/*
* Copyright 2012 Guido Steinacker
*
* 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 de.otto.jsonhome.parser;
import de.otto.jsonhome.model.*;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import static de.otto.jsonhome.model.Authentication.authReq;
import static de.otto.jsonhome.model.DirectLink.directLink;
import static de.otto.jsonhome.model.Documentation.documentation;
import static de.otto.jsonhome.model.HintsBuilder.hintsBuilder;
import static de.otto.jsonhome.model.HrefVar.hrefVar;
import static de.otto.jsonhome.model.JsonHomeBuilder.jsonHomeBuilder;
import static de.otto.jsonhome.model.Precondition.preconditionOf;
import static de.otto.jsonhome.model.TemplatedLink.templatedLink;
/**
* A JsonHomeParser that is implemented using Jackson.
*
* @author Guido Steinacker
* @since 26.10.12
*/
public class JacksonJsonHomeParser implements JsonHomeParser {
private static final Logger LOG = LoggerFactory.getLogger(JacksonJsonHomeParser.class);
public static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
@Override
public JsonHome parse(final InputStream stream) {
try {
final JsonNode jsonNode = OBJECT_MAPPER.readTree(stream);
if (jsonNode != null && jsonNode.has("resources")) {
final JsonHomeBuilder builder = jsonHomeBuilder();
final JsonNode resourcesNode = jsonNode.get("resources");
final Iterator<String> fieldNames = resourcesNode.getFieldNames();
while (fieldNames.hasNext()) {
final String fieldName = fieldNames.next();
final JsonNode resourceNode = resourcesNode.get(fieldName);
builder.addResource(resourceLinkFrom(URI.create(fieldName), resourceNode));
}
return builder.build();
}
} catch (final JsonProcessingException e) {
LOG.error("Unable to parse json-home document: {}", e.getMessage());
throw new IllegalArgumentException("Error parsing json-home document: " + e.getMessage(), e);
} catch (final IOException e) {
LOG.error("Unable to get json-home from stream: {}", e.getMessage());
// TODO: define more specific exceptions
throw new IllegalStateException("Unable to get json-home document from stream: " + e.getMessage(), e);
}
throw new IllegalArgumentException("Unable to parse json-home document: no resources defined.");
}
private ResourceLink resourceLinkFrom(final URI relationTypeUri, final JsonNode resourceLinkNode) {
if (resourceLinkNode.has("href")) {
return directLink(
relationTypeUri,
URI.create(resourceLinkNode.get("href").getTextValue()),
hintsFrom(resourceLinkNode.get("hints"))
);
} else {
return templatedLink(
relationTypeUri,
resourceLinkNode.get("href-template").getTextValue(),
hrefVarsFrom(resourceLinkNode.get("href-vars")),
hintsFrom(resourceLinkNode.get("hints"))
);
}
}
private List<HrefVar> hrefVarsFrom(final JsonNode jsonNode) {
if (jsonNode.isContainerNode()) {
final List<HrefVar> hrefVars = new ArrayList<HrefVar>();
final Iterator<String> varNames = jsonNode.getFieldNames();
while (varNames.hasNext()) {
final String varName = varNames.next();
final JsonNode varRefNode = jsonNode.get(varName);
hrefVars.add(hrefVar(varName, URI.create(varRefNode.getTextValue())));
}
return hrefVars;
} else {
throw new IllegalStateException("Unable to construct a TemplatedLink without href-vars.");
}
}
private Hints hintsFrom(final JsonNode hints) {
final HintsBuilder builder = hintsBuilder();
if (hints != null) {
if (hints.has("allow")) {
final Iterator<JsonNode> iterator = hints.get("allow").getElements();
while (iterator.hasNext()) {
builder.allowing(Allow.valueOf(iterator.next().getTextValue()));
}
}
if (hints.has("representations")) {
final Iterator<JsonNode> iterator = hints.get("representations").getElements();
while (iterator.hasNext()) {
builder.representedAs(iterator.next().getTextValue());
}
}
if (hints.has("docs") || hints.has("description") || hints.has("detailedDescription")) {
final URI docUri = hints.has("docs") ? URI.create(hints.get("docs").getTextValue()) : null;
final List<String> description = new ArrayList<String>();
final Iterator<JsonNode> elements = hints.has("description")
? hints.get("description").getElements()
: Collections.<JsonNode>emptyList().iterator();
while (elements.hasNext()) {
description.add(elements.next().getTextValue());
}
final String detailedDescription = hints.has("detailedDescription") ? hints.get("detailedDescription").getTextValue() : null;
builder.with(documentation(description, detailedDescription, docUri));
}
if (hints.has("accept-ranges")) {
final Iterator<JsonNode> iterator = hints.get("accept-ranges").getElements();
while (iterator.hasNext()) {
final String textValue = iterator.next().getTextValue();
if (!textValue.isEmpty()) {
builder.acceptingRanges(textValue);
}
}
}
if (hints.has("prefer")) {
final Iterator<JsonNode> iterator = hints.get("prefer").getElements();
while (iterator.hasNext()) {
final String textValue = iterator.next().getTextValue();
if (!textValue.isEmpty()) {
builder.preferring(textValue);
}
}
}
if (hints.has("precondition-req")) {
final Iterator<JsonNode> iterator = hints.get("precondition-req").getElements();
while (iterator.hasNext()) {
final String textValue = iterator.next().getTextValue();
if (!textValue.isEmpty()) {
builder.requiring(preconditionOf(textValue));
}
}
}
if (hints.has("auth-req")) {
final List<Authentication> authentications = new ArrayList<Authentication>();
final Iterator<JsonNode> iterator = hints.get("auth-req").getElements();
while (iterator.hasNext()) {
final JsonNode authNode = iterator.next();
final String scheme = authNode.get("scheme").getTextValue();
final List<String> realms = new ArrayList<String>();
if (authNode.has("realms")) {
final Iterator<JsonNode> realmIter = authNode.get("realms").getElements();
while (realmIter.hasNext()) {
realms.add(realmIter.next().getTextValue());
}
}
authentications.add(authReq(scheme, realms));
}
builder.withAuthRequired(authentications);
}
if (hints.has("accept-put")) {
final Iterator<JsonNode> iterator = hints.get("accept-put").getElements();
while (iterator.hasNext()) {
builder.acceptingForPut(iterator.next().getTextValue());
}
}
if (hints.has("accept-post")) {
final Iterator<JsonNode> iterator = hints.get("accept-post").getElements();
while (iterator.hasNext()) {
builder.acceptingForPost(iterator.next().getTextValue());
}
}
if (hints.has("status")) {
builder.withStatus(Status.valueOf(hints.get("status").getTextValue().toUpperCase()));
}
}
return builder.build();
}
}