com.google.gwt.core.client.JavaScriptException Maven / Gradle / Ivy
/*
* 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.core.client;
import com.google.gwt.core.client.impl.JavaScriptExceptionBase;
/**
* Any JavaScript exceptions occurring within JSNI methods are wrapped as this
* class when caught in Java code. The wrapping does not occur until the
* exception passes out of JSNI into Java. Before that, the thrown object
* remains a native JavaScript exception object, and can be caught in JSNI as
* normal.
*
* The return value of {@link #getStackTrace()} may vary between browsers due to
* variations in the underlying error-reporting capabilities. When possible, the
* stack trace will be the stack trace of the underlying error object. If it is
* not possible to accurately report a stack trace, a zero-length array will be
* returned. In those cases where the underlying stack trace cannot be
* determined, {@link #fillInStackTrace()} can be called in the associated catch
* block to create a stack trace corresponding to the location where the
* JavaScriptException object was created.
*
*
* try {
* nativeMethod();
* } catch (JavaScriptException e) {
* if (e.getStackTrace().length == 0) {
* e.fillInStackTrace();
* }
* }
*
*/
public final class JavaScriptException extends JavaScriptExceptionBase {
private static final Object NOT_SET = new Object();
private static String getExceptionDescription(Object e) {
if (e instanceof JavaScriptObject) {
return getExceptionDescription0((JavaScriptObject) e);
} else {
return e + "";
}
}
private static native String getExceptionDescription0(JavaScriptObject e) /*-{
return (e == null) ? null : e.message;
}-*/;
private static String getExceptionName(Object e) {
if (e == null) {
return "null";
} else if (e instanceof JavaScriptObject) {
return getExceptionName0((JavaScriptObject) e);
} else if (e instanceof String) {
return "String";
} else {
return e.getClass().getName();
}
}
private static native String getExceptionName0(JavaScriptObject e) /*-{
return (e == null) ? null : e.name;
}-*/;
/**
* The original description of the JavaScript exception this class wraps,
* initialized as e.message.
*/
private String description = "";
/**
* The underlying exception this class wraps.
*/
private final Object e;
/**
* A constructed message describing this exception.
*/
private String message;
/**
* The original type name of the JavaScript exception this class wraps,
* initialized as e.name.
*/
private String name;
/**
* @param e the object caught in JavaScript that triggered the exception
*/
public JavaScriptException(Object e) {
this(e, "");
}
/**
* @param e the object caught in JavaScript that triggered the exception
* @param description to include in getMessage(), e.g. at the top of a stack
* trace
*/
public JavaScriptException(Object e, String description) {
this.e = e;
this.description = description;
}
public JavaScriptException(String name, String description) {
this.message = "JavaScript " + name + " exception: " + description;
this.name = name;
this.description = description;
this.e = NOT_SET;
}
/**
* Used for testing instantiations.
*
* @param message the detail message
*/
protected JavaScriptException(String message) {
super(message);
this.message = this.description = message;
this.e = NOT_SET;
}
/**
* Returns {@code true} if a thrown object is not set for the exception.
*/
public boolean isThrownSet() {
return e != NOT_SET;
}
/**
* Returns the original thrown object from javascript; may be {@code null}.
*/
public Object getThrown() {
return e == NOT_SET ? null : e;
}
/**
* Returns the original JavaScript message of the exception; may be
* null.
*/
public String getDescription() {
ensureInit();
return description;
}
/**
* Returns the original JavaScript the exception; may be null.
*
* @deprecated deprecated in favor for {@link #getThrown()} and {@link #isThrownSet()}
*/
@Deprecated
public JavaScriptObject getException() {
return (e instanceof JavaScriptObject) ? (JavaScriptObject) e : null;
}
@Override
public String getMessage() {
ensureInit();
return message;
}
/**
* Returns the original JavaScript type name of the exception; may be
* null.
*/
public String getName() {
ensureInit();
return name;
}
private void ensureInit() {
if (message == null) {
Object exception = getThrown();
name = getExceptionName(exception);
description = description + ": " + getExceptionDescription(exception);
message = "(" + name + ") " + description;
}
}
}