org.geotools.feature.collection.AbstractFeatureCollection Maven / Gradle / Ivy
/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2003-2012, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.feature.collection;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
import org.geotools.data.DataUtilities;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.feature.FeatureIterator;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.filter.Filter;
import org.opengis.filter.sort.SortBy;
/**
* Implement a feature collection just based on provision of an {@link Iterator}.
*
* This implementation asks you to implement:
*
*
* - {@link #openIterator()}
*
- {@link #size()}
*
- User interaction is provided by the public API for FeatureCollection:
*
* - {@link #features()}: makes use of {@link DelegateSimpleFeatureIterator} (if needed)
* to wrap your iterator up as a SimpleFeatureIterator for public use.
*
* This is the origional implementation of FeatureCollection and is recommended when
* presenting {@link Collection} classes as a FeatureCollection.
*
* @author Jody Garnett (LISAsoft)
*/
public abstract class AbstractFeatureCollection implements SimpleFeatureCollection {
/** id used when serialized to gml */
protected String id;
protected SimpleFeatureType schema;
protected AbstractFeatureCollection(SimpleFeatureType memberType) {
this.id = id == null ? "featureCollection" : id;
this.schema = memberType;
}
//
// SimpleFeatureCollection - Feature Access
//
public SimpleFeatureIterator features() {
Iterator iterator = openIterator();
if (iterator instanceof SimpleFeatureIterator) {
return (SimpleFeatureIterator) iterator;
} else {
SimpleFeatureIterator iter = new DelegateSimpleFeatureIterator(iterator);
return iter;
}
}
/**
* Factory method used to open an iterator over collection contents for use by {@link
* #iterator()} and {@link #features()}.
*
* If you return an instance of FeatureIterator some effort is taken to call the {@link
* FeatureIterator#close()} internally, however we cannot offer any assurance that client code
* using {@link #iterator()} will perform the same check.
*
* @return Iterator over collection contents
*/
protected abstract Iterator openIterator();
/**
* Returns the number of elements in this collection.
*
* @return Number of items, or Interger.MAX_VALUE
*/
public abstract int size();
/**
* Returns true if this collection contains the specified element. .
*
* 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 true if this collection contains the specified element.
*/
public boolean contains(Object o) {
Iterator e = null;
e = iterator();
try {
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 {
if (e instanceof FeatureIterator) {
((FeatureIterator) e).close();
}
}
}
/**
* Returns true if this collection contains all of the elements in the specified
* collection.
*
*
*
* @param c collection to be checked for containment in this collection.
* @return true 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();
while (e.hasNext()) {
if (!contains(e.next())) {
return false;
}
}
return true;
}
//
// Contents
//
//
/**
* Provides acess to {@link #openIterator()} used to traverse collection contents.
*
*
You are asked to perform the following check when finished with the iterator:
*
*
if( e instanceof FeatureIterator ){
* (FeatureIterator)iterator).close();
* }
*
* @return Iterator traversing collection contents
*/
public final Iterator iterator() {
Iterator iterator = openIterator();
return iterator;
}
/** @return true if this collection contains no elements. */
public boolean isEmpty() {
Iterator iterator = iterator();
try {
return !iterator.hasNext();
} finally {
if (iterator instanceof FeatureIterator) {
((FeatureIterator) iterator).close();
}
}
}
/**
* 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 e = null;
try {
e = iterator();
for (int i = 0; e.hasNext(); i++) result[i] = e.next();
return result;
} finally {
if (e instanceof FeatureIterator) {
((FeatureIterator) e).close();
}
}
}
@SuppressWarnings("unchecked")
public O[] toArray(O[] a) {
int size = size();
if (a.length < size) {
a = (O[]) java.lang.reflect.Array.newInstance(a.getClass().getComponentType(), size);
}
Iterator 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 {
if (it instanceof FeatureIterator) {
((FeatureIterator) it).close();
}
}
}
public void accepts(
org.opengis.feature.FeatureVisitor visitor, org.opengis.util.ProgressListener progress)
throws IOException {
DataUtilities.visit(this, visitor, progress);
}
//
// Feature Collections API
//
public SimpleFeatureCollection subCollection(Filter filter) {
if (filter == Filter.INCLUDE) {
return this;
}
return new SubFeatureCollection(this, filter);
}
public SimpleFeatureCollection sort(SortBy order) {
return new SubFeatureList(this, order);
}
public String getID() {
return id;
}
public SimpleFeatureType getSchema() {
return schema;
}
/** Subclasses need to override this. */
public abstract ReferencedEnvelope getBounds();
}