Helper class for fetching CSS property values from stylesheets.

svn changeset:5058/svn branch:trunk

diff --git a/src/com/itmill/toolkit/terminal/gwt/client/CSSRule.java b/src/com/itmill/toolkit/terminal/gwt/client/CSSRule.java
new file mode 100644 (file)
index 0000000..d7cca24
--- /dev/null
+++ b/src/com/itmill/toolkit/terminal/gwt/client/CSSRule.java
@@ -0,0 +1,84 @@
+package com.itmill.toolkit.terminal.gwt.client;
+
+import com.google.gwt.core.client.JavaScriptObject;
+
+/**
+ * Utility class for fetching CSS properties from DOM StyleSheets JS object.
+ */
+public class CSSRule {
+
+    private final String selector;
+    private JavaScriptObject rules = null;
+
+    public CSSRule(String selector) {
+        this.selector = selector;
+        fetchRule(selector);
+    }
+
+    // TODO how to find the right LINK-element? We should probably give the
+    // stylesheet a name.
+    private native void fetchRule(final String selector)
+    /*-{
+        this.@com.itmill.toolkit.terminal.gwt.client.CSSRule::rules = @com.itmill.toolkit.terminal.gwt.client.CSSRule::searchForRule(Lcom/google/gwt/core/client/JavaScriptObject;Ljava/lang/String;)($doc.styleSheets[1], selector);
+    }-*/;
+
+    /*
+     * Loops through all current style rules and collects all matching to
+     * 'rules' array. The array is reverse ordered (last one found is first).
+     */
+    private static native JavaScriptObject searchForRule(
+            JavaScriptObject sheet, final String selector)
+    /*-{
+    if(!$doc.styleSheets)
+        return null;
+        
+    selector = selector.toLowerCase();
+    
+    var allMatches = [];
+    
+    var theRules = new Array();
+    if (sheet.cssRules)
+        theRules = sheet.cssRules
+    else if (sheet.rules)
+        theRules = sheet.rules
+        
+        var j = theRules.length;
+        for(var i=0; i<j; i++) {
+            var r = theRules[i];
+            if(r.type == 3) {
+                allMatches.unshift(@com.itmill.toolkit.terminal.gwt.client.CSSRule::searchForRule(Lcom/google/gwt/core/client/JavaScriptObject;Ljava/lang/String;)(r.styleSheet, selector));
+            } else if(r.type == 1) {
+                var selectors = r.selectorText.toLowerCase().split(",");
+                var n = selectors.length;
+                for(var m=0; m<n; m++) {
+                    if(selectors[m].replace(/^\s+|\s+$/g, "") == selector) {
+                        allMatches.unshift(r);
+                        break; // No need to loop other selectors for this rule
+                    }
+                }
+            }
+        }
+        
+        return allMatches;
+    }-*/;
+
+    /**
+     * Returns a specific property value from this CSS rule.
+     * @param propertyName
+     * @return
+     */
+    public native String getPropertyValue(final String propertyName)
+    /*-{  
+        for(var i=0; i<this.@com.itmill.toolkit.terminal.gwt.client.CSSRule::rules.length; i++){
+            var value = this.@com.itmill.toolkit.terminal.gwt.client.CSSRule::rules[i].style[propertyName];
+            if(value)
+                return value;
+        }
+        return null;
+    }-*/;
+
+    public String getSelector() {
+        return selector;
+    }
+
+}