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Avoid LinkedList performance issues through use of ArrayDeque

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Closes gh-25652
This commit is contained in:
Juergen Hoeller
2020-08-27 14:14:08 +02:00
parent 60fa704f78
commit 589060d10f
3 changed files with 34 additions and 28 deletions
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37
spring-beans/src/main/java/org/springframework/beans/factory/parsing/ParseState.java
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@@ -16,12 +16,12 @@
package org.springframework.beans.factory.parsing;
import java.util.LinkedList;
import java.util.ArrayDeque;
import org.springframework.lang.Nullable;
/**
* Simple {@link LinkedList}-based structure for tracking the logical position during
* Simple {@link ArrayDeque}-based structure for tracking the logical position during
* a parsing process. {@link Entry entries} are added to the LinkedList at
* each point during the parse phase in a reader-specific manner.
*
@@ -30,6 +30,7 @@ import org.springframework.lang.Nullable;
* error messages.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 2.0
*/
public final class ParseState {
@@ -40,45 +41,44 @@ public final class ParseState {
private static final char TAB = '\t';
/**
* Internal {@link LinkedList} storage.
* Internal {@link ArrayDeque} storage.
*/
private final LinkedList<Entry> state;
private final ArrayDeque<Entry> state;
/**
* Create a new {@code ParseState} with an empty {@link LinkedList}.
* Create a new {@code ParseState} with an empty {@link ArrayDeque}.
*/
public ParseState() {
this.state = new LinkedList<>();
this.state = new ArrayDeque<>();
}
/**
* Create a new {@code ParseState} whose {@link LinkedList} is a {@link Object#clone clone}
* Create a new {@code ParseState} whose {@link ArrayDeque} is a {@link Object#clone clone}
* of that of the passed in {@code ParseState}.
*/
@SuppressWarnings("unchecked")
private ParseState(ParseState other) {
this.state = (LinkedList<Entry>) other.state.clone();
this.state = other.state.clone();
}
/**
* Add a new {@link Entry} to the {@link LinkedList}.
* Add a new {@link Entry} to the {@link ArrayDeque}.
*/
public void push(Entry entry) {
this.state.push(entry);
}
/**
* Remove an {@link Entry} from the {@link LinkedList}.
* Remove an {@link Entry} from the {@link ArrayDeque}.
*/
public void pop() {
this.state.pop();
}
/**
* Return the {@link Entry} currently at the top of the {@link LinkedList} or
* {@code null} if the {@link LinkedList} is empty.
* Return the {@link Entry} currently at the top of the {@link ArrayDeque} or
* {@code null} if the {@link ArrayDeque} is empty.
*/
@Nullable
public Entry peek() {
@@ -100,15 +100,17 @@ public final class ParseState {
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (int x = 0; x < this.state.size(); x++) {
if (x > 0) {
int i = 0;
for (ParseState.Entry entry : this.state) {
if (i > 0) {
sb.append('\n');
for (int y = 0; y < x; y++) {
for (int j = 0; j < i; j++) {
sb.append(TAB);
}
sb.append("-> ");
}
sb.append(this.state.get(x));
sb.append(entry);
i++;
}
return sb.toString();
}
@@ -118,7 +120,6 @@ public final class ParseState {
* Marker interface for entries into the {@link ParseState}.
*/
public interface Entry {
}
}