Package org.eclipse.mat.snapshot

Class Histogram

java.lang.Object
org.eclipse.mat.snapshot.HistogramRecord
org.eclipse.mat.snapshot.Histogram
All Implemented Interfaces:
Serializable, IIconProvider, IResult, IResultTable, IStructuredResult
public class Histogram extends HistogramRecord implements IResultTable, IIconProvider
Class histogram - heap objects aggregated by their class. It holds the number and consumed memory of the objects aggregated per class and aggregated per class loader.
See Also:

  • Constructor Details

    • Histogram

      public Histogram(String label, ArrayList<ClassHistogramRecord> classHistogramRecords, ArrayList<ClassLoaderHistogramRecord> classLoaderHistogramRecords, long numberOfObjects, long usedHeapSize, long retainedHeapSize)
      Construct a histogram
      Parameters:
      label - the name of the whole histogram
      classHistogramRecords - the classes
      classLoaderHistogramRecords - the class loaders
      numberOfObjects - the total number of objects
      usedHeapSize - the shallow size of all the objects
      retainedHeapSize - the retained size of all the objects, or 0 if unknown

    • Histogram

      public Histogram(String label, ArrayList<ClassHistogramRecord> classHistogramRecords, ArrayList<ClassLoaderHistogramRecord> classLoaderHistogramRecords, long numberOfObjects, long usedHeapSize, long retainedHeapSize, boolean isDefaultHistogram)
      Construct a histogram
      Parameters:
      label - the name of the whole histogram
      classHistogramRecords - the classes
      classLoaderHistogramRecords - the class loaders
      numberOfObjects - the total number of objects
      usedHeapSize - the shallow size of all the objects
      retainedHeapSize - the retained size of all the objects, or 0 if unknown
      isDefaultHistogram - a histogram of the whole snapshot

  • Method Details

    • getClassHistogramRecords

      public Collection<ClassHistogramRecord> getClassHistogramRecords()
      Get collection of all the classes for all the objects which were found in the set of objects on which the class histogram was computed.
      Returns:
      collection of all the classes for all the objects which were found in the set of objects on which the class histogram was computed

    • getClassLoaderHistogramRecords

      public Collection<ClassLoaderHistogramRecord> getClassLoaderHistogramRecords()
      Get collection of all the class loaders for all the classes for all the objects which were found in the set of objects on which the class histogram was computed.
      Returns:
      collection of all the class loaders for all the classes for all the objects which were found in the set of objects on which the class histogram was computed

    • diffWithBaseline

      public Histogram diffWithBaseline(Histogram baseline)
      Compute a new histogram as difference of this histogram compared to (minus) the given baseline histogram.

      This method can be used to check what has changed from one histogram to another, to compute a delta.

      Parameters:
      baseline - baseline histogram
      Returns:
      difference histogram between this histogram compared to (minus) the given baseline histogram

    • intersectWithAnother

      public Histogram intersectWithAnother(Histogram another)
      Compute a new histogram as intersection of this histogram compared to (equals) the given another histogram.

      This method can be used to check what remains the same within two histograms, e.g. if you have two histograms it shows what hasn't changed, e.g. if you have two difference histograms it shows what remained the same change (increase or decrease; used in gradient memory leak analysis).

      Note: Heap space is not taken into account in this analysis, only the number of objects, i.e. when the number of objects is the same, you will see this number of objects, otherwise or if there are no objects of a particular class you won't get a histogram record for it!

      Parameters:
      another - another histogram
      Returns:
      intersection histogram of this histogram compared to (equals) the given another histogram

    • isDefaultHistogram

      public boolean isDefaultHistogram()

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • generateClassHistogramRecordTextReport

      public static String generateClassHistogramRecordTextReport(Histogram histogram, Comparator<HistogramRecord> comparator)
      Generate human readable text based report from a histogram.
      Parameters:
      histogram - histogram you want a human reable text based report for
      comparator - comparator to be used for sorting the histogram records ( HistogramRecord provides some default comparators)
      Returns:
      human redable text based report for the given histogram

    • generateClassHistogramRecordCsvReport

      public static String generateClassHistogramRecordCsvReport(Histogram histogram, Comparator<HistogramRecord> comparator)
      Generate machine/human readable comma separated report from an histogram.
      Parameters:
      histogram - histogram you want a machine/human readable comma separated report for
      comparator - comparator to be used for sorting the histogram records ( HistogramRecord provides some default comparators)
      Returns:
      machine/human readable comma separated report for the given histogram

    • generateClassLoaderHistogramRecordCsvReport

      public static String generateClassLoaderHistogramRecordCsvReport(Histogram histogram, Comparator<HistogramRecord> comparator)
      Generate machine/human readable comma separated report from an histogram.
      Parameters:
      histogram - histogram you want a machine/human readable comma separated report for
      comparator - comparator to be used for sorting the histogram records ( HistogramRecord provides some default comparators)
      Returns:
      machine/human readable comma separated report for the given histogram

    • getResultMetaData

      public ResultMetaData getResultMetaData()
      Description copied from interface: IResult
      (Optionally) Return meta data of the result needed to fine-tune the display of the result. This could include an additional context, an additional query to run on selected data from the result , additional calculated columns, or an indication that the results are already presorted.
      Specified by:
      getResultMetaData in interface IResult
      Returns:
      the metadata for the result, used to obtain extra data

    • getColumns

      public Column[] getColumns()
      Description copied from interface: IStructuredResult
      The columns of the tree or table.
      Specified by:
      getColumns in interface IStructuredResult
      Returns:
      an array of all the columns

    • getRowCount

      public int getRowCount()
      Description copied from interface: IResultTable
      Returns the number of rows in the result table.
      Specified by:
      getRowCount in interface IResultTable
      Returns:
      the number of rows

    • getRow

      public Object getRow(int rowId)
      Description copied from interface: IResultTable
      Returns the object of the row with the given row number.
      Specified by:
      getRow in interface IResultTable
      Parameters:
      rowId - The row number.
      Returns:
      an opaque row object representing this row which can be passed to IStructuredResult.getContext(Object) or IStructuredResult.getColumnValue(Object, int).

    • getColumnValue

      public Object getColumnValue(Object row, int columnIndex)
      Description copied from interface: IStructuredResult
      Returns the (unformatted) value of a table/tree cell.
      Specified by:
      getColumnValue in interface IStructuredResult
      Parameters:
      row - The row object as returned by the IResultTable.getRow(int) or IResultTree.getElements() or IResultTree.getChildren(Object) methods
      columnIndex - The index of the column.
      Returns:
      the cell value

    • getContext

      public IContextObject getContext(Object row)
      Description copied from interface: IStructuredResult
      The default context of the row which is used to display information in the object inspector. Unless no context provider is given via the ResultMetaData, it is also used for the context menu on a row.
      Specified by:
      getContext in interface IStructuredResult
      Parameters:
      row - The row object as returned by the IResultTable.getRow(int) or IResultTree.getElements() or IResultTree.getChildren(Object) methods.
      Returns:
      a context object holding details about that row

    • getIcon

      public URL getIcon(Object row)
      Specified by:
      getIcon in interface IIconProvider

    • groupByClassLoader

      public IResultTree groupByClassLoader()
      implementation as result tree grouped by class loader

    • groupByPackage

      public IResultTree groupByPackage()
      implementation as result tree grouped by package

    • groupBySuperclass

      public IResultTree groupBySuperclass(ISnapshot snapshot)
      implementation as result tree grouped by superclass
      Since:
      1.0