Calculator editor

calculatorpp-core/src/main/java/org/solovyev/android/calculator/Calculator.java

@@ -27,4 +27,8 @@ public interface Calculator extends CalculatorEventContainer {
 
     @NotNull
     CalculatorEventDataId convert(@NotNull Generic generic, @NotNull NumeralBase to);
+
+    @NotNull
+    CalculatorEventDataId fireCalculatorEvent(@NotNull CalculatorEventType calculatorEventType, @Nullable Object data);
+
 }

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEditor.java

@@ -16,4 +16,58 @@ public interface CalculatorEditor extends CalculatorEventListener/*, CursorContr
     CalculatorEditorViewState getViewState();
 
     void setViewState(@NotNull CalculatorEditorViewState viewState);
+
+    /*
+    **********************************************************************
+    *
+    *                           CURSOR CONTROL
+    *
+    **********************************************************************
+    */
+    /**
+     * Method sets the cursor to the beginning
+     */
+    @NotNull
+    public CalculatorEditorViewState setCursorOnStart();
+
+    /**
+     * Method sets the cursor to the end
+     */
+    @NotNull
+    public CalculatorEditorViewState setCursorOnEnd();
+
+    /**
+     * Method moves cursor to the left of current position
+     */
+    @NotNull
+    public CalculatorEditorViewState moveCursorLeft();
+
+    /**
+     * Method moves cursor to the right of current position
+     */
+    @NotNull
+    public CalculatorEditorViewState moveCursorRight();
+
+
+    /*
+    **********************************************************************
+    *
+    *                           EDITOR OPERATIONS
+    *
+    **********************************************************************
+    */
+    @NotNull
+    CalculatorEditorViewState erase();
+
+    @NotNull
+    CalculatorEditorViewState setText(@NotNull String text);
+
+    @NotNull
+    CalculatorEditorViewState setText(@NotNull String text, int selection);
+
+    @NotNull
+    CalculatorEditorViewState insert(@NotNull String text);
+
+    @NotNull
+    CalculatorEditorViewState moveSelection(int offset);
 }

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEditorChangeEventData.java

@@ -0,0 +1,17 @@
+package org.solovyev.android.calculator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: Solovyev_S
+ * Date: 21.09.12
+ * Time: 13:46
+ */
+public interface CalculatorEditorChangeEventData {
+
+    @NotNull
+    CalculatorEditorViewState getOldState();
+
+    @NotNull
+    CalculatorEditorViewState getNewState();
+}

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEditorChangeEventDataImpl.java

@@ -0,0 +1,34 @@
+package org.solovyev.android.calculator;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: Solovyev_S
+ * Date: 21.09.12
+ * Time: 13:46
+ */
+public class CalculatorEditorChangeEventDataImpl implements CalculatorEditorChangeEventData {
+
+    @NotNull
+    private CalculatorEditorViewState oldState;
+
+    @NotNull
+    private CalculatorEditorViewState newState;
+
+    public CalculatorEditorChangeEventDataImpl(@NotNull CalculatorEditorViewState oldState, @NotNull CalculatorEditorViewState newState) {
+        this.oldState = oldState;
+        this.newState = newState;
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState getOldState() {
+        return this.oldState;
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState getNewState() {
+        return this.newState;
+    }
+}

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEditorImpl.java

@@ -19,6 +19,13 @@ public class CalculatorEditorImpl implements CalculatorEditor {
     @NotNull
     private CalculatorEditorViewState lastViewState = CalculatorEditorViewStateImpl.newDefaultInstance();
 
+    @NotNull
+    private final Calculator calculator;
+
+    public CalculatorEditorImpl(@NotNull Calculator calculator) {
+        this.calculator = calculator;
+    }
+
     @Override
     public void setView(@Nullable CalculatorEditorView view) {
         synchronized (viewLock) {
@@ -37,12 +44,16 @@ public class CalculatorEditorImpl implements CalculatorEditor {
     }
 
