diff --git a/demos/chartthemes/themewidget.cpp b/demos/chartthemes/themewidget.cpp
index 2ad217e..ea8c405 100644
--- a/demos/chartthemes/themewidget.cpp
+++ b/demos/chartthemes/themewidget.cpp
@@ -211,7 +211,7 @@ QChart* ThemeWidget::createBarChart(int valueCount) const
             QBarSet *set = new QBarSet("Set" + QString::number(i));
             foreach (Data data, m_dataTable[i])
                 *set << data.first.y();
-            series->addBarSet(set);
+            series->appendBarSet(set);
         }
         chart->addSeries(series);
     }
diff --git a/examples/barchart/main.cpp b/examples/barchart/main.cpp
index e29c805..b8711bc 100644
--- a/examples/barchart/main.cpp
+++ b/examples/barchart/main.cpp
@@ -69,11 +69,11 @@ int main(int argc, char *argv[])
 //![2]
 //![3]
     QBarSeries* series = new QBarSeries(categories);
-    series->addBarSet(set0);
-    series->addBarSet(set1);
-    series->addBarSet(set2);
-    series->addBarSet(set3);
-    series->addBarSet(set4);
+    series->appendBarSet(set0);
+    series->appendBarSet(set1);
+    series->appendBarSet(set2);
+    series->appendBarSet(set3);
+    series->appendBarSet(set4);
 //![3]
 //![4]
     QChart* chart = new QChart();
diff --git a/examples/percentbarchart/main.cpp b/examples/percentbarchart/main.cpp
index b32fce9..ab6b0e5 100644
--- a/examples/percentbarchart/main.cpp
+++ b/examples/percentbarchart/main.cpp
@@ -69,11 +69,11 @@ int main(int argc, char *argv[])
 //![2]
 //![3]
     QPercentBarSeries* series = new QPercentBarSeries(categories);
-    series->addBarSet(set0);
-    series->addBarSet(set1);
-    series->addBarSet(set2);
-    series->addBarSet(set3);
-    series->addBarSet(set4);
+    series->appendBarSet(set0);
+    series->appendBarSet(set1);
+    series->appendBarSet(set2);
+    series->appendBarSet(set3);
+    series->appendBarSet(set4);
 //![3]
 //![4]
     QChart* chart = new QChart();
diff --git a/examples/stackedbarchart/main.cpp b/examples/stackedbarchart/main.cpp
index dc1a037..842c205 100644
--- a/examples/stackedbarchart/main.cpp
+++ b/examples/stackedbarchart/main.cpp
@@ -69,11 +69,11 @@ int main(int argc, char *argv[])
 //![2]
 //![3]
     QStackedBarSeries* series = new QStackedBarSeries(categories);
-    series->addBarSet(set0);
-    series->addBarSet(set1);
-    series->addBarSet(set2);
-    series->addBarSet(set3);
-    series->addBarSet(set4);
+    series->appendBarSet(set0);
+    series->appendBarSet(set1);
+    series->appendBarSet(set2);
+    series->appendBarSet(set3);
+    series->appendBarSet(set4);
 //![3]
 //![4]
     QChart* chart = new QChart();
diff --git a/qmlplugin/declarativebarseries.cpp b/qmlplugin/declarativebarseries.cpp
index e0147ea..9143025 100644
--- a/qmlplugin/declarativebarseries.cpp
+++ b/qmlplugin/declarativebarseries.cpp
@@ -36,9 +36,9 @@ void DeclarativeBarSeries::componentComplete()
             *set1 << 5 << 0 << 0 << 4 << 0 << 7;
             *set2 << 3 << 5 << 8 << 13 << 8 << 5;
 
