org.trimou.jsonp.resolver.JsonValueResolver Maven / Gradle / Ivy
/*
* Copyright 2016 Martin Kouba
*
* 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 org.trimou.jsonp.resolver;
import static org.trimou.engine.priority.Priorities.rightBefore;
import java.util.List;
import java.util.Map;
import javax.json.JsonArray;
import javax.json.JsonNumber;
import javax.json.JsonObject;
import javax.json.JsonString;
import javax.json.JsonValue;
import javax.json.JsonValue.ValueType;
import org.trimou.engine.resolver.IndexResolver;
import org.trimou.engine.resolver.MapResolver;
import org.trimou.engine.resolver.Placeholder;
import org.trimou.engine.resolver.ResolutionContext;
/**
* JSON Processing Object Model API (JSR 353) resolver. Since {@link JsonObject}
* implements {@link Map} and {@link JsonArray} implements {@link List} this
* resolver is only useful if automatic unwrapping is required. Automatic
* unwrapping means resolving {@link JsonString#getString()} for
* {@link JsonString}, {@link JsonNumber#bigDecimalValue()} for
* {@link JsonNumber}, {@link Boolean#TRUE} for {@link JsonValue#TRUE},
* {@link Boolean#FALSE} for {@link JsonValue#FALSE} and
* {@link Placeholder#NULL} for {@link JsonValue#NULL}.
*
* This resolver should always have higher priority than {@link MapResolver} to
* be able to process instances of {@link JsonObject}.
*
* @author Martin Kouba
*/
public class JsonValueResolver extends IndexResolver {
public static final int JSON_VALUE_RESOLVER_PRIORITY = rightBefore(
MapResolver.MAP_RESOLVER_PRIORITY);
/**
* Use this name if you want to unwrap the current context object (note that
* "this" would be normally matched by ThisResolver)
*/
public static final String NAME_UNWRAP_THIS = "unwrapThis";
private final Hint hint;
public JsonValueResolver() {
this(JSON_VALUE_RESOLVER_PRIORITY);
}
/**
* @param priority
*/
public JsonValueResolver(int priority) {
super(priority);
this.hint = new Hint() {
@Override
public Object resolve(Object contextObject, String name,
ResolutionContext context) {
return JsonValueResolver.this.resolve(contextObject, name,
context);
}
};
}
@Override
public Object resolve(Object contextObject, String name,
ResolutionContext context) {
if (contextObject == null || !(contextObject instanceof JsonValue)) {
return null;
}
JsonValue jsonValue = (JsonValue) contextObject;
if (ValueType.ARRAY.equals(jsonValue.getValueType())
&& isAnIndex(name)) {
// Index-based access of JsonArray elements
JsonArray jsonArray = (JsonArray) jsonValue;
// #26 Unwrap the element if necessary
final Integer index = getIndexValue(name, context.getKey(),
jsonArray.size());
if (index != null) {
return unwrapJsonValueIfNecessary(jsonArray.get(index));
}
} else if (ValueType.OBJECT.equals(jsonValue.getValueType())) {
// JsonObject properties
JsonObject jsonObject = (JsonObject) jsonValue;
JsonValue member = jsonObject.get(name);
if (member != null) {
return unwrapJsonValueIfNecessary(member);
}
} else if (name.equals(NAME_UNWRAP_THIS)) {
return unwrapJsonValueIfNecessary(jsonValue);
}
return null;
}
@Override
public Hint createHint(Object contextObject, String name,
ResolutionContext context) {
return hint;
}
private Object unwrapJsonValueIfNecessary(JsonValue jsonValue) {
switch (jsonValue.getValueType()) {
case STRING:
return ((JsonString) jsonValue).getString();
case NUMBER:
return ((JsonNumber) jsonValue).bigDecimalValue();
case TRUE:
return Boolean.TRUE;
case FALSE:
return Boolean.FALSE;
case NULL:
return Placeholder.NULL;
default:
return jsonValue;
}
}
}