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/*
* Copyright (c) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package nsk.share.sysdict;
import nsk.share.*;
/**
* A chain of class loaders. Imagine a chain as a tower
* growing downstairs: the 0<sup>th</sup> level is the
* root, and a level n+1 loader has the n<sup>th</sup>
* loader as the parent.
*/
public class ClassLoadersChain {
/**
* Cannot instantiate while a chain root and height
* are not specified.
*
* @see #ClassLoadersChain(ClassLoader,int)
*/
protected ClassLoadersChain() {
}
/**
* Given the <tt>root</tt> loader, instantiate a chain
* of loaders up to the given <tt>height</tt>.
*
* @see #getHeight()
* @see #getRoot()
* @see #getLoader(int)
*/
public ClassLoadersChain(ClassLoader root, int height) {
if (height < 1)
throw new IllegalArgumentException("wrong height: " + height);
loaders = new ClassLoader [ height ];
loaders[0] = root;
for (int i=1; i<height; i++)
loaders[i] = new DummyClassLoader(loaders[i-1]);
}
private ClassLoader loaders[]; // loaders[0] is the root
/**
* Return the loader found at the given <tt>level</tt>.
* The value of <tt>level</tt> must be from <tt>0</tt>
* to <tt>getHeight()-1</tt>.
*
* @see #getHeight()
* @see #getRoot()
*/
public ClassLoader getLoader(int level) {
return loaders[level];
}
/**
* Return the chain's height.
*
* @see #ClassLoadersChain(ClassLoader,int)
* @see #getLoader(int)
*/
public int getHeight() {
return loaders.length;
}
/**
* Return the chain's root loader.
*
* @see #ClassLoadersChain(ClassLoader,int)
* @see #getLoader(int)
*/
public ClassLoader getRoot() {
return loaders[0];
}
}
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