-            m_series->addBarSet(set0);
-            m_series->addBarSet(set1);
-            m_series->addBarSet(set2);
+            m_series->appendBarSet(set0);
+            m_series->appendBarSet(set1);
+            m_series->appendBarSet(set2);
 
             chart->addSeries(m_series);
         }
diff --git a/src/barchart/barchartitem.cpp b/src/barchart/barchartitem.cpp
index d259cd0..aea8727 100644
--- a/src/barchart/barchartitem.cpp
+++ b/src/barchart/barchartitem.cpp
@@ -140,9 +140,9 @@ QVector<QRectF> BarChartItem::calculateLayout()
             value->setPen(barSet->floatingValuePen());
 
             if (!qFuzzyIsNull(m_series->valueAt(set,category))) {
-                value->setValueString(QString::number(m_series->valueAt(set, category)));
+                value->setText(QString::number(m_series->valueAt(set, category)));
             } else {
-                value->setValueString(QString(""));
+                value->setText(QString(""));
             }
 
             itemIndex++;
diff --git a/src/barchart/barchartmodel.cpp b/src/barchart/barchartmodel.cpp
index c682092..8329f35 100644
--- a/src/barchart/barchartmodel.cpp
+++ b/src/barchart/barchartmodel.cpp
@@ -16,7 +16,7 @@ QStringList BarChartModel::category()
     return m_category;
 }
 
-void BarChartModel::addBarSet(QBarSet *set)
+void BarChartModel::appendBarSet(QBarSet *set)
 {
     m_dataModel.append(set);
 }
@@ -43,27 +43,27 @@ void BarChartModel::removeCategory(int i)
     m_category.removeAt(i);
 }
 
-QBarSet* BarChartModel::setAt(int index)
+QBarSet* BarChartModel::barsetAt(int index) const
 {
     return m_dataModel.at(index);
 }
 
-QList<QBarSet*> BarChartModel::barSets()
+QList<QBarSet*> BarChartModel::barSets() const
 {
     return m_dataModel;
 }
 
-int BarChartModel::barsetCount()
+int BarChartModel::barsetCount() const
 {
     return m_dataModel.count();
 }
 
-int BarChartModel::categoryCount()
+int BarChartModel::categoryCount() const
 {
     return m_category.count();
 }
 
-qreal BarChartModel::min()
+qreal BarChartModel::min() const
 {
     Q_ASSERT(m_dataModel.count() > 0);
     // TODO: make min and max members and update them when data changes.
@@ -81,7 +81,7 @@ qreal BarChartModel::min()
     return min;
 }
 
-qreal BarChartModel::max()
+qreal BarChartModel::max() const
 {
     Q_ASSERT(m_dataModel.count() > 0);
 
@@ -101,7 +101,7 @@ qreal BarChartModel::max()
     return max;
 }
 
-qreal BarChartModel::valueAt(int set, int category)
+qreal BarChartModel::valueAt(int set, int category) const
 {
     if ((set < 0) || (set >= m_dataModel.count())) {
         // No set, no value.
@@ -114,7 +114,7 @@ qreal BarChartModel::valueAt(int set, int category)
     return m_dataModel.at(set)->valueAt(category);
 }
 
-qreal BarChartModel::percentageAt(int set, int category)
+qreal BarChartModel::percentageAt(int set, int category) const
 {
     if ((set < 0) || (set >= m_dataModel.count())) {
         // No set, no value.
@@ -133,7 +133,7 @@ qreal BarChartModel::percentageAt(int set, int category)
 }
 
 
-qreal BarChartModel::categorySum(int category)
+qreal BarChartModel::categorySum(int category) const
 {
     qreal sum(0);
     int count = m_dataModel.count(); // Count sets
@@ -145,7 +145,7 @@ qreal BarChartModel::categorySum(int category)
     return sum;
 }
 
-qreal BarChartModel::maxCategorySum()
+qreal BarChartModel::maxCategorySum() const
 {
     qreal max = INT_MIN;
     int count = categoryCount();
diff --git a/src/barchart/barchartmodel_p.h b/src/barchart/barchartmodel_p.h
index 2427839..88f8d00 100644
--- a/src/barchart/barchartmodel_p.h
+++ b/src/barchart/barchartmodel_p.h
@@ -20,24 +20,24 @@ public:
     explicit BarChartModel(QStringList categories, QObject *parent = 0);
 
