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/**
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* RAII v Javě
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* Copyright © 2014 František Kučera (frantovo.cz)
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package cz.frantovo.priklady.raii;
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/**
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*
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* @author Ing. František Kučera (frantovo.cz)
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*/
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public class RAIIDemo {
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public static void main(String[] args) {
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/**
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* Bez výjimek:
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*/
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try {
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try (Zdroj a = new Zdroj("a", false, false, false)) {
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try (Zdroj b = new Zdroj("b", false, false, false)) {
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try (Zdroj c = new Zdroj("c", false, false, false)) {
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a.něcoDělej();
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b.něcoDělej();
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c.něcoDělej();
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} // končí rozsah platnosti proměnné c → volá se c.close()
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} // b.close()
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} // a.close()
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} catch (ChybaVytváření | ChybaZavírání | ChybaDělání e) {
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System.err.println(e);
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}
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System.err.println("--------------------------------");
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/**
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* S výjimkami:
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*/
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try {
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try (Zdroj a = new Zdroj("a", false, false, true)) {
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try (Zdroj b = new Zdroj("b", false, false, true)) {
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try (Zdroj c = new Zdroj("c", false, true, true)) {
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a.něcoDělej();
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b.něcoDělej();
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c.něcoDělej();
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}
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}
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}
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} catch (ChybaVytváření | ChybaZavírání | ChybaDělání e) {
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System.err.println(e);
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}
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System.gc(); // aby se GC vůbec stihl spustit
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čekej(); // aby GC stihl zavolat finalize()
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}
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private static void čekej() {
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try {
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Thread.sleep(100);
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} catch (InterruptedException ex) {
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}
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}
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}
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