Java UndoManager.undo方法代码示例

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testUndoInvertsTheChange() {
    EventSource<Integer> changes = new EventSource<>();
    Var<Integer> lastAction = Var.newSimpleVar(null);
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes, i -> -i, i -> { lastAction.setValue(i); changes.push(i); });

    changes.push(3);
    changes.push(7);
    assertNull(lastAction.getValue());

    um.undo();
    assertEquals(-7, lastAction.getValue().intValue());

    um.undo();
    assertEquals(-3, lastAction.getValue().intValue());

    um.redo();
    assertEquals(3, lastAction.getValue().intValue());

    um.redo();
    assertEquals(7, lastAction.getValue().intValue());
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testMark() {
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.fixedSizeHistoryUndoManager(
            changes, c -> c, changes::push, 4);

    assertTrue(um.atMarkedPositionProperty().get());
    changes.push(1);
    assertFalse(um.atMarkedPositionProperty().get());
    changes.push(2);
    um.mark();
    assertTrue(um.atMarkedPositionProperty().get());
    changes.push(3);
    changes.push(4);
    assertFalse(um.atMarkedPositionProperty().get());
    um.undo();
    um.undo();
    assertTrue(um.atMarkedPositionProperty().get());
    changes.push(3);
    changes.push(4);
    changes.push(5); // overflow
    changes.push(6);
    assertFalse(um.atMarkedPositionProperty().get());
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testPushedNonIdentityChangeIsStored() {
    SimpleIntegerProperty lastAppliedValue = new SimpleIntegerProperty(0);
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes,
            i -> -i,    // invert
            i -> { lastAppliedValue.set(i); changes.push(i); }, // apply change and re-emit value so expected change is received
            (a, b) -> Optional.of(a + b), // merge adds two changes together
            i -> i == 0); // identity change = 0

    changes.push(4);
    assertTrue(um.isUndoAvailable());
    um.undo();
    assertEquals(-4, lastAppliedValue.get());
    assertFalse(um.isUndoAvailable());
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testPushedIdentityChangeIsNotStored() {
    SimpleIntegerProperty lastAppliedValue = new SimpleIntegerProperty(0);
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes,
            i -> -i,    // invert
            i -> { lastAppliedValue.set(i); changes.push(i); }, // apply change and re-emit value so expected change is received
            (a, b) -> Optional.of(a + b), // merge adds two changes together
            i -> i == 0); // identity change = 0

    // force lastAppliedValue to store non-zero value
    changes.push(4);
    um.undo();

    // test that pushed identity change is not stored
    changes.push(0);
    assertFalse(um.isUndoAvailable());
    assertEquals(-4, lastAppliedValue.get());
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testMergeResultingInNonIdentityChangeStoresMergeAndPreventsNextMerge() {
    SimpleIntegerProperty lastAppliedValue = new SimpleIntegerProperty(0);
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes,
            i -> -i,    // invert
            i -> { lastAppliedValue.set(i); changes.push(i); }, // apply change and re-emit value so expected change is received
            (a, b) -> Optional.of(a + b), // merge adds two changes together
            i -> i == 0); // identity change = 0

    changes.push(1);
    changes.push(2);
    assertTrue(um.isUndoAvailable());
    um.undo();
    assertFalse(um.isUndoAvailable());
    assertEquals(-3, lastAppliedValue.get());

    um.redo(); // redo to test whether merge occurs on next push
    changes.push(5);
    assertTrue(um.isUndoAvailable());
    um.undo();
    assertEquals(-5, lastAppliedValue.get());
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test(expected = IllegalStateException.class)
public void testFailFastWhenExpectedChangeNotReceived() {
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes, i -> -i, i -> {});

    changes.push(1);

    um.undo(); // should throw because the undone change is not received back
}
 

import org.fxmisc.undo.UndoManager; //导入方法依赖的package包/类
@Test
public void testMergeResultingInIdentityChangeAnnihilatesBothAndPreventsNextMerge() {
    SimpleIntegerProperty lastAppliedValue = new SimpleIntegerProperty(0);
    EventSource<Integer> changes = new EventSource<>();
    UndoManager<?> um = UndoManagerFactory.unlimitedHistoryUndoManager(
            changes,
            i -> -i,    // invert
            i -> { lastAppliedValue.set(i); changes.push(i); }, // apply change and re-emit value so expected change is received
            (a, b) -> Optional.of(a + b), // merge adds two changes together
            i -> i == 0); // identity change = 0

    // have at least one change stored
    changes.push(6);
    // prevent next merge from occurring
    um.preventMerge();

    // now push the identity-resulting merge changes
    changes.push(-3);   // change A
    changes.push(3);    // change B

    // changes should annihilate; neither are stored
    assertTrue(um.isUndoAvailable());
    um.undo();
    assertFalse(um.isUndoAvailable());
    assertEquals(-6, lastAppliedValue.get());

    um.redo(); // redo to test whether merge occurs on next push
    changes.push(3);
    assertTrue(um.isUndoAvailable());
    um.undo();
    assertTrue(um.isUndoAvailable());
    assertEquals(-3, lastAppliedValue.get());
}