org.everit.json.schema.Schema Maven / Gradle / Ivy
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/*
* Copyright (C) 2011 Everit Kft. (http://www.everit.org)
*
* 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.everit.json.schema;
import org.everit.json.schema.internal.JSONPrinter;
import org.json.JSONWriter;
import java.io.StringWriter;
import java.util.Objects;
/**
* Superclass of all other schema validator classes of this package.
*/
public abstract class Schema {
/**
* Abstract builder class for the builder classes of {@code Schema} subclasses. This builder is
* used to load the generic properties of all types of schemas like {@code title} or
* {@code description}.
*
* @param the type of the schema being built by the builder subclass.
*/
public abstract static class Builder {
private String title;
private String description;
private String id;
public Builder title(final String title) {
this.title = title;
return this;
}
public Builder description(final String description) {
this.description = description;
return this;
}
public Builder id(final String id) {
this.id = id;
return this;
}
public abstract S build();
}
private final String title;
private final String description;
private final String id;
/**
* Constructor.
*
* @param builder the builder containing the optional title, description and id attributes of the schema
*/
protected Schema(final Builder builder) {
this.title = builder.title;
this.description = builder.description;
this.id = builder.id;
}
/**
* Performs the schema validation.
*
* @param subject the object to be validated
* @throws ValidationException if the {@code subject} is invalid against this schema.
*/
public abstract void validate(final Object subject);
/**
* Determines if this {@code Schema} instance defines any restrictions for the object property
* denoted by {@code field}. The {@code field} should be a JSON pointer, denoting the property to
* be queried.
*
* For example the field {@code "#/rectangle/a"} is defined by the following schema:
*
*
*
* objectWithSchemaRectangleDep" : {
* "type" : "object",
* "dependencies" : {
* "d" : {
* "type" : "object",
* "properties" : {
* "rectangle" : {"$ref" : "#/definitions/Rectangle" }
* }
* }
* },
* "definitions" : {
* "size" : {
* "type" : "number",
* "minimum" : 0
* },
* "Rectangle" : {
* "type" : "object",
* "properties" : {
* "a" : {"$ref" : "#/definitions/size"},
* "b" : {"$ref" : "#/definitions/size"}
* }
* }
* }
* }
*
*
*
* The default implementation of this method always returns false.
*
* @param field should be a JSON pointer in its string representation.
* @return {@code true} if the propertty denoted by {@code field} is defined by this schema
* instance
*/
public boolean definesProperty(final String field) {
return false;
}
@Override
public boolean equals(final Object o) {
if (this == o) {
return true;
}
if (o instanceof Schema) {
Schema schema = (Schema) o;
return schema.canEqual(this) &&
Objects.equals(title, schema.title) &&
Objects.equals(description, schema.description) &&
Objects.equals(id, schema.id);
} else {
return false;
}
}
@Override
public int hashCode() {
return Objects.hash(title, description, id);
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
public String getId() {
return id;
}
/**
* Describes the instance as a JSONObject to {@code writer}.
*
* First it adds the {@code "title} , {@code "description"} and {@code "id"} properties then calls
* {@link #describePropertiesTo(JSONPrinter)}, which will add the subclass-specific properties.
*
* It is used by {@link #toString()} to serialize the schema instance into its JSON representation.
*
* @param writer it will receive the schema description
*/
public final void describeTo(final JSONPrinter writer) {
writer.object();
writer.ifPresent("title", title);
writer.ifPresent("description", description);
writer.ifPresent("id", id);
describePropertiesTo(writer);
writer.endObject();
}
/**
* Subclasses are supposed to override this method to describe the subclass-specific attributes.
* This method is called by {@link #describeTo(JSONPrinter)} after adding the generic properties if
* they are present ({@code id}, {@code title} and {@code description}). As a side effect,
* overriding subclasses don't have to open and close the object with {@link JSONWriter#object()}
* and {@link JSONWriter#endObject()}.
*
* @param writer it will receive the schema description
*/
void describePropertiesTo(final JSONPrinter writer) {
}
@Override
public String toString() {
StringWriter w = new StringWriter();
describeTo(new JSONPrinter(w));
return w.getBuffer().toString();
}
/**
* Since we add state in subclasses, but want those subclasses to be non final, this allows us to
* have equals methods that satisfy the equals contract.
*
* http://www.artima.com/lejava/articles/equality.html
*/
protected boolean canEqual(final Object other) {
return (other instanceof Schema);
}
}