collection.close( iterator );
* }
* </code>
* </pre>
*
* </p>
*
* @param close
*/
@SuppressWarnings("unchecked")
final public void close(Iterator close) {
if (close == null)
return;
try {
closeIterator(close);
} catch (Throwable e) {
// TODO Log e = ln
} finally {
open.remove(close);
}
}
public void close(FeatureIterator<F> close) {
if (close != null) {
close.close();
}
}
/**
* Open a resource based Iterator, we will call close( iterator ).
* <p>
* Please subclass to provide your own iterator for the the ResourceCollection, note
* <code>iterator()</code> is implemented to call <code>open()</code> and track the results in
* for later <code>purge()</code>.
*
* @return Iterator based on resource use
*/
abstract protected Iterator<F> openIterator();
/**
* Please override to cleanup after your own iterators, and any used resources.
* <p>
* As an example if the iterator was working off a File then the inputstream should be closed.
* </p>
* <p>
* Subclass must call super.close( close ) to allow the list of open iterators to be adjusted.
* </p>
*
* @param close Iterator, will not be <code>null</code>
*/
abstract protected void closeIterator(Iterator<F> close);
/**
* Close any outstanding resources released by this resources.
* <p>
* This method should be used with great caution, it is however available to allow the use of
* the ResourceCollection with algorthims that are unaware of the need to close iterators after
* use.
* </p>
* <p>
* Example of using a normal Collections utility method:
*
* <pre>
* <code>
* Collections.sort( collection );
* collection.purge();
* </code>
* </pre>
*/
@SuppressWarnings("unchecked")
public void purge() {
for (Iterator i = open.iterator(); i.hasNext();) {
Object resource = i.next();
if (resource instanceof Iterator) {
Iterator resourceIterator = (Iterator) resource;
try {
closeIterator(resourceIterator);
} catch (Throwable e) {
// TODO: Log e = ln
} finally {
i.remove();
}
}
}
}
/**
* Removes all of the elements from this collection (optional operation).
*
* @throws UnsupportedOperationException if the <tt>clear</tt> method is not supported by this
* collection.
*/
public void clear() {
Iterator<F> e = iterator();
try {
while (e.hasNext()) {
e.next();
e.remove();
}
} finally {
close(e);
}
}
/**
* Returns <tt>true</tt> if this collection contains the specified element. <tt></tt>.
* <p>
*
* This implementation iterates over the elements in the collection, checking each element in
* turn for equality with the specified element.
*
* @param o object to be checked for containment in this collection.
* @return <tt>true</tt> if this collection contains the specified element.
*/
public boolean contains(Object o) {
Iterator<F> e = null;
try {
e = iterator();
if (o == null) {
while (e.hasNext())
if (e.next() == null)
return true;
} else {
while (e.hasNext())
if (o.equals(e.next()))
return true;
}
return false;
} finally {
close(e);
}
}
/**
* Returns <tt>true</tt> if this collection contains all of the elements in the specified
* collection.
* <p>
*
* @param c collection to be checked for containment in this collection.
* @return <tt>true</tt> if this collection contains all of the elements in the specified
* collection.
* @throws NullPointerException if the specified collection is null.
*
* @see #contains(Object)
*/
public boolean containsAll(Collection<?> c) {
Iterator<?> e = c.iterator();
try {
while (e.hasNext())
if (!contains(e.next()))
return false;
return true;
} finally {
close(e);
}
}
//
// Contents
//
//
/** Set of open resource iterators */
@SuppressWarnings("unchecked")
protected final Set open = new HashSet<Iterator<F>>();
/**
* Returns the set of open iterators.
* <p>
* Contents are a mix of Iterator<F> and FeatureIterator
*/
@SuppressWarnings("unchecked")
final public Set getOpenIterators() {
return open;
}
/**
* Please implement!
* <p>
* Note: If you return a ResourceIterator, the default implemntation of close( Iterator ) will
* know what to do.
*
*/
@SuppressWarnings("unchecked")
final public Iterator<F> iterator() {
Iterator<F> iterator = openIterator();
getOpenIterators().add(iterator);
return iterator;
}
/**
* @return <tt>true</tt> if this collection contains no elements.
*/
public boolean isEmpty() {
Iterator<F> iterator = iterator();
try {
return !iterator.hasNext();
} finally {
close(iterator);
}
}
/**
* Array of all the elements.
*
* @return an array containing all of the elements in this collection.
*/
public Object[] toArray() {
Object[] result = new Object[size()];
Iterator<F> e = null;
try {
e = iterator();
for (int i = 0; e.hasNext(); i++)
result[i] = e.next();
return result;
} finally {
close(e);
}
}
@SuppressWarnings("unchecked")
public <T2> T2[] toArray(T2[] a) {
int size = size();
if (a.length < size) {
a = (T2[]) java.lang.reflect.Array.newInstance(a.getClass().getComponentType(), size);
}
Iterator<F> it = iterator();
try {
Object[] result = a;
for (int i = 0; i < size; i++)
result[i] = it.next();
if (a.length > size)
a[size] = null;
return a;
} finally {
close(it);
}
}
public void accepts(org.opengis.feature.FeatureVisitor visitor,
org.opengis.util.ProgressListener progress) {
Iterator<F> iterator = null;
if (progress == null)
progress = new NullProgressListener();
try {
float size = size();
float position = 0;
progress.started();
for (iterator = iterator(); !progress.isCanceled() && iterator.hasNext();) {
if (size > 0)
progress.progress(position++ / size);
try {
Feature feature = (Feature) iterator.next();
visitor.visit(feature);
} catch (Exception erp) {
progress.exceptionOccurred(erp);
}
}
} finally {
progress.complete();
close(iterator);
}
}
public String getID() {
return id;
}
public T getSchema() {
return schema;
}
@Override
public int size() {
FeatureIterator<F> fi = null;
int count = 0;
try {
fi = features();
while (fi.hasNext()) {
fi.next();
count++;
}
} finally {
if (fi != null) {
fi.close();
}
}
return count;
}
@Override
public ReferencedEnvelope getBounds() {
FeatureIterator<F> fi = null;
ReferencedEnvelope bounds = null;
try {
fi = features();
while (fi.hasNext()) {
Feature f = fi.next();
ReferencedEnvelope re = ReferencedEnvelope.reference(f.getBounds());
if (bounds == null) {
bounds = re;
} else {
bounds.expandToInclude(re);
}
}
} finally {
if (fi != null) {
fi.close();
}
}
return bounds;
}
}