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A feature describes an OSGi system
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with this
* work for additional information regarding copyright ownership. The ASF
* licenses this file to You under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package org.apache.jackrabbit.commons.flat;
import org.apache.jackrabbit.commons.flat.TreeTraverser.ErrorHandler;
import org.apache.jackrabbit.commons.flat.TreeTraverser.InclusionPolicy;
import javax.jcr.ItemExistsException;
import javax.jcr.Node;
import javax.jcr.NodeIterator;
import javax.jcr.PathNotFoundException;
import javax.jcr.Property;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.Value;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Set;
/**
*
* This class serves as main entry point for obtaining sequences of {@link Node}
* s and {@link Property}s. It provides factory methods for creating
* {@link NodeSequence}s and {@link PropertySequence}s.
*
*
*
* NodeSequence and PropertySequence instances provide a flat representation of
* a JCR hierarchy rooted at a certain node. They allow iterating over all
* items, retrieving items by key, checking whether a given key is mapped,
* adding new items and removing existing items.
*
*
*
* The specifics of the mapping from the flat representation to the JCR
* hierarchy are delegated to a {@link TreeManager}. Particularly the
* TreeManager specifies the order of the items when retrieved as sequence and
* when and how to add and remove intermediate nodes when new items are inserted
* or removed.
*
*
*
* An {@link ErrorHandler} is used to handle exceptions which occur while
* traversing the hierarchy.
*
*
* @see TreeTraverser
* @see NodeSequence
* @see PropertySequence
* @see TreeManager
*/
public abstract class ItemSequence {
/**
* The {@link TreeManager} instance managing the mapping between the
* sequence view and the JCR hierarchy.
*/
protected final TreeManager treeManager;
/**
* The {@link ErrorHandler} instance used for handling exceptions occurring
* while traversing the hierarchy.
*/
protected final ErrorHandler errorHandler;
/**
* @see TreeManager#getRoot()
*/
protected final Node root;
/**
* @see TreeManager#getOrder()
*/
protected final Comparator order;
/**
* @see TreeManager#getAutoSave()
*/
protected final boolean autoSave;
/**
* Create a new {@link ItemSequence} instance.
*
* @param treeManager The {@link TreeManager} for managing the mapping
* between the sequence view and the JCR hierarchy.
* @param errorHandler The {@link ErrorHandler} for handling exceptions
* occurring while traversing the hierarchy.
* @throws IllegalArgumentException If either treeManager is
* null or {@link TreeManager#getRoot()} return
* null or {@link TreeManager#getOrder()} return
* null.
*/
protected ItemSequence(TreeManager treeManager, ErrorHandler errorHandler) {
super();
if (treeManager == null) {
throw new IllegalArgumentException("tree manager must not be null");
}
if (treeManager.getRoot() == null) {
throw new IllegalArgumentException("root must not be null");
}
if (treeManager.getOrder() == null) {
throw new IllegalArgumentException("order must not be null");
}
this.treeManager = treeManager;
this.errorHandler = errorHandler;
this.root = treeManager.getRoot();
this.order = treeManager.getOrder();
this.autoSave = treeManager.getAutoSave();
}
/**
* Create a new {@link NodeSequence} instance.
*
* @param treeManager The {@link TreeManager} for managing the mapping
* between the sequence view and the JCR hierarchy.
* @param errorHandler The {@link ErrorHandler} for handling exceptions
* occurring while
* @return
*/
public static NodeSequence createNodeSequence(TreeManager treeManager, ErrorHandler errorHandler) {
return new NodeSequenceImpl(treeManager, errorHandler);
}
/**
* Create a new {@link NodeSequence} instance.
*
* @param treeManager The {@link TreeManager} for managing the mapping
* between the sequence view and the JCR hierarchy.
* @return
*/
public static NodeSequence createNodeSequence(TreeManager treeManager) {
return new NodeSequenceImpl(treeManager, ErrorHandler.IGNORE);
}
/**
* Create a new {@link PropertySequence} instance.
*
* @param treeManager The {@link TreeManager} for managing the mapping
* between the sequence view and the JCR hierarchy.
* @param errorHandler The {@link ErrorHandler} for handling exceptions
* occurring while
* @return
*/
public static PropertySequence createPropertySequence(TreeManager treeManager, ErrorHandler errorHandler) {
return new PropertySequenceImpl(treeManager, errorHandler);
}
/**
* Create a new {@link PropertySequence} instance.
*
* @param treeManager The {@link TreeManager} for managing the mapping
* between the sequence view and the JCR hierarchy.
