private int getValue(String proposedText) {
			if (proposedText.isBlank()) {
				return 1;
			}
			try {
				return Integer.parseInt(proposedText);
			}
			catch (NumberFormatException e) {
				return -1;
			}
		}
Called before new user input is inserted into the entry text field.  The super
method is called if the input is accepted.
Ghidra/Features/Base/src/main/java/ghidra/features/base/memsearch/gui/MemorySearchOptionsPanel.java