     QStringList category();
-    void addBarSet(QBarSet *set);
+    void appendBarSet(QBarSet *set);
     void removeBarSet(QBarSet *set);
     void insertBarSet(int i, QBarSet *set);
     void insertCategory(int i, QString category);
     void removeCategory(int i);
-    QBarSet *setAt(int index);
-    QList<QBarSet *> barSets();
+    QBarSet *barsetAt(int index) const;
+    QList<QBarSet *> barSets() const;
 
-    int barsetCount();          // Number of sets in model
-    int categoryCount();        // Number of categories
+    int barsetCount() const;          // Number of sets in model
+    int categoryCount() const;        // Number of categories
 
-    qreal max();                // Maximum value of all sets
-    qreal min();                // Minimum value of all sets
-    qreal valueAt(int set, int category);
-    qreal percentageAt(int set, int category);
+    qreal max() const;                // Maximum value of all sets
+    qreal min() const;                // Minimum value of all sets
+    qreal valueAt(int set, int category) const;
+    qreal percentageAt(int set, int category) const;
 
-    qreal categorySum(int category);
-    qreal maxCategorySum();     // returns maximum sum of sets in all categories.
+    qreal categorySum(int category) const;
+    qreal maxCategorySum() const;     // returns maximum sum of sets in all categories.
 
     QString categoryName(int category);
 
diff --git a/src/barchart/barvalue.cpp b/src/barchart/barvalue.cpp
index 23e6c21..859fbac 100644
--- a/src/barchart/barvalue.cpp
+++ b/src/barchart/barvalue.cpp
@@ -15,17 +15,17 @@ BarValue::BarValue(QBarSet &set, QGraphicsItem *parent)
     setVisible(false);
 }
 
-void BarValue::setValueString(QString str)
+void BarValue::setText(QString str)
 {
     m_valueString = str;
 }
 
-QString BarValue::valueString()
+QString BarValue::text() const
 {
     return m_valueString;
 }
 
-void BarValue::setPen(const QPen pen)
+void BarValue::setPen(const QPen &pen)
 {
     m_pen = pen;
 }
diff --git a/src/barchart/barvalue_p.h b/src/barchart/barvalue_p.h
index 172704d..eadacdd 100644
--- a/src/barchart/barvalue_p.h
+++ b/src/barchart/barvalue_p.h
@@ -17,10 +17,10 @@ class BarValue : public QGraphicsObject
 public:
     BarValue(QBarSet &set, QGraphicsItem *parent = 0);
 
-    void setValueString(QString str);
-    QString valueString();
+    void setText(QString str);
+    QString text() const;
 
-    void setPen(const QPen pen);
+    void setPen(const QPen &pen);
     QPen pen() const;
 
     void resize(qreal w, qreal h);
diff --git a/src/barchart/percentbarchartitem.cpp b/src/barchart/percentbarchartitem.cpp
index 90b0a64..c6f91c9 100644
--- a/src/barchart/percentbarchartitem.cpp
+++ b/src/barchart/percentbarchartitem.cpp
@@ -63,9 +63,9 @@ QVector<QRectF> PercentBarChartItem::calculateLayout()
                 QString vString(QString::number(p));
                 vString.truncate(3);
                 vString.append("%");
-                value->setValueString(vString);
+                value->setText(vString);
             } else {
-                value->setValueString(QString(""));
+                value->setText(QString(""));
             }
 
