/*
* Copyright 2013 Esri.
*
* Licensed 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 com.esri.gpt.control.webharvest.client.dcat;
import com.esri.gpt.catalog.harvest.protocols.HarvestProtocolDCAT;
import com.esri.gpt.framework.dcat.DcatParserAdaptor;
import com.esri.gpt.framework.dcat.dcat.DcatDistribution;
import com.esri.gpt.framework.dcat.dcat.DcatDistributionList;
import com.esri.gpt.framework.dcat.dcat.DcatRecord;
import com.esri.gpt.framework.resource.api.Publishable;
import com.esri.gpt.framework.util.ReadOnlyIterator;
import com.esri.gpt.framework.util.Val;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.regex.Pattern;
/**
* DCAT adaptor.
*/
class DCATIteratorAdaptor implements Iterable<Publishable> {
private DcatParserAdaptor adaptor;
private Pattern formatPattern;
/**
* Creates instance of the adaptor.
* <p>
* Format property is a value of the 'format' attribute within 'Distribution'
* array in the DCAT JSON response.
* </p>
* @param format format;
* @param adaptor parser adaptor
*/
public DCATIteratorAdaptor(String format, DcatParserAdaptor adaptor) {
this.adaptor = adaptor;
try {
formatPattern = Pattern.compile(format, Pattern.CASE_INSENSITIVE);
} catch (Exception ex) {
formatPattern = Pattern.compile(HarvestProtocolDCAT.FORMAT_PATTERN_DEFAULT_VALUE, Pattern.CASE_INSENSITIVE);
}
}
/**
* Closes adaptor.
* <p>
* It will also close underlying parser adaptor through the call to {@link DcatParserAdaptor#close}.
* </p>
*/
public void close() {
if (adaptor!=null) {
adaptor.close();
adaptor = null;
}
}
@Override
public Iterator<Publishable> iterator() {
return new DCATIterator(formatPattern);
}
/**
* DCAT iterator.
*/
private class DCATIterator extends ReadOnlyIterator<Publishable> {
private Pattern formatPattern;
private Iterator<DcatRecord> iterator = adaptor!=null? adaptor.iterator(): null;
private DcatRecord record;
/**
* Creates instance of the iterator.
* @param formatPattern format pattern to select access URL
*/
public DCATIterator(Pattern formatPattern) {
this.formatPattern = formatPattern;
}
@Override
public boolean hasNext() {
// no iterator? end of story
if (iterator==null) {
return false;
}
// cached accessUrl non empty? next() hasn't been called yet
if (record!=null) {
return true;
}
// anything more in the iterator?
if (!iterator.hasNext()) {
return false;
}
// find something with access URL present
while(iterator.hasNext()) {
record = iterator.next();
if (record!=null) {
return true;
}
}
return false;
}
@Override
public Publishable next() {
if (record==null) {
throw new NoSuchElementException();
}
DCATRecord dcatRecord = new DCATRecord(record);
record = null;
return dcatRecord;
}
/**
* Selects access URL.
* @param r DCAT record
* @return access URL or empty string if no access URL present
*/
private String selectAccessUrl(DcatRecord r) {
DcatDistributionList distList = r.getDistribution();
for (DcatDistribution d : distList) {
if (!d.getAccessURL().isEmpty() && formatPattern.matcher(Val.chkStr(d.getMediaType(), d.getFormat())).matches()) {
return d.getAccessURL();
}
}
return "";
}
}
}