     @Override
-    public void setViewState(@NotNull CalculatorEditorViewState viewState) {
+    public void setViewState(@NotNull CalculatorEditorViewState newViewState) {
         synchronized (viewLock) {
-            this.lastViewState = viewState;
+            final CalculatorEditorViewState oldViewState = this.lastViewState;
+
+            this.lastViewState = newViewState;
             if (this.view != null) {
-                this.view.setState(viewState);
+                this.view.setState(newViewState);
             }
+
+            calculator.fireCalculatorEvent(CalculatorEventType.editor_state_changed, new CalculatorEditorChangeEventDataImpl(oldViewState, newViewState));
         }
     }
 
@@ -53,35 +64,130 @@ public class CalculatorEditorImpl implements CalculatorEditor {
         //To change body of implemented methods use File | Settings | File Templates.
     }
 
-    public void setCursorOnStart() {
+    @NotNull
+    public CalculatorEditorViewState setCursorOnStart() {
         synchronized (viewLock) {
-            newSelectionViewState(0);
+            return newSelectionViewState(0);
         }
     }
 
-    private void newSelectionViewState(int newSelection) {
+    @NotNull
-        setViewState(CalculatorEditorViewStateImpl.newSelection(this.lastViewState, newSelection));
+    private CalculatorEditorViewState newSelectionViewState(int newSelection) {
-    }
+        if (this.lastViewState.getSelection() != newSelection) {
-
+            final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newSelection(this.lastViewState, newSelection);
-    public void setCursorOnEnd() {
+            setViewState(result);
-        synchronized (viewLock) {
+            return result;
-            newSelectionViewState(this.lastViewState.getText().length());
+        } else {
+            return this.lastViewState;
         }
     }
 
-    public void moveCursorLeft() {
+    @NotNull
+    public CalculatorEditorViewState setCursorOnEnd() {
+        synchronized (viewLock) {
+            return newSelectionViewState(this.lastViewState.getText().length());
+        }
+    }
+
+    @NotNull
+    public CalculatorEditorViewState moveCursorLeft() {
         synchronized (viewLock) {
             if (this.lastViewState.getSelection() > 0) {
-                newSelectionViewState(this.lastViewState.getSelection() - 1);
+                return newSelectionViewState(this.lastViewState.getSelection() - 1);
+            } else {
+                return this.lastViewState;
             }
         }
     }
 
-    public void moveCursorRight() {
+    @NotNull
+    public CalculatorEditorViewState moveCursorRight() {
         synchronized (viewLock) {
             if (this.lastViewState.getSelection() < this.lastViewState.getText().length()) {
-                newSelectionViewState(this.lastViewState.getSelection() + 1);
+                return newSelectionViewState(this.lastViewState.getSelection() + 1);
+            } else {
+                return this.lastViewState;
             }
         }
     }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState erase() {
+        synchronized (viewLock) {
+            int selection = this.lastViewState.getSelection();
+            final String text = this.lastViewState.getText();
+            if (selection > 0 && text.length() > 0 && selection <= text.length()) {
+                final StringBuilder newText = new StringBuilder(text.length() - 1);
+                newText.append(text.substring(0, selection - 1)).append(text.substring(selection, text.length()));
+
+                final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newInstance(newText.toString(), selection - 1);
+                setViewState(result);
+                return result;
+            } else {
+                return this.lastViewState;
+            }
+        }
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState setText(@NotNull String text) {
+        synchronized (viewLock) {
+            final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newInstance(text, text.length());
+            setViewState(result);
+            return result;
+        }
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState setText(@NotNull String text, int selection) {
+        synchronized (viewLock) {
+            selection = correctSelection(selection, text);
+
+            final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newInstance(text, selection);
+            setViewState(result);
+            return result;
+        }
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState insert(@NotNull String text) {
+        synchronized (viewLock) {
+            final int selection = this.lastViewState.getSelection();
+            final String oldText = this.lastViewState.getText();
+
+            final StringBuilder newText = new StringBuilder(text.length() + oldText.length());
+
+            newText.append(oldText.substring(0, selection));
+            newText.append(text);
+            newText.append(oldText.substring(selection));
+
+            final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newInstance(newText.toString(), text.length() + selection);
+            setViewState(result);
+            return result;
+        }
+    }
+
+    @NotNull
+    @Override
+    public CalculatorEditorViewState moveSelection(int offset) {
+        synchronized (viewLock) {
+            int selection = this.lastViewState.getSelection() + offset;
+
+            selection = correctSelection(selection, this.lastViewState.getText());
+
+            final CalculatorEditorViewState result = CalculatorEditorViewStateImpl.newSelection(this.lastViewState, selection);
+            setViewState(result);
+            return result;
+        }
+    }
+
+    private int correctSelection(int selection, @NotNull String text) {
+        int result = Math.max(selection, 0);
+        result = Math.min(result, text.length());
+        return result;
+    }
 }

