/**
* 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.ambari.server.api.services.serializers;
import org.apache.ambari.server.api.services.ResultStatus;
import org.apache.ambari.server.api.services.Result;
import org.apache.ambari.server.api.util.TreeNodeImpl;
import org.apache.ambari.server.controller.spi.Resource;
import org.apache.ambari.server.api.util.TreeNode;
import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.util.DefaultPrettyPrinter;
import java.io.*;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;
/**
* JSON serializer.
* Responsible for representing a result as JSON.
*/
public class JsonSerializer implements ResultSerializer {
/**
* Factory used to create JSON generator.
*/
JsonFactory m_factory = new JsonFactory();
ObjectMapper m_mapper = new ObjectMapper(m_factory);
/**
* Generator which writes JSON.
*/
JsonGenerator m_generator;
@Override
public Object serialize(Result result) {
try {
ByteArrayOutputStream bytesOut = init();
if (result.getStatus().isErrorState()) {
return serializeError(result.getStatus());
}
processNode(result.getResultTree());
m_generator.close();
return bytesOut.toString("UTF-8");
} catch (IOException e) {
//todo: exception handling. Create ResultStatus 500 and call serializeError
throw new RuntimeException("Unable to serialize to json: " + e, e);
}
}
@Override
public Object serializeError(ResultStatus error) {
try {
ByteArrayOutputStream bytesOut = init();
//m_mapper.writeValue(m_generator, error);
m_generator.writeStartObject();
m_generator.writeNumberField("status", error.getStatus().getStatus());
m_generator.writeStringField("message", error.getMessage());
m_generator.writeEndObject();
m_generator.close();
return bytesOut.toString("UTF-8");
} catch (IOException e) {
//todo: exception handling
throw new RuntimeException("Unable to serialize to json: " + e, e);
}
}
private ByteArrayOutputStream init() throws IOException {
ByteArrayOutputStream bytesOut = new ByteArrayOutputStream();
m_generator = createJsonGenerator(bytesOut);
DefaultPrettyPrinter p = new DefaultPrettyPrinter();
p.indentArraysWith(new DefaultPrettyPrinter.Lf2SpacesIndenter());
m_generator.setPrettyPrinter(p);
return bytesOut;
}
private void processNode(TreeNode<Resource> node) throws IOException {
String name = node.getName();
Resource r = node.getObject();
if (r == null) {
if (name != null) {
if (node.getParent() == null) {
m_generator.writeStartObject();
writeHref(node);
}
m_generator.writeArrayFieldStart(name);
}
} else {
m_generator.writeStartObject();
writeHref(node);
// resource props
handleResourceProperties(getTreeProperties(r.getPropertiesMap()));
}
for (TreeNode<Resource> child : node.getChildren()) {
processNode(child);
}
if (r == null) {
if (name != null) {
m_generator.writeEndArray();
if (node.getParent() == null) {
m_generator.writeEndObject();
}
}
} else {
m_generator.writeEndObject();
}
}
private TreeNode<Map<String, Object>> getTreeProperties (Map<String, Map<String, Object>> propertiesMap) {
TreeNode<Map<String, Object>> treeProperties =
new TreeNodeImpl<Map<String, Object>>(null, new HashMap<String, Object>(), null);
for (Map.Entry<String, Map<String, Object>> entry : propertiesMap.entrySet()) {
String category = entry.getKey();
TreeNode<Map<String, Object>> node;
if (category == null) {
node = treeProperties;
} else {
node = treeProperties.getChild(category);
if (node == null) {
String[] tokens = category.split("/");
node = treeProperties;
for (String t : tokens) {
TreeNode<Map<String, Object>> child = node.getChild(t);
if (child == null) {
child = node.addChild(new HashMap<String, Object>(), t);
}
node = child;
}
}
}
Map<String, Object> properties = entry.getValue();
for (Map.Entry<String, Object> propertyEntry : properties.entrySet()) {
node.getObject().put(propertyEntry.getKey(), propertyEntry.getValue());
}
}
return treeProperties;
}
private void handleResourceProperties(TreeNode<Map<String, Object>> node) throws IOException {
String category = node.getName();
if (category != null) {
m_generator.writeFieldName(category);
m_generator.writeStartObject();
}
for (Map.Entry<String, Object> entry : node.getObject().entrySet()) {
m_generator.writeFieldName(entry.getKey());
m_mapper.writeValue(m_generator, entry.getValue());
}
for (TreeNode<Map<String, Object>> n : node.getChildren()) {
handleResourceProperties(n);
}
if (category != null) {
m_generator.writeEndObject();
}
}
private JsonGenerator createJsonGenerator(ByteArrayOutputStream baos) throws IOException {
JsonGenerator generator = m_factory.createJsonGenerator(new OutputStreamWriter(baos,
Charset.forName("UTF-8").newEncoder()));
DefaultPrettyPrinter p = new DefaultPrettyPrinter();
p.indentArraysWith(new DefaultPrettyPrinter.Lf2SpacesIndenter());
generator.setPrettyPrinter(p);
return generator;
}
private void writeHref(TreeNode<Resource> node) throws IOException {
String hrefProp = node.getProperty("href");
if (hrefProp != null) {
m_generator.writeStringField("href", hrefProp);
}
}
}