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/**
* Copyright (C) 2006-2015 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* Licensed 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 com.phloc.commons.tree.utils.walk;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.annotations.PresentForCodeCoverage;
import com.phloc.commons.hierarchy.DefaultHierarchyWalkerCallback;
import com.phloc.commons.hierarchy.IHierarchyWalkerCallback;
import com.phloc.commons.parent.IChildrenProvider;
import com.phloc.commons.parent.impl.ChildrenProviderHasChildren;
import com.phloc.commons.tree.IBasicTree;
import com.phloc.commons.tree.IBasicTreeItem;
/**
* Iterate all nodes of a tree, or a tree element using a custom callback
* mechanism.
*
* @author Philip Helger
*/
@Immutable
public final class TreeWalker
{
@PresentForCodeCoverage
@SuppressWarnings ("unused")
private static final TreeWalker s_aInstance = new TreeWalker ();
private TreeWalker ()
{}
private static > void _walkTree (@Nonnull final ITEMTYPE aTreeItem,
@Nonnull final IChildrenProvider aChildrenProvider,
@Nonnull final IHierarchyWalkerCallback aCallback)
{
aCallback.onItemBeforeChildren (aTreeItem);
if (aChildrenProvider.hasChildren (aTreeItem))
for (final ITEMTYPE aChildItem : aChildrenProvider.getChildren (aTreeItem))
{
aCallback.onLevelDown ();
// recursive call
_walkTree (aChildItem, aChildrenProvider, aCallback);
aCallback.onLevelUp ();
}
aCallback.onItemAfterChildren (aTreeItem);
}
public static > void walkTree (@Nonnull final IBasicTree aTree,
@Nonnull final IHierarchyWalkerCallback aCallback)
{
walkTree (aTree, new ChildrenProviderHasChildren (), aCallback);
}
public static > void walkTree (@Nonnull final IBasicTree aTree,
@Nonnull final IChildrenProvider aChildrenProvider,
@Nonnull final IHierarchyWalkerCallback aCallback)
{
ValueEnforcer.notNull (aTree, "Tree");
walkSubTree (aTree.getRootItem (), aChildrenProvider, aCallback);
}
public static > void walkTreeData (@Nonnull final IBasicTree aTree,
@Nonnull final IHierarchyWalkerCallback aDataCallback)
{
walkTreeData (aTree, new ChildrenProviderHasChildren (), aDataCallback);
}
public static > void walkTreeData (@Nonnull final IBasicTree aTree,
@Nonnull final IChildrenProvider aChildrenProvider,
@Nonnull final IHierarchyWalkerCallback aDataCallback)
{
ValueEnforcer.notNull (aTree, "Tree");
walkSubTreeData (aTree.getRootItem (), aChildrenProvider, aDataCallback);
}
public static > void walkSubTree (@Nonnull final ITEMTYPE aTreeItem,
@Nonnull final IHierarchyWalkerCallback aCallback)
{
walkSubTree (aTreeItem, new ChildrenProviderHasChildren (), aCallback);
}
public static > void walkSubTree (@Nonnull final ITEMTYPE aTreeItem,
@Nonnull final IChildrenProvider aChildrenProvider,
@Nonnull final IHierarchyWalkerCallback aCallback)
{
ValueEnforcer.notNull (aTreeItem, "TreeItem");
ValueEnforcer.notNull (aChildrenProvider, "ChildrenProvider");
ValueEnforcer.notNull (aCallback, "Callback");
aCallback.begin ();
try
{
if (aChildrenProvider.hasChildren (aTreeItem))
for (final ITEMTYPE aChildItem : aChildrenProvider.getChildren (aTreeItem))
_walkTree (aChildItem, aChildrenProvider, aCallback);
}
finally
{
aCallback.end ();
}
}
public static > void walkSubTreeData (@Nonnull final ITEMTYPE aTreeItem,
@Nonnull final IHierarchyWalkerCallback aDataCallback)
{
walkSubTreeData (aTreeItem, new ChildrenProviderHasChildren (), aDataCallback);
}
public static > void walkSubTreeData (@Nonnull final ITEMTYPE aTreeItem,
@Nonnull final IChildrenProvider aChildrenProvider,
@Nonnull final IHierarchyWalkerCallback aDataCallback)
{
ValueEnforcer.notNull (aDataCallback, "DataCallback");
// Wrap callback
walkSubTree (aTreeItem, aChildrenProvider, new DefaultHierarchyWalkerCallback ()
{
@Override
public void begin ()
{
aDataCallback.begin ();
}
@Override
public void onLevelDown ()
{
super.onLevelDown ();
aDataCallback.onLevelDown ();
}
@Override
public void onLevelUp ()
{
super.onLevelUp ();
aDataCallback.onLevelUp ();
}
@Override
public void end ()
{
aDataCallback.end ();
}
@Override
public void onItemBeforeChildren (@Nonnull final ITEMTYPE aItem)
{
aDataCallback.onItemBeforeChildren (aItem.getData ());
}
@Override
public void onItemAfterChildren (@Nonnull final ITEMTYPE aItem)
{
aDataCallback.onItemAfterChildren (aItem.getData ());
}
});
}
}
