JsCache.java

/*
 * Copyright 2011, The gwtquery team.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.query.client.js;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsArrayMixed;
import com.google.gwt.core.client.JsArrayString;

/**
  * A Lightweight JSO class to store data.
  */
public class JsCache extends JavaScriptObject {

  protected JsCache() {
  }

  public static JsCache create() {
    return createObject().cast();
  }

  public final native void concat(Object ary) /*-{
    if (ary) this.concat(ary);
  }-*/;

  public final void copy(JsCache jso) {
    for (String k : jso.keys()) {
      put(k, jso.get(k));
    }
  }

  public final void pushAll(JavaScriptObject prevElem) {
    checkNull();
    JsCache c = prevElem.cast();
    for (int i = 0, ilen = c.length(); i < ilen; i++) {
      put(length(), c.get(i));
    }
  }

  public final native void delete(Object name) /*-{
    delete this[name];
  }-*/;

  public final void clear() {
    for (String k : keys()) {
      delete(k);
    }
  }

  public final native boolean exists(Object name) /*-{
    return !!this[name];
  }-*/;

  @SuppressWarnings("unchecked")
  public final <T> T get(Object id, Class<? extends T> clz) {
    Object o = get(id);
    if (o != null && clz != null) {
      if (o instanceof Double) {
        Double d = (Double) o;
        if (clz == Float.class)
          o = d.floatValue();
        else if (clz == Integer.class)
          o = d.intValue();
        else if (clz == Long.class)
          o = d.longValue();
        else if (clz == Short.class)
          o = d.shortValue();
        else if (clz == Byte.class)
          o = d.byteValue();
      } else if (clz == Boolean.class && !(o instanceof Boolean)) {
        o = Boolean.valueOf(String.valueOf(o));
      } else if (clz == String.class && !(o instanceof String)) {
        o = String.valueOf(o);
      }
    }
    return (T) o;
  }

  public final native <T> T get(Object id) /*-{
    return @com.google.gwt.query.client.js.JsCache::gwtBox(*)([ this && this[id] ]);
  }-*/;

  public final JsCache getCache(int id) {
    return (JsCache) get(id);
  }

  public final boolean getBoolean(Object id) {
    Boolean r = get(id, Boolean.class);
    return r == null ? false : r;
  }

  public final float getFloat(Object id) {
    Float r = get(id, Float.class);
    return r == null ? 0 : r;
  }

  public final double getDouble(Object id) {
    Double r = get(id, Double.class);
    return r == null ? 0 : r;
  }

  public final int getInt(Object id) {
    Integer r = get(id, Integer.class);
    return r == null ? 0 : r;
  }

  public final native String getString(Object id) /*-{
    return this[id] == null ? null : String(this[id]);
  }-*/;

  public final native JsArrayMixed getArray(Object id) /*-{
    var r = this[id];
    if (Object.prototype.toString.call(r) == '[object Array]') {
      return r;
    }
    return null;
  }-*/;

  public final <T extends JavaScriptObject> T getJavaScriptObject(Object name) {
    Object o = get(name);
    return (o != null && o instanceof JavaScriptObject) ? ((JavaScriptObject) o).<T> cast() : null;
  }

  public final native boolean isEmpty() /*-{
    for (k in this) {
     if (this.hasOwnProperty(k))
       return false;
    }
    return true;
  }-*/;

  public final native boolean contains(Object o) /*-{
    return this.indexOf(o) >= 0;
  }-*/;

  public final native void remove(Object o) /*-{
    var i = this.indexOf(o);
    if (i >= 0) this.splice(i, 1);
  }-*/;

  public final native int indexOf(Object o) /*-{
    // HtmlUnit fails when this returns 0
    return this.indexOf(o);
  }-*/;

  public final native JsCache putBoolean(Object id, boolean b) /*-{
    this[id] = b;
    return this;
  }-*/;

  public final native JsCache putNumber(Object id, double n) /*-{
    this[id] = n;
    return this;
  }-*/;

  public final JsCache put(Object id, Object obj) {
    if (obj instanceof Boolean) {
      putBoolean(id, (Boolean) obj);
    } else if (obj instanceof Number) {
      putNumber(id, ((Number) obj).doubleValue());
    } else {
      putObject(id, obj);
    }
    return this;
  }

  public final native JsCache putObject(Object id, Object obj) /*-{
    this[id] = obj;
    return this;
  }-*/;

  public final native int length() /*-{
    if (typeof(this.length) == 'number')
     return this.length;

    var key, ret = 0;
    // Chrome in DevMode injects a property to JS objects
    for (key in this) {
      if (key != "__gwt_ObjectId")
         ret ++;
    }
    return ret;
  }-*/;

  public final int[] indexes() {
    checkNull();
    JsArrayString a = keysImpl();
    int[] ret = new int[a.length()];
    for (int i = 0; i < a.length(); i++) {
      try {
        ret[i] = Integer.valueOf(a.get(i));
      } catch (Exception e) {
        ret[i] = i;
      }
    }
    return ret;
  }

  public final String[] keys() {
    checkNull();
    JsArrayString a = keysImpl();
    String[] ret = new String[a.length()];
    for (int i = 0; i < a.length(); i++) {
      ret[i] = a.get(i);
    }
    return ret;
  }

  public final Object[] elements() {
    String[] keys = keys();
    Object[] ret = new Object[keys.length];
    int i = 0;
    for (String s : keys) {
      ret[i++] = get(s);
    }
    return ret;
  }

  public final String tostring() {
    String ret = getClass().getName() + "{ ";
    for (String k : keys()) {
      ret += k + "=" + get(k) + " ";
    }
    return ret + "}";
  }

  // In dev-mode a null object casted to JavascriptObject does not throw a NPE
  public final void checkNull() {
    checkNull(this);
  }

  private native JsArrayString keysImpl() /*-{
    var key, keys=[];
    // Chrome in DevMode sets '__gwt_ObjectId' to JS objects
    // GWT sets '$H' when calling getHashCode (see com/google/gwt/core/client/impl/Impl.java)
    for(key in this) {
      if (this.hasOwnProperty(key) && key != '__gwt_ObjectId' && key != '$H')
        keys.push(String(key));
    }
    return keys;
  }-*/;

  /**
   * Throw a NPE when a js is null.
   */
  public static final <T extends JavaScriptObject> T checkNull(T js) {
    if (!GWT.isProdMode() && js == null) {
      throw new NullPointerException();
    }
    return js;
  }

  /**
   * Gets an object wrapped in a js array and boxes it with the appropriate
   * object in the GWT world.
   *
   * It is thought to be called from other jsni code without dealing with casting issues.
   *
   * It will box the unique element in the array with a Boolean or a Double in the case
   * of primitive variables, otherwise it returns the object itself, or null if undefined.
   *
   * Example
   * <pre>
   * native Object myMethod() /*-{
   *   var myJsVar = ... ;
   *   return @com.google.gwt.query.client.js.JsCache::gwtBox(*)([ myJsVar ]);
   * }-* /
   * </pre>
   *
   */
  public static native Object gwtBox(JavaScriptObject oneElementArray) /*-{
    var r = oneElementArray;
    if (typeof r == 'object' && r.length == 1) {
      var r = r[0], t = typeof r;
      if (t == 'boolean') return @java.lang.Boolean::valueOf(Z)(r);
      if (t == 'number')  return @java.lang.Double::valueOf(D)(r);
    }
    return r || null;
  }-*/;
}