tmf/org.eclipse.tracecompass.tmf.core/src/org/eclipse/tracecompass/internal/tmf/core/synchronization/TmfConstantTransform.java

   1 /*******************************************************************************
   2  * Copyright (c) 2014 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Matthew Khouzam - Initial API and implementation
  11  *******************************************************************************/
  12
  13 package org.eclipse.tracecompass.internal.tmf.core.synchronization;
  14
  15 import org.eclipse.jdt.annotation.NonNull;
  16 import org.eclipse.tracecompass.tmf.core.synchronization.ITmfTimestampTransform;
  17 import org.eclipse.tracecompass.tmf.core.synchronization.TimestampTransformFactory;
  18 import org.eclipse.tracecompass.tmf.core.timestamp.ITmfTimestamp;
  19
  20 /**
  21  * Constant transform, just offset your timestamp with another.
  22  *
  23  * @author Matthew Khouzam
  24  */
  25 public class TmfConstantTransform implements ITmfTimestampTransformInvertible {
  26
  27     /**
  28      * Serial ID
  29      */
  30     private static final long serialVersionUID = 417299521984404532L;
  31     private final long fOffset;
  32
  33     /**
  34      * Default constructor
  35      */
  36     public TmfConstantTransform() {
  37         // we really should be using an identity transform here.
  38         fOffset = 0;
  39     }
  40
  41     /**
  42      * Constructor with offset
  43      *
  44      * @param offset
  45      *            The offset of the linear transform in nanoseconds
  46      */
  47     public TmfConstantTransform(long offset) {
  48         fOffset = offset;
  49     }
  50
  51     /**
  52      * Constructor with offset timestamp
  53      *
  54      * @param offset
  55      *            The offset of the linear transform
  56      */
  57     public TmfConstantTransform(@NonNull ITmfTimestamp offset) {
  58         this(offset.toNanos());
  59     }
  60
  61     @Override
  62     public ITmfTimestamp transform(ITmfTimestamp timestamp) {
  63         return timestamp.normalize(fOffset, ITmfTimestamp.NANOSECOND_SCALE);
  64     }
  65
  66     /**
  67      * {@inheritDoc}
  68      *
  69      * @param timestamp
  70      *            the timestamp in nanoseconds
  71      * @return the timestamp in nanoseconds
  72      */
  73     @Override
  74     public long transform(long timestamp) {
  75         return fOffset + timestamp;
  76     }
  77
  78     @Override
  79     public ITmfTimestampTransform composeWith(ITmfTimestampTransform composeWith) {
  80         if (composeWith.equals(TmfTimestampTransform.IDENTITY)) {
  81             /* If composing with identity, just return this */
  82             return this;
  83         } else if (composeWith instanceof TmfConstantTransform) {
  84             TmfConstantTransform tct = (TmfConstantTransform) composeWith;
  85             final long offset = fOffset + tct.fOffset;
  86             if (offset == 0) {
  87                 return TmfTimestampTransform.IDENTITY;
  88             }
  89             return new TmfConstantTransform(offset);
  90         } else if (composeWith instanceof TmfTimestampTransformLinear) {
  91             throw new UnsupportedOperationException("Cannot compose a constant and linear transform yet"); //$NON-NLS-1$
  92         } else {
  93             /*
  94              * We do not know what to do with this kind of transform, just
  95              * return this
  96              */
  97             return this;
  98         }
  99     }
 100
 101     @Override
 102     public String toString() {
 103         StringBuilder builder = new StringBuilder();
 104         builder.append("TmfConstantTransform [ offset = "); //$NON-NLS-1$
 105         builder.append(fOffset);
 106         builder.append(" ]"); //$NON-NLS-1$
 107         return builder.toString();
 108     }
 109
 110     @Override
 111     public ITmfTimestampTransform inverse() {
 112         return TimestampTransformFactory.createWithOffset(-1 * fOffset);
 113     }
 114
 115 }