* @return
*/
public static PropertySequence createPropertySequence(TreeManager treeManager) {
return new PropertySequenceImpl(treeManager, ErrorHandler.IGNORE);
}
/**
* Create a new {@link NodeSequence} instance with the same parameterization
* as this instance.
*
* @return
*/
public NodeSequence getNodeSequence() {
return new NodeSequenceImpl(treeManager, errorHandler);
}
/**
* Create a new {@link PropertySequence} instance with the same
* parametrization as this instance.
*
* @return
*/
public PropertySequence getPropertySequence() {
return new PropertySequenceImpl(treeManager, errorHandler);
}
// -----------------------------------------------------< internal >---
/**
* Returns the parent node for the given key. When the key is not present in
* this sequence already, the returned node is the node that would contain
* that key if it where present.
*/
protected abstract Node getParent(String key) throws RepositoryException;
/**
* Returns the predecessor node for the given
* key. That is the node
* whose key directly precedes the passed key in the order
* determined by {@link TreeManager#getOrder()}. There are two cases:
*
* - A node with the given
key is mapped: then that node is
* returned.
* - A node with the given
key is not mapped: the the node
* where that would contain that key if present is returned.
*
*/
protected final Node getPredecessor(String key) throws RepositoryException {
Node p = root;
Node n;
while ((n = getPredecessor(p, key)) != null) {
p = n;
}
return p;
}
/**
* Returns the direct predecessor of key amongst
* node's child nodes wrt. to {@link TreeManager#getOrder()}.
* Returns null if either node has no child nodes
* or node is a leaf (see {@link TreeManager#isLeaf(Node)}) or
* key is smaller than all the keys of all child nodes of
* node.
*/
protected final Node getPredecessor(Node node, String key) throws RepositoryException {
if (!node.hasNodes() || treeManager.isLeaf(node)) {
return null;
}
// Shortcut for exact match
try {
return node.getNode(key);
}
catch (PathNotFoundException ignore) { }
// Search for direct predecessor of key in the nodes children
// todo performance: for ordered nodes use binary search
NodeIterator childNodes = node.getNodes();
Node p = null;
while (childNodes.hasNext()) {
Node n = childNodes.nextNode();
String childKey = n.getName();
if (order.compare(key, childKey) > 0 && (p == null || order.compare(childKey, p.getName()) > 0)) {
p = n;
}
}
return p;
}
/**
* Returns the successor node for the given
* key. That is the node
* whose key directly succeeds the passed key in the order
* determined by {@link TreeManager#getOrder()}. There are two cases:
*
* - A node with the given
key is mapped: then that node is
* returned.
* - A node with the given
key is not mapped: the the node
* where that would contain that key if present is returned.
*
*/
protected final Node getSuccessor(Node node, String key) throws RepositoryException {
if (!node.hasNodes() || treeManager.isLeaf(node)) {
return null;
}
// Shortcut for exact match
try {
return node.getNode(key);
}
catch (PathNotFoundException ignore) { }
// Search for direct successor of key in the nodes children
// todo performance: for ordered nodes use binary search
NodeIterator childNodes = node.getNodes();
Node s = null;
while (childNodes.hasNext()) {
Node n = childNodes.nextNode();
String childKey = n.getName();
if (order.compare(key, childKey) < 0 && (s == null || order.compare(childKey, s.getName()) < 0)) {
s = n;
}
}
return s;
}
/**
* Returns the node with the minimal key wrt. {@link TreeManager#getOrder()}.
* For the empty sequence this is {@link TreeManager#getRoot()}.
*/
protected final Node getMinimal() throws RepositoryException {
Node p = null;
Node n = root;
while ((n = getMinimal(n)) != null) {
p = n;
}
return p;
}
/**
* Returns the node amongst the child nodes of node whose key
* is minimal wrt. {@link TreeManager#getOrder()}. Returns null
* id either node has no child nodes or node is a
* leaf (see {@link TreeManager#isLeaf(Node)}).
*/
protected final Node getMinimal(Node node) throws RepositoryException {
if (!node.hasNodes() || treeManager.isLeaf(node)) {
return null;
}
// Search for minimal key in the nodes children
// todo performance: for ordered nodes use binary search
NodeIterator childNodes = node.getNodes();
Node p = childNodes.nextNode();
String minKey = p.getName();
while (childNodes.hasNext()) {
Node n = childNodes.nextNode();
if (order.compare(n.getName(), minKey) < 0) {
p = n;
minKey = p.getName();
}
}
return p;
}
/**
* Rename the path of the node with the minimal key. That is, assuming
* node is the node with the minimal key (see
* {@link #getMinimal()}), this method renames every segment of the path of
* node up to {@link TreeManager#getRoot()} to key
* . Note: If node is not the node with the minimal
* key, the behavior of this method is not specified.
