| /* |
| * 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.oak.plugins.tree; |
| |
| import org.apache.jackrabbit.oak.api.PropertyState; |
| import org.apache.jackrabbit.oak.api.Root; |
| import org.apache.jackrabbit.oak.api.Tree; |
| import org.apache.jackrabbit.oak.commons.PathUtils; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import static com.google.common.base.Objects.toStringHelper; |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static org.apache.jackrabbit.oak.commons.PathUtils.elements; |
| import static org.apache.jackrabbit.oak.commons.PathUtils.isAbsolute; |
| |
| /** |
| * A {@code TreeLocation} denotes a location inside a tree. |
| * <p> |
| * It can either refer to a inner node (that is a {@link Tree}), to a leaf (that is a |
| * {@link PropertyState}) or to an invalid location which refers to neither of the former. |
| * {@code TreeLocation} instances provide methods for navigating trees such that navigation |
| * always results in new {@code TreeLocation} instances. Navigation never fails. Errors are |
| * deferred until the underlying item itself is accessed. That is, if a {@code TreeLocation} |
| * points to an item which does not exist or is unavailable otherwise (i.e. due to access |
| * control restrictions) accessing the tree will return {@code null} at this point. |
| */ |
| public abstract class TreeLocation { |
| |
| /** |
| * Create a new {@code TreeLocation} instance for a {@code tree} |
| */ |
| public static TreeLocation create(@NotNull Tree tree) { |
| return new NodeLocation(tree); |
| } |
| |
| /** |
| * Create a new {@code TreeLocation} instance for the item |
| * at the given {@code path} in {@code root}. |
| */ |
| public static TreeLocation create(Root root, String path) { |
| checkArgument(isAbsolute(path)); |
| TreeLocation location = create(root.getTree(PathUtils.ROOT_PATH)); |
| for (String name : elements(path)) { |
| location = location.getChild(name); |
| } |
| return location; |
| } |
| |
| /** |
| * Equivalent to {@code create(root, "/")} |
| */ |
| public static TreeLocation create(Root root) { |
| return create(root, PathUtils.ROOT_PATH); |
| } |
| |
| /** |
| * Navigate to the parent or an invalid location for the root of the hierarchy. |
| * @return a {@code TreeLocation} for the parent of this location. |
| */ |
| @NotNull |
| public abstract TreeLocation getParent(); |
| |
| /** |
| * Determine whether the underlying {@link org.apache.jackrabbit.oak.api.Tree} or |
| * {@link org.apache.jackrabbit.oak.api.PropertyState} for this {@code TreeLocation} |
| * is available. |
| * @return {@code true} if the underlying item is available and has not been disconnected. |
| * @see org.apache.jackrabbit.oak.api.Tree#exists() |
| */ |
| public abstract boolean exists(); |
| |
| /** |
| * The name of this location |
| * @return name |
| */ |
| @NotNull |
| public abstract String getName(); |
| |
| /** |
| * The path of this location |
| * @return path |
| */ |
| @NotNull |
| public abstract String getPath(); |
| |
| /** |
| * Remove the underlying item. |
| * |
| * @return {@code true} if the item was removed, {@code false} otherwise. |
| */ |
| public abstract boolean remove(); |
| |
| /** |
| * Navigate to a child of the given {@code name}. |
| * @param name name of the child |
| * @return this default implementation return a non existing location |
| */ |
| @NotNull |
| public TreeLocation getChild(String name) { |
| return new NullLocation(this, name); |
| } |
| |
| /** |
| * Get the underlying {@link org.apache.jackrabbit.oak.api.Tree} for this {@code TreeLocation}. |
| * @return this default implementation return {@code null}. |
| */ |
| @Nullable |
| public Tree getTree() { |
| return null; |
| } |
| |
| /** |
| * Get the underlying {@link org.apache.jackrabbit.oak.api.PropertyState} for this {@code TreeLocation}. |
| * @return this default implementation return {@code null}. |
| */ |
| @Nullable |
| public PropertyState getProperty() { |
| return null; |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this).add("path", getPath()).toString(); |
| } |
| |
| /** |
| * This {@code TreeLocation} refers to child tree in a |
| * {@code Tree}. |
| */ |
| private static class NodeLocation extends TreeLocation { |
| private final Tree tree; |
| |
| public NodeLocation(Tree tree) { |
| this.tree = tree; |
| } |
| |
| @NotNull |
| @Override |
| public TreeLocation getParent() { |
| return tree.isRoot() |
| ? NullLocation.NULL |
| : new NodeLocation(tree.getParent()); |
| } |
| |
| @NotNull |
| @Override |
| public TreeLocation getChild(String name) { |
| if (tree.hasProperty(name)) { |
| return new PropertyLocation(tree, name); |
| } else { |
| return new NodeLocation(tree.getChild(name)); |
| } |
| } |
| |
| @Override |
| public boolean exists() { |
| return tree.exists(); |
| } |
| |
| @NotNull |
| @Override |
| public String getName() { |
| return tree.getName(); |
| } |
| |
| @Override |
| public Tree getTree() { |
| return exists() ? tree : null; |
| } |
| |
| @NotNull |
| @Override |
| public String getPath() { |
| return tree.getPath(); |
| } |
| |
| @Override |
| public boolean remove() { |
| return exists() && tree.remove(); |
| } |
| } |
| |
| /** |
| * This {@code TreeLocation} refers to property in a |
| * {@code Tree}. |
| */ |
| private static class PropertyLocation extends TreeLocation { |
| private final Tree parent; |
| private final String name; |
| |
| public PropertyLocation(Tree parent, String name) { |
| this.parent = parent; |
| this.name = name; |
| } |
| |
| @NotNull |
| @Override |
| public TreeLocation getParent() { |
| return new NodeLocation(parent); |
| } |
| |
| @Override |
| public boolean exists() { |
| return parent.hasProperty(name); |
| } |
| |
| @NotNull |
| @Override |
| public String getName() { |
| return name; |
| } |
| |
| @Override |
| public PropertyState getProperty() { |
| return parent.getProperty(name); |
| } |
| |
| @NotNull |
| @Override |
| public String getPath() { |
| return PathUtils.concat(parent.getPath(), name); |
| } |
| |
| @Override |
| public boolean remove() { |
| parent.removeProperty(name); |
| return true; |
| } |
| } |
| |
| /** |
| * This {@code TreeLocation} refers to an invalid location in a tree. That is |
| * to a location where no item resides. |
| */ |
| private static final class NullLocation extends TreeLocation { |
| public static final NullLocation NULL = new NullLocation(); |
| |
| private final TreeLocation parent; |
| private final String name; |
| |
| public NullLocation(TreeLocation parent, String name) { |
| this.parent = parent; |
| this.name = name; |
| } |
| |
| private NullLocation() { |
| this.parent = this; |
| this.name = ""; |
| } |
| |
| @NotNull |
| @Override |
| public TreeLocation getParent() { |
| return parent; |
| } |
| |
| /** |
| * @return {@code false} |
| */ |
| @Override |
| public boolean exists() { |
| return false; |
| } |
| |
| @NotNull |
| @Override |
| public String getName() { |
| return name; |
| } |
| |
| @NotNull |
| @Override |
| public String getPath() { |
| return parent == this ? "" : PathUtils.concat(parent.getPath(), name); |
| } |
| |
| /** |
| * @return Always {@code false}. |
| */ |
| @Override |
| public boolean remove() { |
| return false; |
| } |
| |
| } |
| } |