Polymer elements added to third_party/polymer.

third_party/polymer/components/core-meta/core-meta.html

+<!--
+Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+
+<!--
+`core-meta` provides a method of constructing a self-organizing database.
+It is useful to collate element meta-data for things like catalogs and for 
+designer.
+
+Example, an element folder has a `metadata.html` file in it, that contains a 
+`core-meta`, something like this:
+
+    <core-meta id="my-element" label="My Element">
+      <property name="color" value="blue"></property>
+    </core-meta>
+
+An application can import as many of these files as it wants, and then use 
+`core-meta` again to access the collected data.
+
+    <script>
+      var meta = document.createElement('core-meta');
+      console.log(meta.list); // dump a list of all meta-data elements that have been created
+    </script>
+
+Use `byId(id)` to retrive a specific core-meta.
+
+    <script>
+      var meta = document.createElement('core-meta');
+      console.log(meta.byId('my-element'));
+    </script>
+
+By default all meta-data are stored in a single databse.  If your meta-data 
+have different types and want them to be stored separately, use `type` to 
+differentiate them.
+
+Example:
+
+    <core-meta id="x-foo" type="xElt"></core-meta>
+    <core-meta id="x-bar" type="xElt"></core-meta>
+    <core-meta id="y-bar" type="yElt"></core-meta>
+
+    <script>
+      var meta = document.createElement('core-meta');
+      meta.type = 'xElt';
+      console.log(meta.list);
+    </script>
+
+@group Polymer Core Elements
+@element core-meta
+@homepage github.io
+-->
+
+<link rel="import" href="../polymer/polymer.html">
+
+<polymer-element name="core-meta" attributes="label type" hidden>
+<script>
+
+  (function() {
+    
+    var SKIP_ID = 'meta';
+    var metaData = {}, metaArray = {};
+
+    Polymer('core-meta', {
+      
+      /**
+       * The type of meta-data.  All meta-data with the same type with be
+       * stored together.
+       * 
+       * @attribute type
+       * @type string
+       * @default 'default'
+       */
+      type: 'default',
+      
+      alwaysPrepare: true,
+      
+      ready: function() {
+        this.register(this.id);
+      },
+      
+      get metaArray() {
+        var t = this.type;
+        if (!metaArray[t]) {
+          metaArray[t] = [];
+        }
+        return metaArray[t];
+      },
+      
+      get metaData() {
+        var t = this.type;
+        if (!metaData[t]) {
+          metaData[t] = {};
+        }
+        return metaData[t];
+      },
+      
+      register: function(id, old) {
+        if (id && id !== SKIP_ID) {
+          this.unregister(this, old);
+          this.metaData[id] = this;
+          this.metaArray.push(this);
+        }
+      },
+      
+      unregister: function(meta, id) {
+        delete this.metaData[id || meta.id];
+        var i = this.metaArray.indexOf(meta);
+        if (i >= 0) {
+          this.metaArray.splice(i, 1);
+        }
+      },
+      
+      /**
+       * Returns a list of all meta-data elements with the same type.
+       * 
+       * @property list
+       * @type array
+       * @default []
+       */
+      get list() {
+        return this.metaArray;
+      },
+      
+      /**
+       * Retrieves meta-data by ID.
+       *
+       * @method byId
+       * @param {String} id The ID of the meta-data to be returned.
+       * @returns Returns meta-data.
+       */
+      byId: function(id) {
+        return this.metaData[id];
+      }
+      
+    });
+    
+  })();
+  
+</script>
+</polymer-element>