PL-8178 Before/After listeners on ClearButton click action for FileUploadField

modules/desktop/src/com/haulmont/cuba/desktop/gui/components/DesktopFileUploadField.java

@@ -81,6 +81,10 @@ public class DesktopFileUploadField extends DesktopAbstractUploadField<CubaFileU
     protected List<FileUploadFinishListener> fileUploadFinishListeners;   // lazily initialized list
     protected List<FileUploadSucceedListener> fileUploadSucceedListeners; // lazily initialized list
     protected List<FileUploadErrorListener> fileUploadErrorListeners;     // lazily initialized list
+
+    protected List<BeforeValueClearListener> beforeValueClearListeners; // lazily initialized list
+    protected List<AfterValueClearListener> afterValueClearListeners; // lazily initialized list
+
     protected FileDescriptor prevValue;
 
     public DesktopFileUploadField() {
@@ -121,10 +125,30 @@ public class DesktopFileUploadField extends DesktopAbstractUploadField<CubaFileU
                     exportDisplay.show(value);
             }
         });
-        impl.setClearButtonListener(() -> {
+        impl.setClearButtonListener(this::clearButtonClicked);
+    }
+
+    protected void clearButtonClicked() {
+        boolean preventClearAction = false;
+        if (beforeValueClearListeners != null) {
+            BeforeValueClearEvent beforeValueClearEvent = new BeforeValueClearEvent(this);
+            for (BeforeValueClearListener listener : new ArrayList<>(beforeValueClearListeners)) {
+                listener.beforeValueClearPerformed(beforeValueClearEvent);
+            }
+            preventClearAction = beforeValueClearEvent.isClearPrevented();
+        }
+
+        if (!preventClearAction) {
             setValue(null);
             fileName = null;
-        });
+        }
+
+        if (afterValueClearListeners != null) {
+            AfterValueClearEvent afterValueClearEvent = new AfterValueClearEvent(this, !preventClearAction);
+            for (AfterValueClearListener listener : new ArrayList<>(afterValueClearListeners)) {
+                listener.afterValueClearPerformed(afterValueClearEvent);
+            }
+        }
     }
 
     protected void uploadFile(File file) {
@@ -719,4 +743,38 @@ public class DesktopFileUploadField extends DesktopAbstractUploadField<CubaFileU
     public String getClearButtonDescription() {
         return impl.getClearButtonDescription();
     }
+
+    @Override
+    public void addBeforeValueClearListener(BeforeValueClearListener listener) {
+        if (beforeValueClearListeners == null) {
+            beforeValueClearListeners = new ArrayList<>();
+        }
+        if (!beforeValueClearListeners.contains(listener)) {
+            beforeValueClearListeners.add(listener);
+        }
+    }
+
+    @Override
+    public void removeBeforeValueClearListener(BeforeValueClearListener listener) {
+        if (beforeValueClearListeners != null) {
+            beforeValueClearListeners.remove(listener);
+        }
+    }
+
+    @Override
+    public void addAfterValueClearListener(AfterValueClearListener listener) {
+        if (afterValueClearListeners == null) {
+            afterValueClearListeners = new ArrayList<>();
+        }
+        if (!afterValueClearListeners.contains(listener)) {
+            afterValueClearListeners.add(listener);
+        }
+    }
+
+    @Override
+    public void removeAfterValueClearListener(AfterValueClearListener listener) {
+        if (afterValueClearListeners != null) {
+            afterValueClearListeners.remove(listener);
+        }
+    }
 }

