com.redhat.lightblue.query.RValueExpression Maven / Gradle / Ivy
/*
Copyright 2013 Red Hat, Inc. and/or its affiliates.
This file is part of lightblue.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see
* rvalue_expression := value | { $valueof : path } | {...} | [...]
*/
public class RValueExpression extends JsonObject {
private static final long serialVersionUID = 1L;
public enum RValueType {
_value,
_dereference,
_null
}
private final Value value;
private final Path path;
private final RValueType type;
public static final RValueExpression NULL = new RValueExpression(null, null, RValueType._null);
/**
* Creates an rvalue expression that is a constant value
*/
public RValueExpression(Value value) {
if (value == null || value.getValue() == null) {
this.value = null;
this.path = null;
this.type = RValueType._null;
} else {
this.value = value;
this.path = null;
this.type = RValueType._value;
}
}
/**
* Creates an rvalue expression that references another field
*/
public RValueExpression(Path p) {
this(null, p, RValueType._dereference);
}
public static RValueExpression nullRValue() {
return NULL;
}
private RValueExpression(Value value, Path path, RValueType type) {
this.value = value;
this.path = path;
this.type = type;
}
/**
* The constant value. Null if this rvalue references a field
*/
public Value getValue() {
return value;
}
/**
* The referenced field. Null if this rvalue is a constant
*/
public Path getPath() {
return path;
}
/**
* The reference type.
*/
public RValueType getType() {
return type;
}
@Override
public JsonNode toJson() {
switch (type) {
case _value:
return value.toJson();
case _dereference:
ObjectNode node = getFactory().objectNode();
node.put("$valueof", path.toString());
return node;
default:
return getFactory().nullNode();
}
}
/**
* Parses an rvalue from a json node.
*/
public static RValueExpression fromJson(JsonNode node) {
if (node instanceof ObjectNode) {
if (node.size() == 1) {
JsonNode path = node.get("$valueof");
if (path != null && path.isValueNode()) {
return new RValueExpression(new Path(path.asText()));
} else {
return new RValueExpression(new Value(node));
}
} else {
return new RValueExpression(new Value(node));
}
}
if (node instanceof ArrayNode) {
return new RValueExpression(new Value(node));
} else if (node.isValueNode()) {
if (node.asText().equals("$null")) {
return NULL;
} else {
return new RValueExpression(Value.fromJson(node));
}
}
throw Error.get(QueryConstants.ERR_INVALID_RVALUE_EXPRESSION, node.toString());
}
@Override
public int hashCode() {
int hash = 7;
hash = 79 * hash + Objects.hashCode(this.value);
hash = 79 * hash + Objects.hashCode(this.path);
hash = 79 * hash + Objects.hashCode(this.type);
return hash;
}
@Override
public boolean equals(Object obj) {
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final RValueExpression other = (RValueExpression) obj;
if (!Objects.equals(this.value, other.value)) {
return false;
}
if (!Objects.equals(this.path, other.path)) {
return false;
}
if (this.type != other.type) {
return false;
}
return true;
}
}