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEditorViewStateImpl.java

@@ -46,4 +46,12 @@ public class CalculatorEditorViewStateImpl implements CalculatorEditorViewState
 
         return result;
     }
+
+    @NotNull
+    public static CalculatorEditorViewState newInstance(@NotNull String text, int selection) {
+        final CalculatorEditorViewStateImpl result = new CalculatorEditorViewStateImpl();
+        result.text = text;
+        result.selection = selection;
+        return result;
+    }
 }

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorEventType.java

@@ -40,7 +40,18 @@ public enum CalculatorEventType {
     conversion_started,
 
     // @NotNull String conversion result
-    conversion_finished;
+    conversion_finished,
+
+    /*
+    **********************************************************************
+    *
+    *                           EDITOR
+    *
+    **********************************************************************
+    */
+
+    // @NotNull org.solovyev.android.calculator.CalculatorEditorChangeEventData
+    editor_state_changed;
 
     public boolean isOfType(@NotNull CalculatorEventType... types) {
         for (CalculatorEventType type : types) {

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java

@@ -26,7 +26,7 @@ import java.util.concurrent.atomic.AtomicLong;
  * Date: 20.09.12
  * Time: 16:42
  */
-public class CalculatorImpl implements Calculator {
+public class CalculatorImpl implements Calculator, CalculatorEventListener {
 
     private static final long FIRST_ID = 0;
 
@@ -46,6 +46,7 @@ public class CalculatorImpl implements Calculator {
     private final Executor threadPoolExecutor = Executors.newFixedThreadPool(10);
 
     public CalculatorImpl() {
+        this.addCalculatorEventListener(this);
     }
 
     @NotNull
@@ -161,6 +162,21 @@ public class CalculatorImpl implements Calculator {
         return eventDataId;
     }
 
+    @NotNull
+    @Override
+    public CalculatorEventDataId fireCalculatorEvent(@NotNull final CalculatorEventType calculatorEventType, @Nullable final Object data) {
+        final CalculatorEventDataId eventDataId = nextCalculatorEventDataId();
+
+        threadPoolExecutor.execute(new Runnable() {
+            @Override
+            public void run() {
+                fireCalculatorEvent(CalculatorEventDataImpl.newInstance(eventDataId), calculatorEventType, data);
+            }
+        });
+
+        return eventDataId;
+    }
+
     @NotNull
     private CalculatorEventData newConversionEventData(@NotNull Long sequenceId) {
         return CalculatorEventDataImpl.newInstance(nextEventDataId(sequenceId));
@@ -280,6 +296,15 @@ public class CalculatorImpl implements Calculator {
         calculatorEventContainer.fireCalculatorEvents(calculatorEvents);
     }
 
+    @Override
+    public void onCalculatorEvent(@NotNull CalculatorEventData calculatorEventData, @NotNull CalculatorEventType calculatorEventType, @Nullable Object data) {
+        if ( calculatorEventType == CalculatorEventType.editor_state_changed ) {
+            final CalculatorEditorChangeEventData changeEventData = (CalculatorEditorChangeEventData) data;
+
+            evaluate(JsclOperation.numeric, changeEventData.getNewState().getText());
+        }
+    }
+
     public static final class ConversionException extends Exception {
         private ConversionException() {
         }

calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorLocatorImpl.java

@@ -16,10 +16,10 @@ public class CalculatorLocatorImpl implements CalculatorLocator {
     private final CalculatorDisplay calculatorDisplay = new CalculatorDisplayImpl();
 