             itemIndex++;
diff --git a/src/barchart/qbarseries.cpp b/src/barchart/qbarseries.cpp
index d977987..6ed54da 100644
--- a/src/barchart/qbarseries.cpp
+++ b/src/barchart/qbarseries.cpp
@@ -50,9 +50,9 @@ QBarSeries::QBarSeries(QBarCategories categories, QObject *parent) : QSeries(par
     Connects the clicked(QString) and rightClicked(QString) signals
     of \a set to this series
 */
-void QBarSeries::addBarSet(QBarSet *set)
+void QBarSeries::appendBarSet(QBarSet *set)
 {
-    m_internalModel->addBarSet(set);
+    m_internalModel->appendBarSet(set);
     connect(set, SIGNAL(clicked(QString)), this, SLOT(barsetClicked(QString)));
     connect(set, SIGNAL(rightClicked(QString)), this, SLOT(barsetRightClicked(QString)));
     connect(set, SIGNAL(valueChanged()), this, SLOT(barsetChanged()));
@@ -91,7 +91,7 @@ void QBarSeries::removeCategory(int i)
 /*!
     Returns number of sets in series.
 */
-int QBarSeries::barsetCount()
+int QBarSeries::barsetCount() const
 {
     //    if(m_model)
     //        return m_mapBarTop - m_mapBarBottom;
@@ -102,7 +102,7 @@ int QBarSeries::barsetCount()
 /*!
     Returns number of categories in series
 */
-int QBarSeries::categoryCount()
+int QBarSeries::categoryCount() const
 {
     return m_internalModel->categoryCount();
 }
@@ -110,7 +110,7 @@ int QBarSeries::categoryCount()
 /*!
     Returns a list of sets in series. Keeps ownership of sets.
  */
-QList<QBarSet*> QBarSeries::barSets()
+QList<QBarSet*> QBarSeries::barSets() const
 {
     return m_internalModel->barSets();
 }
@@ -120,7 +120,7 @@ QList<QBarSet*> QBarSeries::barSets()
 */
 QBarSet* QBarSeries::barsetAt(int index)
 {
-    return m_internalModel->setAt(index);
+    return m_internalModel->barsetAt(index);
 }
 
 /*!
@@ -141,12 +141,12 @@ void QBarSeries::setToolTipEnabled(bool enabled)
     // TODO: what if we add sets after call to this function? Those sets won't have tooltip enabled.
     if (enabled) {
         for (int i=0; i<m_internalModel->barsetCount(); i++) {
-            QBarSet *set = m_internalModel->setAt(i);
+            QBarSet *set = m_internalModel->barsetAt(i);
             connect(set, SIGNAL(showToolTip(QPoint,QString)), this, SIGNAL(showToolTip(QPoint,QString)));
         }
     } else {
         for (int i=0; i<m_internalModel->barsetCount(); i++) {
-            QBarSet *set = m_internalModel->setAt(i);
+            QBarSet *set = m_internalModel->barsetAt(i);
             disconnect(set, SIGNAL(showToolTip(QPoint,QString)), this, SIGNAL(showToolTip(QPoint,QString)));
         }
     }
@@ -297,7 +297,7 @@ void QBarSeries::setModelMapping(int categories, int bottomBoundry, int topBound
             QBarSet* barSet = new QBarSet(QString("Column: %1").arg(i + 1));
             for(int m = m_mapFirst; m < m_mapFirst + m_mapCount; m++)
                 *barSet << m_model->data(m_model->index(m, i), Qt::DisplayRole).toDouble();
-            addBarSet(barSet);
+            appendBarSet(barSet);
         }
     } else {
         QStringList categories;
@@ -309,7 +309,7 @@ void QBarSeries::setModelMapping(int categories, int bottomBoundry, int topBound
             QBarSet* barSet = new QBarSet(QString("Row: %1").arg(i + 1));
             for(int m = m_mapFirst; m < m_mapFirst + m_mapCount; m++)
                 *barSet << m_model->data(m_model->index(i, m), Qt::DisplayRole).toDouble();
-            addBarSet(barSet);
+            appendBarSet(barSet);
         }
     }
 }
diff --git a/src/barchart/qbarseries.h b/src/barchart/qbarseries.h
index a5aef6d..1570314 100644
--- a/src/barchart/qbarseries.h
+++ b/src/barchart/qbarseries.h
@@ -21,14 +21,14 @@ public:
 
