/*
* 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.jclouds.http.functions;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicReference;
import javax.annotation.Resource;
import org.jclouds.http.HttpResponse;
import org.jclouds.json.internal.GsonWrapper;
import org.jclouds.logging.Logger;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.io.Closeables;
import com.google.common.util.concurrent.Atomics;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.inject.TypeLiteral;
/**
* @author Adrian Cole
*/
public class ParseFirstJsonValueNamed<T> implements Function<HttpResponse, T> {
@Resource
protected Logger logger = Logger.NULL;
private final GsonWrapper json;
private final TypeLiteral<T> type;
private final ImmutableSet<String> nameChoices;
/**
* @param nameChoices
* tried in order, first match wins
*/
public ParseFirstJsonValueNamed(GsonWrapper json, TypeLiteral<T> type, String... nameChoices) {
this.json = checkNotNull(json, "json");
this.type = checkNotNull(type, "type");
this.nameChoices = ImmutableSet.copyOf(checkNotNull(nameChoices, "nameChoices"));
}
@Override
public T apply(HttpResponse arg0) {
if (arg0.getPayload() == null)
return nothing();
JsonReader reader = null;
try {
reader = new JsonReader(new InputStreamReader(arg0.getPayload().getInput()));
// in case keys are not in quotes
reader.setLenient(true);
AtomicReference<String> name = Atomics.newReference();
JsonToken token = reader.peek();
for (; token != JsonToken.END_DOCUMENT && nnn(reader, token, name); token = skipAndPeek(token, reader)) {
}
if (name.get() == null) {
logger.trace("did not object named %s in json from response %s", nameChoices, arg0);
return nothing();
} else if (nameChoices.contains(name.get())) {
return json.delegate().<T> fromJson(reader, type.getType());
} else {
return nothing();
}
} catch (IOException e) {
throw new RuntimeException(String.format(
"error reading from stream, parsing object named %s from http response %s", nameChoices, arg0), e);
} finally {
Closeables.closeQuietly(reader);
arg0.getPayload().release();
}
}
@SuppressWarnings("unchecked")
private T nothing() {
if (type.getRawType().isAssignableFrom(Set.class))
return (T) ImmutableSet.of();
else if (type.getRawType().isAssignableFrom(List.class))
return (T) ImmutableList.of();
else if (type.getRawType().isAssignableFrom(Map.class))
return (T) ImmutableMap.of();
return null;
}
private boolean nnn(JsonReader reader, JsonToken token, AtomicReference<String> name) throws IOException {
if (token == JsonToken.NAME) {
String name2 = reader.nextName();
if (nameChoices.contains(name2)) {
name.set(name2);
return false;
}
}
return true;
}
private JsonToken skipAndPeek(JsonToken token, JsonReader reader) throws IOException {
switch (token) {
case BEGIN_ARRAY:
reader.beginArray();
break;
case END_ARRAY:
reader.endArray();
break;
case BEGIN_OBJECT:
reader.beginObject();
break;
case END_OBJECT:
reader.endObject();
break;
case NAME:
// NOTE that we have already advanced on NAME in the eval block;
break;
case STRING:
reader.nextString();
break;
case NUMBER:
reader.nextString();
break;
case BOOLEAN:
reader.nextBoolean();
break;
case NULL:
reader.nextNull();
break;
case END_DOCUMENT:
break;
}
return reader.peek();
}
}