org.opencms.util.CmsPathTree Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.util;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
/**
* Tree used to represent file system like data structures.
*
* A tree consists of a (possibly empty) value and a map from child names to subtrees.
*
* @param
the type of path components
* @param the element type stored in the tree
*
*/
public class CmsPathTree {
/** The map from child names to children. */
private Map> m_children = Maps.newHashMap();
/** The value (may be null). */
private V m_value;
/**
* Collect all descendant values in the given collection.
*
* @param target the collection in which to store the descendant values
*/
public void collectEntries(Collection target) {
if (m_value != null) {
target.add(m_value);
}
for (CmsPathTree child : m_children.values()) {
child.collectEntries(target);
}
}
/**
* Finds the node for the given path, and returns it or null if node was found.
*
* @param path the path
* @return the node for the path
*/
public CmsPathTree findNode(List path) {
List
pathToConsume = Lists.newLinkedList(path);
CmsPathTree descendant = findNodeInternal(pathToConsume);
if (!pathToConsume.isEmpty()) {
return null;
} else {
return descendant;
}
}
/**
* Gets the child for the given path component.
*
* @param pathPart the path component
*
* @return the child for the given path component (may be null)
*/
public CmsPathTree getChild(P pathPart) {
return m_children.get(pathPart);
}
/**
* Returns the values for the direct children of this node.
*
* @return the values for the direct children
*/
public List getChildValues() {
List result = Lists.newArrayList();
for (CmsPathTree child : m_children.values()) {
if (child.m_value != null) {
result.add(child.m_value);
}
}
return result;
}
/**
* Gets the child values for the given path.
*
* @param path the path
*
* @return the child values
*/
public List getChildValues(List path) {
CmsPathTree descendant = findNode(path);
if (descendant != null) {
return descendant.getChildValues();
} else {
return Collections.emptyList();
}
}
/**
* Gets the descendant values.
*
* @param path the path
* @return the descendant values
*/
public List getDescendantValues(List path) {
CmsPathTree node = findNode(path);
List result = Lists.newArrayList();
if (node != null) {
node.collectEntries(result);
}
return result;
}
/**
* Gets the value for this node (may be null).
*
* @return the value
*/
public V getValue() {
return m_value;
}
/**
* Gets the value for the sub-path given, starting from this node.
*
* @param path the path
* @return the value for the node
*/
public V getValue(List
path) {
CmsPathTree node = findNode(path);
if (node != null) {
return node.m_value;
} else {
return null;
}
}
/**
* Sets the value for the sub-path given, starting from this node.
*
* @param path the path
* @param value the value to set
*/
public void setValue(List
path, V value) {
ensureNode(path).setValue(value);
}
/**
* Sets the value for this node.
*
* @param value the value for the node
*/
public void setValue(V value) {
m_value = value;
}
/**
* Returns the node for the given path, creating all nodes on the way if they don't already exist.
*
* @param path the path for which to make sure a node exists
*
* @return the node for the path
*/
private CmsPathTree ensureNode(List path) {
List
pathToConsume = Lists.newLinkedList(path);
CmsPathTree lastExistingNode = findNodeInternal(pathToConsume);
CmsPathTree currentNode = lastExistingNode;
for (P pathPart : pathToConsume) {
CmsPathTree child = new CmsPathTree();
currentNode.m_children.put(pathPart, child);
currentNode = child;
}
return currentNode;
}
/**
* Tries to traverse the descendants of this node along the given path,
* and returns the last existing node along that path.
*
* The given path is modified so that only the part of the path for which no nodes can be found
* remains.
*
* @param pathToConsume the path to find (will be modified by this method)
* @return the last node found along the descendant chain for the path
*/
private CmsPathTree findNodeInternal(List pathToConsume) {
Iterator
iter = pathToConsume.iterator();
CmsPathTree currentNode = this;
while (iter.hasNext()) {
CmsPathTree child = currentNode.getChild(iter.next());
if (child != null) {
iter.remove();
currentNode = child;
} else {
return currentNode;
}
}
return currentNode;
}
}