io.permazen.core.EnumValue Maven / Gradle / Ivy
/*
* Copyright (C) 2015 Archie L. Cobbs. All rights reserved.
*/
package io.permazen.core;
import com.google.common.base.Preconditions;
import java.io.Serializable;
/**
* Holds a non-null {@link Enum} value without actually referencing any Java {@link Enum} type.
* Instead, instances hold a name and ordinal value.
*
*
* Instances are immutable.
*
* @see io.permazen.core.type.EnumFieldType
* @see io.permazen.EnumConverter
*/
public class EnumValue implements Serializable {
private static final long serialVersionUID = 7325751293674981562L;
private final String name;
private final int ordinal;
/**
* Constructor taking name and ordinal value.
*
* @param name enum name
* @param ordinal enum ordinal value
* @throws IllegalArgumentException if {@code ordinal} is negative
* @throws IllegalArgumentException if {@code name} is null
*/
public EnumValue(String name, int ordinal) {
Preconditions.checkArgument(name != null, "null name");
Preconditions.checkArgument(ordinal >= 0, "invalid negative ordinal");
this.name = name;
this.ordinal = ordinal;
}
/**
* Constructor taking an {@link Enum} value.
*
* @param value enum value
* @throws IllegalArgumentException if {@code value} is null
*/
public EnumValue(Enum value) {
Preconditions.checkArgument(value != null, "null value");
this.name = value.name();
this.ordinal = value.ordinal();
}
/**
* Get the enum name.
*
* @return enum value name
*/
public String getName() {
return this.name;
}
/**
* Get the enum ordinal value.
*
* @return enum value ordinal
*/
public int getOrdinal() {
return this.ordinal;
}
/**
* Find the instance in the given {@link Enum} type that matches this instance in both name and ordinal value, if any.
*
*
* Note: to match only by name, just use {@link Enum#valueOf Enum.valueOf()}.
*
* @param type {@link Enum} type
* @param enum type
* @return matching instance of type {@code type}, or null if none exists
* @throws IllegalArgumentException if {@code type} is null
*/
public > T find(Class type) {
Preconditions.checkArgument(type != null, "null type");
final T value;
try {
value = Enum.valueOf(type, this.name);
} catch (IllegalArgumentException e) {
return null;
}
return value.ordinal() == this.ordinal ? value : null;
}
// Object
@Override
public String toString() {
return this.name + "#" + this.ordinal;
}
@Override
public int hashCode() {
return this.name.hashCode() ^ this.ordinal;
}
@Override
public boolean equals(Object obj) {
if (obj == this)
return true;
if (obj == null || obj.getClass() != this.getClass())
return false;
final EnumValue that = (EnumValue)obj;
return this.name.equals(that.name) && this.ordinal == that.ordinal;
}
}