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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.path;
import com.yahoo.api.annotations.Beta;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
/**
* Represents a path as a list of elements. Immutable.
*
* @author Ulf Lilleengen
* @author bratseth
*/
@Beta
public final class Path {
private final String delimiter;
private final List<String> elements;
/** Creates an empty path */
private Path(String delimiter) {
this(List.of(), delimiter);
}
/**
* Create path with given elements
*
* @param elements a list of path elements
*/
private Path(List<String> elements, String delimiter) {
for (String element : elements)
if ("..".equals(element))
throw new IllegalArgumentException("'..' is not allowed in path");
this.elements = List.copyOf(elements);
this.delimiter = delimiter;
}
/** Creates a new path with the given segments. */
public static Path from(List<String> segments) {
return new Path(segments, "/");
}
/** Returns whether this path is an immediate child of the given path */
public boolean isChildOf(Path parent) {
return toString().startsWith(parent.toString()) && this.elements.size() -1 == parent.elements.size();
}
/**
* Add path elements by splitting based on delimiter and appending to elements.
*/
private static List<String> elementsOf(String path, String delimiter) {
return Arrays.stream(path.split(delimiter)).filter(e -> !"".equals(e)).toList();
}
/**
* Append an element to the path. Returns a new path with the given path appended.
*
* @param path the path to append to this
* @return the new path
*/
public Path append(String path) {
List<String> newElements = new ArrayList<>(this.elements);
newElements.addAll(elementsOf(path, delimiter));
return new Path(newElements, delimiter);
}
/**
* Appends a path to another path, thereby creating a new path with the provided path
* appended to this.
*
* @param path the path to append
* @return a new path with argument appended to it
*/
public Path append(Path path) {
List<String> newElements = new ArrayList<>(this.elements);
newElements.addAll(path.elements());
return new Path(newElements, delimiter);
}
/** Returns the name of this path element, typically the last element in the path string */
public String getName() {
if (elements.isEmpty()) return "";
return elements.get(elements.size() - 1);
}
/** Returns a string representation of the path represented by this */
public String getRelative() {
if (elements.isEmpty()) {
return "";
}
StringBuilder sb = new StringBuilder();
sb.append(elements.get(0));
for (int i = 1; i < elements.size(); i++) {
sb.append(delimiter);
sb.append(elements.get(i));
}
return sb.toString();
}
/** Returns the parent path: A path containing all elements of this except the last */
public Path getParentPath() {
ArrayList<String> parentElements = new ArrayList<>();
if (elements.size() > 1) {
for (int i = 0; i < elements.size() - 1; i++) {
parentElements.add(elements.get(i));
}
}
return new Path(parentElements, delimiter);
}
/** Returns the child path: A path containing all elements of this except the first */
public Path getChildPath() {
ArrayList<String> childElements = new ArrayList<>();
if (elements.size() > 1) {
for (int i = 1; i < elements.size(); i++) {
childElements.add(elements.get(i));
}
}
return new Path(childElements, delimiter);
}
/** Returns the last element in this, or the empty string if this path is empty */
public String last() {
if (elements.isEmpty()) return "";
return elements.get(elements.size() - 1);
}
/**
* Returns a new path with the last element replaced by the given element.
*
* @throws IllegalStateException if this path is empty
*/
public Path withLast(String element) {
if (element.contains(delimiter)) throw new IllegalArgumentException("single element cannot contain delimiter " + delimiter);
if (element.isEmpty()) throw new IllegalStateException("Cannot set the last element of an empty path");
List<String> newElements = new ArrayList<>(elements);
newElements.set(newElements.size() -1, element);
return new Path(newElements, delimiter);
}
/** Returns a string representation of this path where the delimiter is prepended */
public String getAbsolute() {
return delimiter + getRelative();
}
public boolean isRoot() {
return elements.isEmpty();
}
public Iterator<String> iterator() { return elements.iterator(); }
/** Returns an immutable list of the elements of this path in order */
public List<String> elements() { return elements; }
/** Returns this as a string */
@Override
public String toString() {
return getRelative();
}
/**
* Creates a path from a string. The string is treated as a relative path, and all redundant '/'-characters are
* stripped.
*
* @param path the relative path that this path should represent
* @return a path object that may be used with the application package
*/
public static Path fromString(String path) {
return fromString(path, "/");
}
/**
* Create a path from a string. The string is treated as a relative path, and all redundant delimiter-characters are
* stripped.
*
* @param path the relative path that this path should represent
* @return a path object that may be used with the application package
*/
public static Path fromString(String path, String delimiter) {
return new Path(elementsOf(path, delimiter), delimiter);
}
/**
* Create an empty root path with '/' delimiter.
*
* @return an empty root path that can be appended
*/
public static Path createRoot() {
return createRoot("/");
}
/**
* Create an empty root path with delimiter.
*
* @return an empty root path that can be appended
*/
public static Path createRoot(String delimiter) {
return new Path(delimiter);
}
public File toFile() { return new File(toString()); }
@Override
public int hashCode() {
return elements.hashCode();
}
@Override
public boolean equals(Object other) {
if (other instanceof Path) {
return getRelative().equals(((Path) other).getRelative());
}
return false;
}
}
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