ObjectProfileFilters.java

package com.vladium.utils;

// ----------------------------------------------------------------------------
/**
 * A Factory for a few stock node filters. See the implementation for details.
 * 
 * @author (C) <a href="http://www.javaworld.com/columns/jw-qna-index.shtml">Vlad Roubtsov</a>, 2003
 */
public
abstract class ObjectProfileFilters
{
    // public: ................................................................
    
    /**
     * Factory method for creating a visitor that only accepts profile nodes
     * with sizes larger than a given threshold value.
     * 
     * @param threshold node size in bytes
     */
    public static ObjectProfileNode.INodeFilter newSizeFilter (final int threshold)
    {
        return new SizeFilter (threshold);
    }
    
    /**
     * Factory method for creating a visitor that accepts a profile node only if
     * it is at least the k-th largest child of its parent for a given value
     * of k. E.g., newRankFilter(1) will prune the profile tree so that only the
     * largest child is visited for every node. 
     * 
     * @param rank acceptable size rank [must be >= 0]
     */
    public static ObjectProfileNode.INodeFilter newRankFilter (final int rank)
    {
        return new RankFilter (rank);
    }
    
    /**
     * Factory method for creating a visitor that accepts a profile node only if
     * its size is larger than a given threshold relative to the size of the root
     * node (i.e., size of the entire profile tree). 
     * 
     * @param threshold size fraction threshold
     */
    public static ObjectProfileNode.INodeFilter newSizeFractionFilter (final double threshold)
    {
        return new SizeFractionFilter (threshold);
    }

    /**
     * Factory method for creating a visitor that accepts a profile node only if
     * its size is larger than a given threshold relative to the size of its
     * parent node. This is useful for pruning the profile tree to show the
     * largest contributors at every tree level.
     * 
     * @param threshold size fraction threshold
     */    
    public static ObjectProfileNode.INodeFilter newParentSizeFractionFilter (final double threshold)
    {
        return new ParentSizeFractionFilter (threshold);
    }
    
    // protected: .............................................................

    // package: ...............................................................
    
    // private: ...............................................................
    
    
    private ObjectProfileFilters () {} // this class is not extendible


    private static final class SizeFilter implements IObjectProfileNode.INodeFilter
    {
        public boolean accept (final IObjectProfileNode node)
        {
            return node.size () >= m_threshold;
        }
        
        
        SizeFilter (final int threshold)
        {
            m_threshold = threshold;
        }
        
        
        private final int m_threshold;

    } // end of nested class
    
    
    private static final class RankFilter implements IObjectProfileNode.INodeFilter
    {
        public boolean accept (final IObjectProfileNode node)
        {
            final IObjectProfileNode parent = node.parent ();
            if (parent == null) return true;
            
            final IObjectProfileNode [] siblings = parent.children ();
            for (int r = 0, rLimit = Math.min (siblings.length, m_threshold); r< rLimit; ++ r)
                if (siblings [r] == node) return true;
            
            return false;
        }
        
        
        RankFilter (final int threshold)
        {
            m_threshold = threshold;
        }
        
        
        private final int m_threshold;

    } // end of nested class
    
    
    private static final class SizeFractionFilter implements IObjectProfileNode.INodeFilter
    {
        public boolean accept (final IObjectProfileNode node)
        {
            if (node.size () >= m_threshold * node.root ().size ())
                return true;
            else
                return false;
        }
        
        
        SizeFractionFilter (final double threshold)
        {
            m_threshold = threshold;
        }
        
        
        private final double m_threshold;

    } // end of nested class
    
    
    private static final class ParentSizeFractionFilter implements IObjectProfileNode.INodeFilter
    {
        public boolean accept (final IObjectProfileNode node)
        {
            final IObjectProfileNode parent = node.parent ();
            if (parent == null)
                return true; // always accept root node
            else if (node.size () >= m_threshold * parent.size ())
                return true;
            else
                return false;
        }
        
        
        ParentSizeFractionFilter (final double threshold)
        {
            m_threshold = threshold;
        }
        
        
        private final double m_threshold;

    } // end of nested class

} // end of class
// ----------------------------------------------------------------------------