Java example source code file (StringFoldingTest.java)

This example Java source code file (StringFoldingTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

arraylist, assertionerror, charsequence, compilationunittree, expected, folded, ioexception, iterable, javactask, javasource, net, network, simplejavafileobject, string, stringfoldingtest, util, xdallowstringfolding\=false

The StringFoldingTest.java Java example source code

/*
 * Copyright (c) 2011, 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.
 */

/*
 * @test
 * @bug 7068902
 * @summary verify that string folding can be enabled or disabled
 */

import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.util.JavacTask;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.ToolProvider;

public class StringFoldingTest {
    final JavaCompiler tool;
    final JavaSource source;

    public StringFoldingTest() {
        tool = ToolProvider.getSystemJavaCompiler();
        source = new JavaSource();
    }

    static class JavaSource extends SimpleJavaFileObject {

        final static String source =
                "class C {String X=\"F\" + \"O\" + \"L\" + \"D\" + \"E\" + \"D\";}";

        JavaSource() {
            super(URI.create("myfo:/C.java"), JavaFileObject.Kind.SOURCE);
        }

        @Override
        public CharSequence getCharContent(boolean ignoreEncodingErrors) {
            return source;
        }
    }

    public static void main(String... args) throws IOException {
        StringFoldingTest t = new StringFoldingTest();
        t.run(false);
        t.run(true);
    }

    void run(boolean disableStringFolding) throws IOException {
        List<String> argsList = new ArrayList();
        if (disableStringFolding) {
            argsList.add("-XDallowStringFolding=false");
        }
        JavacTask ct = (JavacTask)tool.getTask(null, null, null,
                argsList,
                null,
                Arrays.asList(source));
        Iterable<? extends CompilationUnitTree> trees = ct.parse();
        String text = trees.toString();
        System.out.println(text);

        if (disableStringFolding) {
            if (text.contains("FOLDED")) {
                throw new AssertionError("Expected string folding");
            }
        } else {
            if (!text.contains("FOLDED")) {
                throw new AssertionError("Expected no string folding");
            }
        }
    }
}