modules/gui/src/com/haulmont/cuba/gui/components/FileUploadField.java

@@ -142,16 +142,15 @@ public interface FileUploadField extends UploadField, Field {
      * Enable or disable displaying name of uploaded file next to upload button.
      */
     void setShowFileName(boolean showFileName);
-
     /**
      * @return true if name of uploaded file is shown.
      */
     boolean isShowFileName();
+
     /**
      * Setup caption of upload button.
      */
     void setUploadButtonCaption(String caption);
-
     /**
     * @return upload button caption.
     */
@@ -161,7 +160,6 @@ public interface FileUploadField extends UploadField, Field {
      * Setup upload button icon.
      */
     void setUploadButtonIcon(String icon);
-
     /**
      * @return upload button icon.
      */
@@ -171,7 +169,6 @@ public interface FileUploadField extends UploadField, Field {
      * Setup upload button description.
      */
     void setUploadButtonDescription(String description);
-
     /**
      * @return upload button description.
      */
@@ -181,7 +178,6 @@ public interface FileUploadField extends UploadField, Field {
      * Enable or disable displaying name of clear button.
      */
     void setShowClearButton(boolean showClearButton);
-
     /**
      * @return true if clear button is shown.
      */
@@ -191,7 +187,6 @@ public interface FileUploadField extends UploadField, Field {
      * Setup clear button caption.
      */
     void setClearButtonCaption(String caption);
-
     /**
      * @return clear button caption.
      */
@@ -201,7 +196,6 @@ public interface FileUploadField extends UploadField, Field {
      * Setup clear button icon.
      */
     void setClearButtonIcon(String icon);
-
     /**
      * @return clear button icon.
      */
@@ -211,14 +205,77 @@ public interface FileUploadField extends UploadField, Field {
      * Setup clear button description.
      */
     void setClearButtonDescription(String description);
-
     /**
      * @return clear button description.
      */
     String getClearButtonDescription();
 
+    class BeforeValueClearEvent {
+        private FileUploadField target;
+        private boolean clearPrevented = false;
+
+        public BeforeValueClearEvent(FileUploadField target) {
+            this.target = target;
+        }
+
+        public boolean isClearPrevented() {
+            return clearPrevented;
+        }
+
+        public void preventClearAction() {
+            this.clearPrevented = true;
+        }
+
+        public FileUploadField getTarget() {
+            return target;
+        }
+    }
+
     /**
-     * Set mode which determines when {@link FileDescriptor} will be commited.
+     * Callback interface which is invoked by the {@link FileUploadField} before value clearing when user use clear button. <br/>
+     * Listener can prevent value clearing using {@link BeforeValueClearEvent#preventClearAction()}.
+     *
+     * @see #setShowClearButton(boolean)
+     */
+    interface BeforeValueClearListener {
+        void beforeValueClearPerformed(BeforeValueClearEvent event);
+    }
+
+    void addBeforeValueClearListener(BeforeValueClearListener listener);
+    void removeBeforeValueClearListener(BeforeValueClearListener listener);
+
+    class AfterValueClearEvent {
+        private FileUploadField target;
+        private boolean valueCleared;
+
+        public AfterValueClearEvent(FileUploadField target, boolean valueCleared) {
+            this.target = target;
+            this.valueCleared = valueCleared;
+        }
+
+        public FileUploadField getTarget() {
+            return target;
+        }
+
+        public boolean isValueCleared() {
+            return valueCleared;
+        }
+    }
+
+    /**
+     * Callback interface which is invoked by the {@link FileUploadField} after value has been cleared using clear button.
+     *
+     * @see #setShowClearButton(boolean)
+     */
+    interface AfterValueClearListener {
+        void afterValueClearPerformed(AfterValueClearEvent event);
+    }
+
+    void addAfterValueClearListener(AfterValueClearListener listener);
+    void removeAfterValueClearListener(AfterValueClearListener listener);
+
+    /**
+     * Set mode which determines when {@link FileDescriptor} will be committed.
      */
     void setMode(FileStoragePutMode mode);
     /**
@@ -231,10 +288,9 @@ public interface FileUploadField extends UploadField, Field {
      * <p>Passed content provider will be used for downloading by clicking the link with file name
      * or as source for {@link FileUploadField#getFileContent()} method.</p>
      *
-     * @param contentProvider
+     * @param contentProvider content provider
      */
     void setContentProvider(FileContentProvider contentProvider);
-
     /**
      * @return FileContentProvider which can be used to read data from field
      */

modules/web/src/com/haulmont/cuba/web/gui/components/CubaFileUploadWrapper.java

@@ -292,7 +292,7 @@ public class CubaFileUploadWrapper extends CustomField {
         return clearButton.getIcon().toString();
     }
 
