package org.apache.maven.shared.dependency.tree.traversal;
/*
* 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.
*/
import java.io.PrintWriter;
import java.io.Writer;
import java.util.List;
import org.apache.maven.shared.dependency.tree.DependencyNode;
/**
* A dependency node visitor that serializes visited nodes to a writer.
*
* @author <a href="mailto:markhobson@gmail.com">Mark Hobson</a>
* @version $Id: SerializingDependencyNodeVisitor.java 1595642 2014-05-18 17:32:08Z jvanzyl $
* @since 1.1
*/
public class SerializingDependencyNodeVisitor
implements DependencyNodeVisitor
{
// classes ----------------------------------------------------------------
/**
* Provides tokens to use when serializing the dependency tree.
*/
public static class TreeTokens
{
private final String nodeIndent;
private final String lastNodeIndent;
private final String fillIndent;
private final String lastFillIndent;
public TreeTokens( String nodeIndent, String lastNodeIndent, String fillIndent, String lastFillIndent )
{
this.nodeIndent = nodeIndent;
this.lastNodeIndent = lastNodeIndent;
this.fillIndent = fillIndent;
this.lastFillIndent = lastFillIndent;
}
public String getNodeIndent( boolean last )
{
return last ? lastNodeIndent : nodeIndent;
}
public String getFillIndent( boolean last )
{
return last ? lastFillIndent : fillIndent;
}
}
// constants --------------------------------------------------------------
/**
* Whitespace tokens to use when outputing the dependency tree.
*/
public static final TreeTokens WHITESPACE_TOKENS = new TreeTokens( " ", " ", " ", " " );
/**
* The standard ASCII tokens to use when outputing the dependency tree.
*/
public static final TreeTokens STANDARD_TOKENS = new TreeTokens( "+- ", "\\- ", "| ", " " );
/**
* The extended ASCII tokens to use when outputing the dependency tree.
*/
public static final TreeTokens EXTENDED_TOKENS = new TreeTokens( "\u00c3\u00c4 ", "\u00c0\u00c4 ", "\u00b3 ",
" " );
// fields -----------------------------------------------------------------
/**
* The writer to serialize to.
*/
private final PrintWriter writer;
/**
* The tokens to use when serializing the dependency tree.
*/
private final TreeTokens tokens;
/**
* The depth of the currently visited dependency node.
*/
private int depth;
// constructors -----------------------------------------------------------
/**
* Creates a dependency node visitor that serializes visited nodes to the specified writer using whitespace tokens.
*
* @param writer the writer to serialize to
*/
public SerializingDependencyNodeVisitor( Writer writer )
{
this( writer, WHITESPACE_TOKENS );
}
/**
* Creates a dependency node visitor that serializes visited nodes to the specified writer using the specified
* tokens.
*
* @param writer the writer to serialize to
* @param tokens the tokens to use when serializing the dependency tree
*/
public SerializingDependencyNodeVisitor( Writer writer, TreeTokens tokens )
{
if ( writer instanceof PrintWriter )
{
this.writer = (PrintWriter) writer;
}
else
{
this.writer = new PrintWriter( writer, true );
}
this.tokens = tokens;
depth = 0;
}
// DependencyNodeVisitor methods ------------------------------------------
/**
* {@inheritDoc}
*/
public boolean visit( DependencyNode node )
{
indent( node );
writer.println( node.toNodeString() );
depth++;
return true;
}
/**
* {@inheritDoc}
*/
public boolean endVisit( DependencyNode node )
{
depth--;
return true;
}
// private methods --------------------------------------------------------
/**
* Writes the necessary tokens to indent the specified dependency node to this visitor's writer.
*
* @param node the dependency node to indent
*/
private void indent( DependencyNode node )
{
for ( int i = 1; i < depth; i++ )
{
writer.write( tokens.getFillIndent( isLast( node, i ) ) );
}
if ( depth > 0 )
{
writer.write( tokens.getNodeIndent( isLast( node ) ) );
}
}
/**
* Gets whether the specified dependency node is the last of its siblings.
*
* @param node the dependency node to check
* @return <code>true</code> if the specified dependency node is the last of its last siblings
*/
private boolean isLast( DependencyNode node )
{
// TODO: remove node argument and calculate from visitor calls only
DependencyNode parent = node.getParent();
boolean last;
if ( parent == null )
{
last = true;
}
else
{
List<DependencyNode> siblings = parent.getChildren();
last = ( siblings.indexOf( node ) == siblings.size() - 1 );
}
return last;
}
/**
* Gets whether the specified dependency node ancestor is the last of its siblings.
*
* @param node the dependency node whose ancestor to check
* @param ancestorDepth the depth of the ancestor of the specified dependency node to check
* @return <code>true</code> if the specified dependency node ancestor is the last of its siblings
*/
private boolean isLast( DependencyNode node, int ancestorDepth )
{
// TODO: remove node argument and calculate from visitor calls only
int distance = depth - ancestorDepth;
while ( distance-- > 0 )
{
node = node.getParent();
}
return isLast( node );
}
}