     @NotNull
-    private final CalculatorEditor calculatorEditor = new CalculatorEditorImpl();
+    private final Calculator calculator = new CalculatorImpl();
 
     @NotNull
-    private final Calculator calculator = new CalculatorImpl();
+    private final CalculatorEditor calculatorEditor = new CalculatorEditorImpl(calculator);
 
     @NotNull
     private static final CalculatorLocator instance = new CalculatorLocatorImpl();

calculatorpp-core/src/main/java/org/solovyev/android/calculator/ToJsclTextProcessor.java

@@ -8,12 +8,7 @@ package org.solovyev.android.calculator;
 
 import jscl.math.function.IConstant;
 import org.jetbrains.annotations.NotNull;
-import org.solovyev.android.calculator.CalculatorApplication;
-import org.solovyev.android.calculator.CalculatorParseException;
-import org.solovyev.android.calculator.PreparedExpression;
-import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.text.TextProcessor;
-import org.solovyev.android.msg.AndroidMessage;
 import org.solovyev.common.StartsWithFinder;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.common.collections.CollectionsUtils;
@@ -57,7 +52,7 @@ public class ToJsclTextProcessor implements TextProcessor<PreparedExpression, St
 		MathType.Result mathTypeResult = null;
 		MathType.Result mathTypeBefore;
 
-		final LiteNumberBuilder nb = new LiteNumberBuilder(CalculatorEngine.instance.getEngine());
+		final LiteNumberBuilder nb = new LiteNumberBuilder(CalculatorLocatorImpl.getInstance().getCalculatorEngine().getEngine());
 		for (int i = 0; i < s.length(); i++) {
 			if (s.charAt(i) == ' ') continue;
 			startsWithFinder.setI(i);
@@ -80,8 +75,7 @@ public class ToJsclTextProcessor implements TextProcessor<PreparedExpression, St
 			if (mathTypeBefore != null &&
 					(mathTypeBefore.getMathType() == MathType.function || mathTypeBefore.getMathType() == MathType.operator) &&
 						CollectionsUtils.find(MathType.openGroupSymbols, startsWithFinder) != null) {
-                final AndroidMessage androidMessage = new AndroidMessage(R.string.msg_5, MessageType.error, CalculatorApplication.getInstance(), mathTypeBefore.getMatch());
+                throw new CalculatorParseException(i, s, new CalculatorMessage(CalculatorMessages.msg_005, MessageType.error, mathTypeBefore.getMatch()));
-                throw new CalculatorParseException(i, s, androidMessage);
 			}
 
 			i = mathTypeResult.processToJscl(result, i);
@@ -92,8 +86,7 @@ public class ToJsclTextProcessor implements TextProcessor<PreparedExpression, St
 	@NotNull
 	private static PreparedExpression replaceVariables(@NotNull final String s, int depth, @NotNull List<IConstant> undefinedVars) throws CalculatorParseException {
 		if (depth >= MAX_DEPTH) {
-            final AndroidMessage androidMessage = new AndroidMessage(R.string.msg_6, MessageType.error, CalculatorApplication.getInstance());
+            throw new CalculatorParseException(s, new CalculatorMessage(CalculatorMessages.msg_006, MessageType.error));
-            throw new CalculatorParseException(s, androidMessage);
 		} else {
 			depth++;
 		}
@@ -109,9 +102,9 @@ public class ToJsclTextProcessor implements TextProcessor<PreparedExpression, St
 			if (functionName == null) {
 				String operatorName = CollectionsUtils.find(MathType.operator.getTokens(), startsWithFinder);
 				if (operatorName == null) {
-					String varName = CollectionsUtils.find(CalculatorEngine.instance.getVarsRegistry().getNames(), startsWithFinder);
+					String varName = CollectionsUtils.find(CalculatorLocatorImpl.getInstance().getCalculatorEngine().getVarsRegistry().getNames(), startsWithFinder);
 					if (varName != null) {
-						final IConstant var = CalculatorEngine.instance.getVarsRegistry().get(varName);
+						final IConstant var = CalculatorLocatorImpl.getInstance().getCalculatorEngine().getVarsRegistry().get(varName);
 						if (var != null) {
 							if (!var.isDefined()) {
 								undefinedVars.add(var);

calculatorpp-core/src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryImpl.java

