org.opendaylight.yangtools.yang.common.DerivedString Maven / Gradle / Ivy
/*
* Copyright (c) 2018 Pantheon Technologies, s.r.o. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.yang.common;
import com.google.common.annotations.Beta;
import java.io.Serial;
import org.eclipse.jdt.annotation.NonNullByDefault;
import org.eclipse.jdt.annotation.Nullable;
/**
* Abstract base class for objects which are string-equivalent to canonical string representation specified
* in a YANG model. Note that each subclass of {@link DerivedString} defines its own {@link #hashCode()} and
* {@link #equals(Object)} contracts based on implementation particulars.
*
*
* Given the following YANG snippet:
*
* typedef foo {
* type string;
* pattern "[1-9]?[0-9]";
* }
*
* typedef bar {
* type foo;
* patter "[1-9][0-9]";
* }
*
* typedef baz {
* type foo;
* }
*
* it is obvious we could use a storage class with 'int' as the internal representation of all three types and define
* operations on top of it. In this case we would define:
*
* - {@code public class FooDerivedString extends DerivedString
}, which implements all abstract
* methods of {@link DerivedString} as final methods. It will notably not override {@link #validator()} and
* must not be final.
* - {@code public final class FooDerivedStringSupport extends DerivedStringSupport
}, which
* forms the baseline validator and instantiation for {@code FooDerivedString}. It should be a singleton class
* with a getInstance() method.
* - {@code public class BarDerivedString extends FooDerivedString}, which overrides {@link #validator()} to
* indicate its contents have been validated to conform to bar -- it does that by returning the singleton
* instance of {@code BarDerivedStringValidator}.
* - {@code public final class BarDerivedStringValidator extends DerivedStringValidator
*
* Since {@code baz} is not defining any new restrictions, all instances of FooDerivedString are valid for it and we
* do not have to define any additional support.
*
*
* It is important for {@link DerivedString} subclasses not to be final because any YANG type can be further extended
* and adding a final class in that hierarchy would prevent a proper class from being defined.
*
* @param derived string representation
* @author Robert Varga
*/
@Beta
@NonNullByDefault
public abstract class DerivedString> implements CanonicalValue {
@Serial
private static final long serialVersionUID = 1L;
@Override
public abstract int hashCode();
@Override
public abstract boolean equals(@Nullable Object obj);
@Override
public final String toString() {
return toCanonicalString();
}
}