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Merge pull request #3855 from volodya-lombrozo/3840_tr_stepped
feat(#3840): Fix Concurrency Issue Related to `TrStepped`
2 parents a0c3048 + 6a85eb9 commit e80f520

2 files changed

Lines changed: 163 additions & 6 deletions

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‎eo-parser/src/main/java/org/eolang/parser/TrStepped.java‎

Lines changed: 71 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -31,13 +31,15 @@
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import com.yegor256.xsline.TrEnvelope;
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import com.yegor256.xsline.TrLambda;
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import com.yegor256.xsline.Train;
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import java.util.concurrent.CountDownLatch;
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import org.cactoos.Scalar;
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import org.cactoos.io.ResourceOf;
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import org.cactoos.scalar.Sticky;
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import org.cactoos.scalar.Synced;
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import org.cactoos.text.TextOf;
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/**
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* Trains that adds sheet names that were processed.
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* Train that adds sheet names that were processed.
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*
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* @since 0.1
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*/
@@ -47,26 +49,39 @@ final class TrStepped extends TrEnvelope {
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* Apply changes to each XML after processing.
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*/
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private static final Scalar<XSL> STEPPED = new Sticky<>(
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() -> new XSLDocument(
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new TextOf(
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new ResourceOf("org/eolang/parser/_stepped.xsl")
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).asString()
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new Once<XSL>(
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() -> new XSLDocument(
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new TextOf(
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new ResourceOf("org/eolang/parser/_stepped.xsl")
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).asString()
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)
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)
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);
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/**
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* Ctor.
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*
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* @param train Original train
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*/
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TrStepped(final Train<Shift> train) {
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this(train, TrStepped.STEPPED);
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}
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/**
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* Ctor.
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*
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* @param train Original train
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* @param stepped XSL to apply
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*/
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TrStepped(final Train<Shift> train, final Scalar<XSL> stepped) {
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super(
6378
new TrLambda(
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train,
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shift -> new StAfter(
6681
shift,
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new StLambda(
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shift::uid,
69-
(pos, xml) -> TrStepped.STEPPED.value()
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(pos, xml) -> new Synced<>(stepped).value()
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.with("step", pos)
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.with("sheet", shift.uid())
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.transform(xml)
@@ -75,4 +90,54 @@ final class TrStepped extends TrEnvelope {
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)
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);
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}
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/**
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* Scalar that loads the value only once.
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*
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* @param <T> Type of the value
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* @since 0.51
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*/
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static final class Once<T> implements Scalar<T> {
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/**
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* Origin scalar.
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*/
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private final Scalar<T> origin;
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/**
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* Latch to count down.
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*/
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private final CountDownLatch latch;
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/**
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* Ctor.
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*
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* @param origin Origin scalar
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*/
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Once(final Scalar<T> origin) {
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this(origin, new CountDownLatch(1));
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}
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/**
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* Ctor.
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*
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* @param origin Origin scalar
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* @param latch Latch to count down
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*/
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private Once(final Scalar<T> origin, final CountDownLatch latch) {
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this.origin = origin;
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this.latch = latch;
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}
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@Override
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public T value() throws Exception {
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if (this.latch.getCount() < 1) {
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throw new IllegalStateException(
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String.format("Resource '%s' should be loaded only once", this.origin)
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);
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}
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this.latch.countDown();
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return this.origin.value();
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}
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}
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}

‎eo-parser/src/test/java/org/eolang/parser/TrSteppedTest.java‎

Lines changed: 92 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,92 @@
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/*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016-2025 Objectionary.com
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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package org.eolang.parser;
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import com.jcabi.matchers.XhtmlMatchers;
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import com.jcabi.xml.XML;
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import com.jcabi.xml.XMLDocument;
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import com.jcabi.xml.XSL;
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import com.jcabi.xml.XSLDocument;
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import com.yegor256.Together;
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import com.yegor256.xsline.Shift;
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import com.yegor256.xsline.StClasspath;
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import com.yegor256.xsline.TrDefault;
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import com.yegor256.xsline.Xsline;
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import org.cactoos.io.ResourceOf;
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import org.cactoos.scalar.Sticky;
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import org.cactoos.text.TextOf;
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import org.hamcrest.MatcherAssert;
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import org.junit.jupiter.api.RepeatedTest;
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import org.junit.jupiter.api.Test;
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/**
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* Test cases for {@link TrStepped}.
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*
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* @since 0.51
47+
*/
48+
final class TrSteppedTest {
49+
50+
@Test
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void addsSheetName() {
52+
MatcherAssert.assertThat(
53+
"We expect the sheet name to be added",
54+
new Xsline(
55+
new TrStepped(
56+
new TrDefault<Shift>().with(
57+
new StClasspath("/org/eolang/parser/print/wrap-data.xsl")
58+
)
59+
)
60+
).pass(new XMLDocument("<program><concurrency>no</concurrency></program>")).toString(),
61+
XhtmlMatchers.hasXPath("/program/sheets/sheet[text()='wrap-data']")
62+
);
63+
}
64+
65+
@RepeatedTest(10)
66+
void addsSheetNameConcurrently() {
67+
final XML doc = new XMLDocument("<program><concurrency>yes</concurrency></program>");
68+
final Sticky<XSL> loading = new Sticky<>(
69+
new TrStepped.Once<XSL>(
70+
() -> new XSLDocument(
71+
new TextOf(
72+
() -> new ResourceOf("org/eolang/parser/_stepped.xsl").stream()
73+
).asString()
74+
)
75+
)
76+
);
77+
MatcherAssert.assertThat(
78+
"We expect the sheet name to be added successfully in concurrent environment",
79+
new Together<>(
80+
i -> new Xsline(
81+
new TrStepped(
82+
new TrDefault<Shift>().with(
83+
new StClasspath("/org/eolang/parser/print/wrap-data.xsl")
84+
),
85+
loading
86+
)
87+
).pass(doc).toString()
88+
).iterator().next(),
89+
XhtmlMatchers.hasXPath("/program/sheets/sheet[text()='wrap-data']")
90+
);
91+
}
92+
}

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