@@ -140,6 +140,7 @@ public class CalculatorHistoryImpl implements CalculatorHistory {
         if (calculatorEventType.isOfType(CalculatorEventType.calculation_started, CalculatorEventType.calculation_result, CalculatorEventType.calculation_failed)) {
 
             if ( calculatorEventData.isAfter(this.lastEventDataId) ) {
+/*
 
                 switch (calculatorEventType) {
                     case calculation_started:
@@ -149,6 +150,7 @@ public class CalculatorHistoryImpl implements CalculatorHistory {
 
                 CalculatorLocatorImpl.getInstance().getCalculatorDisplay().get
                 CalculatorHistoryState.newInstance(new TextViewEditorAdapter(this.editor), display);
+*/
 
                 this.lastEventDataId = calculatorEventData;
             }

calculatorpp-core/src/test/java/org/solovyev/android/calculator/CalculatorEditorImplTest.java

@@ -0,0 +1,200 @@
+package org.solovyev.android.calculator;
+
+import junit.framework.Assert;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * User: Solovyev_S
+ * Date: 21.09.12
+ * Time: 12:44
+ */
+public class CalculatorEditorImplTest {
+
+    @NotNull
+    private CalculatorEditor calculatorEditor;
+
+    @Before
+    public void setUp() throws Exception {
+        this.calculatorEditor = new CalculatorEditorImpl(new CalculatorImpl());
+    }
+
+    @Test
+    public void testInsert() throws Exception {
+        CalculatorEditorViewState viewState = this.calculatorEditor.getViewState();
+
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.insert("");
+
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.insert("test");
+
+        Assert.assertEquals("test", viewState.getText());
+        Assert.assertEquals(4, viewState.getSelection());
+
+        viewState = this.calculatorEditor.insert("test");
+        Assert.assertEquals("testtest", viewState.getText());
+        Assert.assertEquals(8, viewState.getSelection());
+
+        viewState = this.calculatorEditor.insert("");
+        Assert.assertEquals("testtest", viewState.getText());
+        Assert.assertEquals(8, viewState.getSelection());
+
+        viewState = this.calculatorEditor.insert("1234567890");
+        Assert.assertEquals("testtest1234567890", viewState.getText());
+        Assert.assertEquals(18, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveCursorLeft();
+        viewState = this.calculatorEditor.insert("9");
+        Assert.assertEquals("testtest12345678990", viewState.getText());
+        Assert.assertEquals(18, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setCursorOnStart();
+        viewState = this.calculatorEditor.insert("9");
+        Assert.assertEquals("9testtest12345678990", viewState.getText());
+        Assert.assertEquals(1, viewState.getSelection());
+
+        viewState = this.calculatorEditor.erase();
+        viewState = this.calculatorEditor.insert("9");
+        Assert.assertEquals("9testtest12345678990", viewState.getText());
+        Assert.assertEquals(1, viewState.getSelection());
+    }
+
+    @Test
+    public void testErase() throws Exception {
+        this.calculatorEditor.setText("");
+        this.calculatorEditor.erase();
+
+        Assert.assertEquals("", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.setText("test");
+        this.calculatorEditor.erase();
+        Assert.assertEquals("tes", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("te", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("t", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.setText("1234");
+        this.calculatorEditor.moveCursorLeft();
+        this.calculatorEditor.erase();
+        Assert.assertEquals("124", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("14", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.erase();
+        Assert.assertEquals("4", this.calculatorEditor.getViewState().getText());
+
+        this.calculatorEditor.setText("1");
+        this.calculatorEditor.moveCursorLeft();
+        this.calculatorEditor.erase();
+        Assert.assertEquals("1", this.calculatorEditor.getViewState().getText());
+    }
+
+    @Test
+    public void testMoveSelection() throws Exception {
+        this.calculatorEditor.setText("");
+
+        CalculatorEditorViewState viewState = this.calculatorEditor.moveSelection(0);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(2);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(100);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-3);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-100);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState =  this.calculatorEditor.setText("0123456789");
+
+        viewState = this.calculatorEditor.moveSelection(0);
+        Assert.assertEquals(10, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(1);
+        Assert.assertEquals(10, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-2);
+        Assert.assertEquals(8, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(1);
+        Assert.assertEquals(9, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-9);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-10);
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(2);
+        Assert.assertEquals(2, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(2);
+        Assert.assertEquals(4, viewState.getSelection());
+
+        viewState = this.calculatorEditor.moveSelection(-6);
+        Assert.assertEquals(0, viewState.getSelection());
+    }
+
+    @Test
+    public void testSetText() throws Exception {
+        CalculatorEditorViewState viewState = this.calculatorEditor.setText("test");
+
+        Assert.assertEquals("test", viewState.getText());
+        Assert.assertEquals(4, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("testtest");
+        Assert.assertEquals("testtest", viewState.getText());
+        Assert.assertEquals(8, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("");
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("testtest", 0);
+        Assert.assertEquals("testtest", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("testtest", 2);
+        Assert.assertEquals("testtest", viewState.getText());
+        Assert.assertEquals(2, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("", 0);
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("", 3);
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("", -3);
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("test");
+        Assert.assertEquals("test", viewState.getText());
+        Assert.assertEquals(4, viewState.getSelection());
+
+        viewState = this.calculatorEditor.setText("", 2);
+        Assert.assertEquals("", viewState.getText());
+        Assert.assertEquals(0, viewState.getSelection());
+    }
+}

calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java

@@ -537,10 +537,8 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	public void eraseButtonClickHandler(@NotNull View v) {
 		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
 			@Override
-			public void doOperation(@NotNull EditText editor) {
+			public void doOperation(@NotNull CalculatorEditor editor) {
-				if (editor.getSelectionStart() > 0) {
+				editor.erase();
-					editor.getText().delete(editor.getSelectionStart() - 1, editor.getSelectionStart());
-				}
 			}
 		});
 	}
@@ -564,10 +562,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	public void pasteButtonClickHandler(@NotNull View v) {
 		calculatorModel.doTextOperation(new CalculatorModel.TextOperation() {
 			@Override
-			public void doOperation(@NotNull EditText editor) {
+			public void doOperation(@NotNull CalculatorEditor editor) {
 				final ClipboardManager clipboard = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
 				if (clipboard.hasText()) {
-					editor.getText().insert(editor.getSelectionStart(), clipboard.getText());
+                    editor.insert(String.valueOf(clipboard.getText()));
 				}
 			}
 		});
@@ -754,15 +752,18 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 			if ( dragDirection == DragDirection.left ) {
 				CalculatorModel.instance.doTextOperation(new CalculatorModel.TextOperation() {
 					@Override
-					public void doOperation(@NotNull EditText editor) {
+					public void doOperation(@NotNull CalculatorEditor editor) {
-						final int cursorPosition = editor.getSelectionStart();
+                        CalculatorEditorViewState viewState = editor.getViewState();
-						final StringBuilder text = new StringBuilder("(");
+
-						final String oldText = editor.getText().toString();
+                        final int cursorPosition = viewState.getSelection();
-						text.append(oldText.substring(0, cursorPosition));
+                        final String oldText = viewState.getText();
-						text.append(")");
+
-						text.append(oldText.substring(cursorPosition));
+                        final StringBuilder newText = new StringBuilder(oldText.length() + 2);
-						editor.setText(text);
+                        newText.append("(");
-						editor.setSelection(cursorPosition + 2);
+						newText.append(oldText.substring(0, cursorPosition));
+						newText.append(")");
+						newText.append(oldText.substring(cursorPosition));
+						editor.setText(newText.toString(), cursorPosition + 2);
 					}
 				});
 				result = true;

calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorModel.java

@@ -14,7 +14,6 @@ import android.text.ClipboardManager;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.Toast;
 import org.jetbrains.annotations.NotNull;
@@ -37,7 +36,7 @@ import org.solovyev.common.text.StringUtils;
  * Date: 9/12/11
  * Time: 11:15 PM
  */
-public enum CalculatorModel implements HistoryControl<CalculatorHistoryState>, CalculatorEngineControl {
+public enum CalculatorModel implements HistoryControl<CalculatorHistoryState>, CalculatorEngineControl, CursorControl {
 
 	instance;
 
@@ -271,7 +270,7 @@ public enum CalculatorModel implements HistoryControl<CalculatorHistoryState>, C
 			doTextOperation(new CalculatorModel.TextOperation() {
 
 				@Override
-				public void doOperation(@NotNull EditText editor) {
+				public void doOperation(@NotNull CalculatorEditor editor) {
 					int cursorPositionOffset = 0;
 					final StringBuilder textToBeInserted = new StringBuilder(text);
 
@@ -296,16 +295,36 @@ public enum CalculatorModel implements HistoryControl<CalculatorHistoryState>, C
 						}
 					}
 
-					editor.getText().insert(editor.getSelectionStart(), textToBeInserted.toString());
+					editor.insert(textToBeInserted.toString());
-					editor.setSelection(editor.getSelectionStart() + cursorPositionOffset, editor.getSelectionEnd() + cursorPositionOffset);
+					editor.moveSelection(cursorPositionOffset);
 				}
 			}, delayEvaluate);
 		}
 	}
 
-	public static interface TextOperation {
+    @Override
+    public void setCursorOnStart() {
+        this.editor.setCursorOnStart();
+    }
 
-		void doOperation(@NotNull EditText editor);
+    @Override
+    public void setCursorOnEnd() {
+        this.editor.setCursorOnEnd();
+    }
+
+    @Override
+    public void moveCursorLeft() {
+        this.editor.moveCursorLeft();
+    }
+
+    @Override
+    public void moveCursorRight() {
+        this.editor.moveCursorRight();
+    }
+
+    public static interface TextOperation {
+
+		void doOperation(@NotNull CalculatorEditor editor);
 
 	}
 

calculatorpp/src/main/java/org/solovyev/android/calculator/history/AbstractHistoryActivity.java

@@ -14,12 +14,13 @@ import android.view.MenuItem;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
-import android.widget.EditText;
 import android.widget.ListView;
 import com.google.ads.AdView;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.ads.AdsController;
+import org.solovyev.android.calculator.CalculatorEditor;
+import org.solovyev.android.calculator.CalculatorLocatorImpl;
 import org.solovyev.android.calculator.CalculatorModel;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.jscl.JsclOperation;
@@ -175,19 +176,8 @@ public abstract class AbstractHistoryActivity extends ListActivity {
 	}
 
 	public static void useHistoryItem(@NotNull final CalculatorHistoryState historyState, @NotNull AbstractHistoryActivity activity) {
-
+        final EditorHistoryState editorState = historyState.getEditorState();
-		// before evaluating history item - clear display (in order to get Error message in display if evaluation fail)
+        CalculatorLocatorImpl.getInstance().getCalculatorEditor().setText(StringUtils.getNotEmpty(editorState.getText(), ""), editorState.getCursorPosition())
-		CalculatorModel.instance.getDisplay().setText("");
-		CalculatorModel.instance.doTextOperation(new CalculatorModel.TextOperation() {
-			@Override
-			public void doOperation(@NotNull EditText editor) {
-				final EditorHistoryState editorState = historyState.getEditorState();
-				editor.setText(editorState.getText());
-				editor.setSelection(editorState.getCursorPosition());
-			}
-		}, false, historyState.getDisplayState().getJsclOperation(), true);
-
-		CalculatorModel.instance.setCursorOnEnd();
 
 		activity.finish();
 	}