org.jaudiolibs.audioservers.util.ObjectLookup Maven / Gradle / Ivy
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2020 Neil C Smith.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice shall be included in
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*
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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package org.jaudiolibs.audioservers.util;
import java.util.ArrayList;
/**
* A utility class that can be used to implement find() and findAll() support for
* extension Objects.
*
*/
public final class ObjectLookup {
public final static ObjectLookup EMPTY = new ObjectLookup(new Object[0]);
private final ObjectLookup parent;
private final Object[] objs;
/**
* Create an ObjectLookup wrapping the provided collection of Objects.
*
* Objects may not be null. The order of Objects is maintained in results.
*
* @param objs
*/
public ObjectLookup(Object ... objs) {
this(null, objs);
}
/**
* Create an ObjectLookup wrapping the provided collection of Objects.
*
* Results will be combined with the results from the optional parent lookup.
* Object within this lookup will be returned first.
*
* Objects may not be null. The order of Objects is maintained in results.
*
* @param parent
* @param objs
*/
public ObjectLookup(ObjectLookup parent, Object ... objs) {
for (Object o : objs) {
if (o == null) {
throw new NullPointerException();
}
}
this.parent = parent;
this.objs = objs.clone();
}
/**
* Find the first Object of the given type, or null.
*
* @param
* @param type
* @return Object of type, or null
*/
public T find(Class type) {
for (Object obj : objs) {
if (type.isInstance(obj)) {
return type.cast(obj);
}
}
return parent == null ? null : parent.find(type);
}
/**
* Find all Objects of the given type.
*
* @param
* @param type
* @return Iterable of the given type, never null
*/
public Iterable findAll(Class type) {
ArrayList list = new ArrayList();
for (Object obj : objs) {
if (type.isInstance(obj)) {
list.add(type.cast(obj));
}
}
if (parent != null) {
for (T obj : parent.findAll(type)) {
list.add(obj);
}
}
return list;
}
}