/*
* Copyright 2008 Google Inc.
*
* 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.dev.shell;
/**
* Represents a JavaScript value.
*
* Note that in general the various get*() methods will return
* platform-independent values only if the corresponding is*() method returns
* true. In some cases, an IllegalStateException may be thrown if the JavaScript
* value is not of the appropriate type or bogus values may be returned. Note
* that getString will try very hard to return a reasonable result for any
* value, but it is intended only for human consumption and the exact format for
* anything besides a string value cannot be relied upon.
*/
public abstract class JsValue {
/**
* Provides interface for methods to be exposed on JavaScript side.
*/
public interface DispatchMethod {
boolean invoke(JsValue jsthis, JsValue[] jsargs, JsValue returnValue);
}
/**
* Provides interface for objects to be exposed on JavaScript side.
*/
public interface DispatchObject {
JsValue getField(int dispatchId);
JsValue getField(String name);
int getFieldId(String name);
Object getTarget();
void setField(int dispatchId, JsValue value);
void setField(String name, JsValue value);
}
/**
* Get the value of the object as a boolean. May attempt to convert the value
* to a boolean if it is not a boolean.
*
* @return the value of the underlying object as a boolean
*/
public abstract boolean getBoolean();
/**
* Get the value of the object as an integer. May attempt to convert the value
* to an integer if it is not an integer.
*
* @return the value of the underlying object as an int
*/
public abstract int getInt();
/**
* Get the wrapper object for a wrapped Java object. Only valid if
* isWrappedJavaObject() is true.
*
* @return the Java object wrapper
*/
public abstract DispatchObject getJavaObjectWrapper();
/**
* Returns a unique value corresponding to the underlying JavaScript object.
* In general, two different JsValues will return the same value IFF the
* underlying JavaScript objects are identical (===).
*
* @return a unique number corresponding to the underlying object, or
* <code>0</code> if {@link #isJavaScriptObject()} is
* <code>false</code>
*/
public abstract int getJavaScriptObjectPointer();
/**
* Get the value of the object as a double. May attempt to convert the value
* to a double if it is not a double.
*
* @return the value of the underlying object as a double
*/
public abstract double getNumber();
/**
* Get the value of the object as a string. Will coerce the underlying type to
* a string, but stable cross-platform behavior is only guaranteed when
* {@link #isString()} is <code>true</code>.
*
* @return the value of the underlying object as a string
*/
public abstract String getString();
/**
* Returns a human-readable string describing the type of the JS object. This
* is intended only for human consumption and may vary across platforms.
*/
public abstract String getTypeString();
/**
* Returns a wrapped Java method.
*/
public abstract DispatchMethod getWrappedJavaFunction();
/**
* Unwrap a wrapped Java object.
*
* @return the original Java object wrapped in this JS object
*/
public abstract Object getWrappedJavaObject();
/**
* Returns true if the JS value is a boolean.
*/
public abstract boolean isBoolean();
/**
* Returns true if getInt() can be used on this value.
*/
public abstract boolean isInt();
/**
* Returns true if the JS value is a native JS object.
*/
public abstract boolean isJavaScriptObject();
/**
* Returns true if the JS value is null.
*/
public abstract boolean isNull();
/**
* Returns true if the JS value is a numeric type.
*/
public abstract boolean isNumber();
/**
* Returns true if the JS value is a string.
*/
public abstract boolean isString();
/**
* Returns true if the JS value is undefined (void).
*/
public abstract boolean isUndefined();
/**
* Returns true if the JS value contains a wrapped Java method.
*/
public abstract boolean isWrappedJavaFunction();
/**
* Returns true if the JS value is a wrapped Java object.
*/
public abstract boolean isWrappedJavaObject();
/**
* Sets the JS object to be a boolean value.
*
* @param val the boolean value to set
*/
public abstract void setBoolean(boolean val);
/**
* Sets the JS object to be a number, passed as an byte.
*
* @param val the value to store
*/
public abstract void setByte(byte val);
/**
* Sets the JS object to be a number, passed as a char.
*
* @param val the value to store
*/
public abstract void setChar(char val);
/**
* Sets the JS object to be a number, passed as a double.
*
* @param val the value to store
*/
public abstract void setDouble(double val);
/**
* Sets the JS object to be a number, passed as an int.
*
* @param val the value to store
*/
public abstract void setInt(int val);
/**
* Set the JS object to be null.
*
* @throws com.google.gwt.dev.shell.HostedModeException
*/
public abstract void setNull();
/**
* Sets the JS object to be a number, passed as a short.
*
* @param val the value to store
*/
public abstract void setShort(short val);
/**
* Set the JS object to the supplied string.
*
* @param val the string to put in the JS object
* @throws HostedModeException on JS allocation failures
*/
public abstract void setString(String val);
/**
* Set the JS object to be undefined (void).
*
* @throws HostedModeException on JS allocation failures
*/
public abstract void setUndefined();
/**
* Make this JsValue refer to the same underlying object as another JsValue.
*
* @param other JsValue to copy JS object from
*/
public abstract void setValue(JsValue other);
/**
* Set the JS object to the supplied object, which will be wrapped in a
* platform-dependent JavaScript class.
*
* @param <T> the type of the Java object to wrap
* @param cl the classloader to create the wrapper object with
* @param val the Java object to wrap
* @throws HostedModeException
*/
public abstract <T> void setWrappedJavaObject(CompilingClassLoader cl, T val);
/**
* Produce a string representation of the JsValue.
*/
@Override
public String toString() {
if (isUndefined()) {
return "void";
} else if (isNull()) {
return "null";
} else if (isBoolean()) {
return "bool: " + (getBoolean() ? "true" : "false");
} else if (isInt()) {
return "int: " + Integer.toString(getInt());
} else if (isNumber()) {
return "double: " + Double.toString(getNumber());
} else if (isWrappedJavaObject()) {
Object wrappedObject = getWrappedJavaObject();
if (wrappedObject == null) {
return "Java static dispatch";
}
// avoid calling toString on the wrapped object, as this can be expensive
return "Java object: " + wrappedObject.getClass().getName() + '@'
+ System.identityHashCode(wrappedObject);
} else if (isJavaScriptObject()) {
return getTypeString();
} else if (isString()) {
return "string: '" + getString() + "'";
} else if (isWrappedJavaFunction()) {
return "Java method: " + getWrappedJavaFunction().toString();
}
return getTypeString();
}
}