*/
protected final void renamePath(Node node, String key) throws RepositoryException {
if (!treeManager.isRoot(node)) {
Node p = node.getParent();
renamePath(p, key);
Session s = node.getSession();
s.move(node.getPath(), p.getPath() + "/" + key);
// If orderable, move to first child node
if (p.getPrimaryNodeType().hasOrderableChildNodes()) {
p.orderBefore(key, p.getNodes().nextNode().getName());
}
}
}
protected static class NodeSequenceImpl extends ItemSequence implements NodeSequence {
private final InclusionPolicy inclusionPolicy = new InclusionPolicy() {
public boolean include(Node node) {
try {
return treeManager.isLeaf(node);
}
catch (RepositoryException e) {
return false;
}
}
};
public NodeSequenceImpl(TreeManager treeManager, ErrorHandler errorHandler) {
super(treeManager, errorHandler);
}
public Iterator iterator() {
return TreeTraverser.nodeIterator(root, errorHandler, inclusionPolicy);
}
public Node getItem(String key) throws RepositoryException {
return getParent(key).getNode(key);
}
public boolean hasItem(String key) throws RepositoryException {
return getParent(key).hasNode(key);
}
public Node addNode(String key, String primaryNodeTypeName) throws RepositoryException {
Node parent = getOrCreateParent(key);
if (parent.hasNode(key)) {
throw new ItemExistsException(key);
}
Node n;
if (parent.getPrimaryNodeType().hasOrderableChildNodes()) {
Node dest = getSuccessor(parent, key);
n = parent.addNode(key, primaryNodeTypeName);
parent.orderBefore(key, dest == null ? null : dest.getName());
}
else {
n = parent.addNode(key, primaryNodeTypeName);
}
treeManager.split(this, parent, n);
if (autoSave) {
parent.getSession().save();
}
return n;
}
public void removeNode(String key) throws RepositoryException {
Node parent = getParent(key);
Node n = parent.getNode(key);
n.remove();
treeManager.join(this, parent, n);
if (autoSave) {
parent.getSession().save();
}
}
@Override
public Node getParent(String key) throws RepositoryException {
Node p = getPredecessor(key);
if (treeManager.isLeaf(p) && !treeManager.isRoot(p)) {
return p.getParent();
}
else {
return p;
}
}
private Node getOrCreateParent(String key) throws RepositoryException {
Node p = getParent(key);
if (treeManager.isRoot(p)) {
Node min = getMinimal();
if (min != null) {
p = min.getParent();
renamePath(p, key);
}
}
return p;
}
}
protected static class PropertySequenceImpl extends ItemSequence implements PropertySequence {
private final InclusionPolicy inclusionPolicy = new InclusionPolicy() {
private final Set ignoredProperties = treeManager.getIgnoredProperties();
public boolean include(Property property) {
try {
return !ignoredProperties.contains(property.getName());
}
catch (RepositoryException e) {
return false;
}
}
};
public PropertySequenceImpl(TreeManager treeManager, ErrorHandler errorHandler) {
super(treeManager, errorHandler);
}
public Iterator iterator() {
return TreeTraverser.propertyIterator(getNodeSequence().iterator(), errorHandler, inclusionPolicy);
}
public Property getItem(String key) throws RepositoryException {
return getParent(key).getProperty(key);
}
public boolean hasItem(String key) throws RepositoryException {
return getParent(key).hasProperty(key);
}
public Property addProperty(String key, Value value) throws RepositoryException {
Node parent = getOrCreateParent(key);
if (parent.hasProperty(key)) {
throw new ItemExistsException(key);
}
Property p = parent.setProperty(key, value);
treeManager.split(this, parent, p);
if (autoSave) {
p.getSession().save();
}
return p;
}
public void removeProperty(String key) throws RepositoryException {
Node parent = getParent(key);
Property p = parent.getProperty(key);
p.remove();
treeManager.join(this, parent, p);
if (autoSave) {
parent.getSession().save();
}
}
@Override
public Node getParent(String key) throws RepositoryException {
return getPredecessor(key);
}
private Node getOrCreateParent(String key) throws RepositoryException {
Node p = getParent(key);
if (treeManager.isRoot(p)) {
Node min = getMinimal();
if (min != null) {
p = min;
renamePath(p, key);
}
}
return p;
}
}
}