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* Licensed to the Apache Software Foundation (ASF) under one
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* 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.olingo.odata2.core.ep.producer;
import java.io.IOException;
import java.io.Writer;
import java.util.List;
import java.util.Map;
import org.apache.olingo.odata2.api.commons.InlineCount;
import org.apache.olingo.odata2.api.ep.EntityProviderException;
import org.apache.olingo.odata2.api.ep.EntityProviderWriteProperties;
import org.apache.olingo.odata2.api.ep.callback.TombstoneCallback;
import org.apache.olingo.odata2.api.ep.callback.TombstoneCallbackResult;
import org.apache.olingo.odata2.core.ep.aggregator.EntityInfoAggregator;
import org.apache.olingo.odata2.core.ep.util.FormatJson;
import org.apache.olingo.odata2.core.ep.util.JsonStreamWriter;
/**
* Producer for writing an entity collection (a feed) in JSON.
*
*/
public class JsonFeedEntityProducer {
private final EntityProviderWriteProperties properties;
public JsonFeedEntityProducer(final EntityProviderWriteProperties properties) throws EntityProviderException {
this.properties = properties == null ? EntityProviderWriteProperties.serviceRoot(null).build() : properties;
}
public void append(final Writer writer, final EntityInfoAggregator entityInfo, final List<Map<String, Object>> data,
final boolean isRootElement) throws EntityProviderException {
JsonStreamWriter jsonStreamWriter = new JsonStreamWriter(writer);
TombstoneCallback callback = getTombstoneCallback();
try {
jsonStreamWriter.beginObject();
if (isRootElement) {
jsonStreamWriter.name(FormatJson.D)
.beginObject();
}
if (properties.getInlineCountType() == InlineCount.ALLPAGES) {
final int inlineCount = properties.getInlineCount() == null ? 0 : properties.getInlineCount();
jsonStreamWriter.namedStringValueRaw(FormatJson.COUNT, String.valueOf(inlineCount)).separator();
}
jsonStreamWriter.name(FormatJson.RESULTS)
.beginArray();
JsonEntryEntityProducer entryProducer = new JsonEntryEntityProducer(properties);
boolean first = true;
for (final Map<String, Object> entryData : data) {
if (first) {
first = false;
} else {
jsonStreamWriter.separator();
}
entryProducer.append(writer, entityInfo, entryData, false);
}
if (callback != null) {
JsonDeletedEntryEntityProducer deletedEntryProducer = new JsonDeletedEntryEntityProducer(properties);
TombstoneCallbackResult callbackResult = callback.getTombstoneCallbackResult();
List<Map<String, Object>> deletedEntries = callbackResult.getDeletedEntriesData();
if (deletedEntries != null) {
deletedEntryProducer.append(writer, entityInfo, deletedEntries);
}
}
jsonStreamWriter.endArray();
appendNextLink(jsonStreamWriter);
appendDeltaLink(callback, jsonStreamWriter);
if (isRootElement) {
jsonStreamWriter.endObject();
}
jsonStreamWriter.endObject();
} catch (final IOException e) {
throw new EntityProviderException(EntityProviderException.EXCEPTION_OCCURRED.addContent(e.getClass()
.getSimpleName()), e);
}
}
private TombstoneCallback getTombstoneCallback() {
if (properties.getCallbacks() != null
&& properties.getCallbacks().containsKey(TombstoneCallback.CALLBACK_KEY_TOMBSTONE)) {
TombstoneCallback callback =
(TombstoneCallback) properties.getCallbacks().get(TombstoneCallback.CALLBACK_KEY_TOMBSTONE);
return callback;
} else {
return null;
}
}
private void appendNextLink(final JsonStreamWriter jsonStreamWriter) throws IOException {
// Write "next" link.
// To be compatible with other implementations out there, the link is
// written directly after "__next" and not as "{"uri":"next link"}",
// deviating from the OData 2.0 specification.
if (properties.getNextLink() != null) {
jsonStreamWriter.separator()
.namedStringValue(FormatJson.NEXT, properties.getNextLink());
}
}
private void appendDeltaLink(final TombstoneCallback callback, final JsonStreamWriter jsonStreamWriter)
throws IOException {
if (callback != null) {
TombstoneCallbackResult callbackResult = callback.getTombstoneCallbackResult();
String deltaLink = callbackResult.getDeltaLink();
if (deltaLink != null) {
jsonStreamWriter.separator().namedStringValue(FormatJson.DELTA, deltaLink);
}
}
}
}