docs: public void postConstruct() throws URISyntaxException {
          WmsVersion.lookup(this.version);
          Assert.isTrue(validateBaseUrl(), "invalid baseURL");
  
          Assert.isTrue(this.layers.length > 0, "There must be at least one layer defined for a WMS request" +
                  " to make sense");
  
          // OpenLayers 2 compatibility.  It will post a single empty style no matter how many layers there are
  
          if (this.styles != null && this.styles.length != this.layers.length && this.styles.length == 1 &&
                  this.styles[0].trim().isEmpty()) {
              this.styles = null;
          } else {
              Assert.isTrue(this.styles == null || this.layers.length == this.styles.length,
                            String.format(
                                    "If styles are defined then there must be one for each layer.  Number of" +
                                            " layers: %s\nStyles: %s", this.layers.length,
                                    Arrays.toString(this.styles)));
          }
  
          if (this.imageFormat.indexOf('/') < 0) {
              LOGGER.warn("The format {} should be a mime type", this.imageFormat);
              this.imageFormat = "image/" + this.imageFormat;
          }
  
          Assert.isTrue(this.method == HttpMethod.GET || this.method == HttpMethod.POST,
                        String.format("Unsupported method %s for WMS layer", this.method.toString()));
      }