[Modern Find/Replace] Refactor FindReplaceDialog

The FindReplaceDialog's business-logic is now handled in the
FindReplacer.
The FindReplacer communicates using a FindReplaceStatus object which is
polled by FindReplaceDialog as needed and allows for displaying correct
messages in the Interface.

This Refactoring is required so that the business-logic can be reused in
the new FindReplace overlay, as proposed in issue eclipse-platform#1090

bundles/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/texteditor/FindAndReplaceMessageStatus.java

@@ -0,0 +1,67 @@
+/*******************************************************************************
+ * Copyright (c) 2023 Vector Informatik GmbH and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Vector Informatik GmbH - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.ui.texteditor;
+
+/**
+ * Use by FindAndReplace to signal warnings, errors and messages to
+ * FindAndReplaceDialog and FindAndReplaceOverlay.
+ *
+ * @since 3.17
+ */
+class FindAndReplaceMessageStatus {
+	private boolean error;
+	private boolean warning;
+	private String message;
+
+	public void resetStatus() {
+		error = false;
+		warning = false;
+		setMessage(""); //$NON-NLS-1$
+	}
+
+	public String getMessage() {
+		return message;
+	}
+
+	public void setMessage(String message) {
+		this.message = message;
+	}
+
+	public boolean isError() {
+		return error;
+	}
+
+	public void setError(boolean error) {
+		this.error = error;
+	}
+
+	public void setWarning(boolean warning) {
+		this.warning = warning;
+	}
+
+	public boolean isWarning() {
+		return warning;
+	}
+
+	@Override
+	public FindAndReplaceMessageStatus clone() {
+		FindAndReplaceMessageStatus ret = new FindAndReplaceMessageStatus();
+		ret.setMessage(message);
+		ret.setError(isError());
+		ret.setWarning(isWarning());
+		return ret;
+	}
+
+}