-    public void setClearButtonAction(Button.ClickListener listener) {
+    public void setClearButtonListener(Button.ClickListener listener) {
         clearButton.addClickListener(listener);
     }
 

modules/web/src/com/haulmont/cuba/web/gui/components/WebFileUploadField.java

@@ -74,6 +74,9 @@ public class WebFileUploadField extends WebAbstractUploadField<CubaFileUploadWra
     protected List<FileUploadErrorListener> fileUploadErrorListeners;     // lazily initialized list
     protected List<FileUploadSucceedListener> fileUploadSucceedListeners; // lazily initialized list
 
+    protected List<BeforeValueClearListener> beforeValueClearListeners; // lazily initialized list
+    protected List<AfterValueClearListener> afterValueClearListeners; // lazily initialized list
+
     public WebFileUploadField() {
         fileUploading = AppBeans.get(FileUploadingAPI.NAME);
         exportDisplay = AppBeans.get(ExportDisplay.NAME);
@@ -105,10 +108,30 @@ public class WebFileUploadField extends WebAbstractUploadField<CubaFileUploadWra
                     exportDisplay.show(value);
             }
         });
-        component.setClearButtonAction((Button.ClickListener) event -> {
+        component.setClearButtonListener((Button.ClickListener) this::clearButtonClicked);
+    }
+
+    protected void clearButtonClicked(Button.ClickEvent clickEvent) {
+        boolean preventClearAction = false;
+        if (beforeValueClearListeners != null) {
+            BeforeValueClearEvent beforeValueClearEvent = new BeforeValueClearEvent(this);
+            for (BeforeValueClearListener listener : new ArrayList<>(beforeValueClearListeners)) {
+                listener.beforeValueClearPerformed(beforeValueClearEvent);
+            }
+            preventClearAction = beforeValueClearEvent.isClearPrevented();
+        }
+
+        if (!preventClearAction) {
             setValue(null);
             fileName = null;
-        });
+        }
+
+        if (afterValueClearListeners != null) {
+            AfterValueClearEvent afterValueClearEvent = new AfterValueClearEvent(this, !preventClearAction);
+            for (AfterValueClearListener listener : new ArrayList<>(afterValueClearListeners)) {
+                listener.afterValueClearPerformed(afterValueClearEvent);
+            }
+        }
     }
 
     protected void saveFile(FileDescriptor fileDescriptor) {
@@ -578,10 +601,12 @@ public class WebFileUploadField extends WebAbstractUploadField<CubaFileUploadWra
         this.mode = mode;
     }
 
+    @Override
     public boolean isShowFileName() {
         return component.isShowFileName();
     }
 
+    @Override
     public void setShowFileName(boolean showFileName) {
         component.setShowFileName(showFileName);
         if (showFileName && StringUtils.isNotEmpty(fileName)) {
@@ -645,6 +670,40 @@ public class WebFileUploadField extends WebAbstractUploadField<CubaFileUploadWra
         return component.getClearButtonDescription();
     }
 
+    @Override
+    public void addBeforeValueClearListener(BeforeValueClearListener listener) {
+        if (beforeValueClearListeners == null) {
+            beforeValueClearListeners = new ArrayList<>();
+        }
+        if (!beforeValueClearListeners.contains(listener)) {
+            beforeValueClearListeners.add(listener);
+        }
+    }
+
+    @Override
+    public void removeBeforeValueClearListener(BeforeValueClearListener listener) {
+        if (beforeValueClearListeners != null) {
+            beforeValueClearListeners.remove(listener);
+        }
+    }
+
+    @Override
+    public void addAfterValueClearListener(AfterValueClearListener listener) {
+        if (afterValueClearListeners == null) {
+            afterValueClearListeners = new ArrayList<>();
+        }
+        if (!afterValueClearListeners.contains(listener)) {
+            afterValueClearListeners.add(listener);
+        }
+    }
+
+    @Override
+    public void removeAfterValueClearListener(AfterValueClearListener listener) {
+        if (afterValueClearListeners != null) {
+            afterValueClearListeners.remove(listener);
+        }
+    }
+
     /*
     * Upload button
     * */