waitForElementToDisappear for all the panels of the page - selenium

Question

By panelCollapseSelector = By.cssSelector(".panel-heading+.panel-collapse");
waitForElementToDisappear(panelCollapseSelector);
The above code waits for the 1st panel of the page. I would like to wait for all the panels to collapse. How can I run loop around this.to wait for all the panels of the page.
code before collapse
<div class="panel-collapse collapse in" style="height: auto;">
code after collapse
<div class="panel-collapse collapse" style="height: 0px;">

Answer 1

A simple solution would be to wait for 0 elements matching the non collapsed panels.
One possible CSS selector to get all the non collapsed panels:
".panel-heading:not(.in) + .panel-collapse:not(.in)"
Then to wait with a lambda expression :
WebDriverWait wait = new WebDriverWait(driver, 20);
wait.until((WebDriver drv) -> drv.findElements(By.cssSelector(
".panel-heading:not(.in) + .panel-collapse:not(.in)")).size() == 0);
Or using the expected conditions:
WebDriverWait wait = new WebDriverWait(driver, 20);
wait.until(ExpectedConditions.not(ExpectedConditions.presenceOfAllElementsLocatedBy(
By.cssSelector(".panel-heading:not(.in) + .panel-collapse:not(.in)"))));

Answer 2

You can try this java method for waiting 60 seconds for all panels to get collapse
int timeout=60;
while(driver.findElement(By.cssSelector(".panel-heading+.panel-collapse")).getAttribute("style").contains("height: auto;") && timeout > 0) {
try {
if(timeout>1)
{
timeout--;
System.out.println("====== Waiting for Collapsing Panels ======");
Thread.sleep(1000);
}
}
catch(Exception e) {
}