95 lines
2.8 KiB
Java
95 lines
2.8 KiB
Java
/*
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* Copyright (c) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package nsk.share.sysdict;
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import nsk.share.*;
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/**
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* A chain of class loaders. Imagine a chain as a tower
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* growing downstairs: the 0<sup>th</sup> level is the
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* root, and a level n+1 loader has the n<sup>th</sup>
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* loader as the parent.
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*/
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public class ClassLoadersChain {
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/**
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* Cannot instantiate while a chain root and height
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* are not specified.
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*
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* @see #ClassLoadersChain(ClassLoader,int)
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*/
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protected ClassLoadersChain() {
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}
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/**
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* Given the <tt>root</tt> loader, instantiate a chain
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* of loaders up to the given <tt>height</tt>.
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*
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* @see #getHeight()
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* @see #getRoot()
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* @see #getLoader(int)
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*/
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public ClassLoadersChain(ClassLoader root, int height) {
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if (height < 1)
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throw new IllegalArgumentException("wrong height: " + height);
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loaders = new ClassLoader [ height ];
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loaders[0] = root;
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for (int i=1; i<height; i++)
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loaders[i] = new DummyClassLoader(loaders[i-1]);
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}
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private ClassLoader loaders[]; // loaders[0] is the root
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/**
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* Return the loader found at the given <tt>level</tt>.
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* The value of <tt>level</tt> must be from <tt>0</tt>
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* to <tt>getHeight()-1</tt>.
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*
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* @see #getHeight()
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* @see #getRoot()
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*/
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public ClassLoader getLoader(int level) {
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return loaders[level];
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}
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/**
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* Return the chain's height.
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*
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* @see #ClassLoadersChain(ClassLoader,int)
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* @see #getLoader(int)
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*/
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public int getHeight() {
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return loaders.length;
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}
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/**
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* Return the chain's root loader.
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*
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* @see #ClassLoadersChain(ClassLoader,int)
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* @see #getLoader(int)
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*/
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public ClassLoader getRoot() {
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return loaders[0];
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}
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}
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