com.dimajix.shaded.everit.schema.loader.JsonPointerEvaluator Maven / Gradle / Ivy
package com.dimajix.shaded.everit.schema.loader;
import static java.util.Arrays.asList;
import static java.util.Collections.emptyList;
import static java.util.Objects.requireNonNull;
import static com.dimajix.shaded.everit.schema.loader.OrgJsonUtil.toMap;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UncheckedIOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.util.LinkedList;
import java.util.function.Supplier;
import com.dimajix.shaded.everit.schema.JSONPointerException;
import com.dimajix.shaded.everit.schema.SchemaException;
import com.dimajix.shaded.everit.schema.SchemaLocation;
import com.dimajix.shaded.json.JSONException;
import com.dimajix.shaded.json.JSONObject;
import com.dimajix.shaded.json.JSONTokener;
/**
* @author erosb
*/
class JsonPointerEvaluator {
/**
* Data-transfer object for holding the result of a JSON pointer query.
*/
static class QueryResult {
private final JsonObject containingDocument;
private final JsonValue queryResult;
/**
* Constructor.
*
* @param containingDocument
* the JSON document which contains the query result.
* @param queryResult
* the JSON object being the result of the query execution.
*/
QueryResult(JsonObject containingDocument, JsonValue queryResult) {
this.containingDocument = requireNonNull(containingDocument, "containingDocument cannot be null");
this.queryResult = requireNonNull(queryResult, "queryResult cannot be null");
}
/**
* Getter for {@link #containingDocument}.
*
* @return the JSON document which contains the query result.
*/
public JsonObject getContainingDocument() {
return containingDocument;
}
/**
* Getter for {@link #queryResult}.
*
* @return the JSON object being the result of the query execution.
*/
public JsonValue getQueryResult() {
return queryResult;
}
}
private static JsonObject executeWith(final SchemaClient client, final String url) {
String resp = null;
BufferedReader buffReader = null;
InputStreamReader reader = null;
try {
InputStream responseStream = client.get(url);
reader = new InputStreamReader(responseStream, Charset.defaultCharset());
buffReader = new BufferedReader(reader);
String line;
StringBuilder strBuilder = new StringBuilder();
while ((line = buffReader.readLine()) != null) {
strBuilder.append(line);
}
resp = strBuilder.toString();
return new JsonObject(toMap(new JSONObject(new JSONTokener(resp))));
} catch (IOException e) {
throw new UncheckedIOException(e);
} catch (JSONException e) {
throw new SchemaException("failed to parse " + resp, e);
} finally {
try {
if (buffReader != null) {
buffReader.close();
}
if (reader != null) {
reader.close();
}
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
}
static final JsonPointerEvaluator forDocument(JsonObject document, String fragment) {
return new JsonPointerEvaluator(() -> document, fragment);
}
private static JsonObject configureBasedOnState(JsonObject obj, LoadingState callingState, String id) {
URI documentURI = validateURI(callingState, id).asJavaURI();
obj.ls = callingState.createCopyForNewSchemaJson(documentURI, obj, new SchemaLocation(documentURI, emptyList()));
return obj;
}
static final JsonPointerEvaluator forURL(SchemaClient schemaClient, String url, LoadingState callingState) {
Uri uri = validateURI(callingState, url);
return new JsonPointerEvaluator(
() -> configureBasedOnState(executeWith(schemaClient, uri.toBeQueried.toString()), callingState,
uri.toBeQueried.toString()),
uri.fragment);
}
private static Uri validateURI(LoadingState callingState, String toBeQueried) {
try {
return Uri.parse(toBeQueried);
} catch (URISyntaxException e) {
throw callingState.createSchemaException(e);
}
}
private final Supplier documentProvider;
private final String fragment;
JsonPointerEvaluator(Supplier documentProvider, String fragment) {
this.documentProvider = documentProvider;
this.fragment = fragment;
}
/**
* Queries from {@code document} based on this pointer.
*
* @return a DTO containing the query result and the root document containing the query result.
* @throws IllegalArgumentException
* if the pointer does not start with {@code '#'}.
*/
public QueryResult query() {
JsonObject document = documentProvider.get();
if (fragment.isEmpty()) {
return new QueryResult(document, document);
}
JsonObject foundById = ReferenceLookup.lookupObjById(document, fragment);
if (foundById != null) {
return new QueryResult(document, foundById);
}
String[] path = fragment.split("/");
if ((path[0] == null) || !path[0].startsWith("#")) {
throw new IllegalArgumentException("JSON pointers must start with a '#'");
}
try {
JsonValue result;
LinkedList tokens = new LinkedList<>(asList(path));
tokens.poll();
if (tokens.isEmpty()) {
result = document;
} else {
result = queryFrom(document, tokens);
}
return new QueryResult(document, result);
} catch (JSONPointerException e) {
throw new SchemaException(e.getMessage());
}
}
private String unescape(String token) {
try {
return URLDecoder.decode(token, "utf-8").replace("~1", "/").replace("~0", "~").replace("\\\"", "\"").replace("\\\\", "\\");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
private JsonValue queryFrom(JsonValue document, LinkedList tokens) {
String key = unescape(tokens.poll());
JsonValue next = document.canBeMappedTo(JsonObject.class, obj -> obj.childFor(key))
.orMappedTo(JsonArray.class, arr -> arr.at(Integer.parseInt(key)))
.requireAny();
if (tokens.isEmpty()) {
return next;
}
return queryFrom(next, tokens);
}
}
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