     virtual QSeriesType type() const { return QSeries::SeriesTypeBar; }
 
-    void addBarSet(QBarSet *set);               // Takes ownership of set
+    void appendBarSet(QBarSet *set);               // Takes ownership of set
     void removeBarSet(QBarSet *set);            // Releases ownership, doesn't delete set
     void insertBarSet(int i, QBarSet *set);
     void insertCategory(int i, QString category);
     void removeCategory(int i);
-    int barsetCount();
-    int categoryCount();
-    QList<QBarSet*> barSets();
+    int barsetCount() const;
+    int categoryCount() const;
+    QList<QBarSet*> barSets() const;
     QBarCategories categories() const;
 
     bool setModel(QAbstractItemModel *model);
diff --git a/src/barchart/qbarset.cpp b/src/barchart/qbarset.cpp
index e3107aa..f64a6a7 100644
--- a/src/barchart/qbarset.cpp
+++ b/src/barchart/qbarset.cpp
@@ -71,7 +71,7 @@ void QBarSet::setName(QString name)
 /*!
     Returns name of the set.
 */
-QString QBarSet::name()
+QString QBarSet::name() const
 {
     return m_name;
 }
@@ -99,7 +99,7 @@ void QBarSet::removeValue(int i)
 /*!
     Returns count of values in set.
 */
-int QBarSet::count()
+int QBarSet::count() const
 {
     return m_values.count();
 }
@@ -107,7 +107,7 @@ int QBarSet::count()
 /*!
     Returns value of set indexed by \a index
 */
-qreal QBarSet::valueAt(int index)
+qreal QBarSet::valueAt(int index) const
 {
     return m_values.at(index);
 }
@@ -124,7 +124,7 @@ void QBarSet::setValue(int index, qreal value)
 /*!
     Returns total sum of all values in barset.
 */
-qreal QBarSet::total()
+qreal QBarSet::total() const
 {
     qreal total(0);
     for (int i=0; i < m_values.count(); i++) {
diff --git a/src/barchart/qbarset.h b/src/barchart/qbarset.h
index 80c2349..08d7f5c 100644
--- a/src/barchart/qbarset.h
+++ b/src/barchart/qbarset.h
@@ -14,16 +14,16 @@ public:
     QBarSet(QString name, QObject *parent = 0);
 
     void setName(QString name);
-    QString name();
+    QString name() const;
     QBarSet& operator << (const qreal &value);  // appends new value to set
     void insertValue(int i, qreal value);
     void removeValue(int i);
 
     // TODO: remove indices eventually. Use as internal?
-    int count();                                // count of values in set
-    qreal valueAt(int index);                   // for modifying individual values
+    int count() const;                          // count of values in set
+    qreal valueAt(int index) const;                   // for modifying individual values
     void setValue(int index, qreal value);      // setter for individual value
-    qreal total();                              // total values in the set
+    qreal total() const;                              // total values in the set
 
     // TODO:
     //qreal value(QString category);
diff --git a/src/barchart/stackedbarchartitem.cpp b/src/barchart/stackedbarchartitem.cpp
index da54207..3f262cd 100644
--- a/src/barchart/stackedbarchartitem.cpp
+++ b/src/barchart/stackedbarchartitem.cpp
@@ -65,9 +65,9 @@ QVector<QRectF> StackedBarChartItem::calculateLayout()
             value->setPen(barSet->floatingValuePen());
 
             if (!qFuzzyIsNull(m_series->valueAt(set, category))) {
-                value->setValueString(QString::number(m_series->valueAt(set,category)));
+                value->setText(QString::number(m_series->valueAt(set,category)));
             } else {
-                value->setValueString(QString(""));
+                value->setText(QString(""));
             }
 
             itemIndex++;