Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.jdt.core; import java.io.PrintStream; import java.io.PrintWriter; import org.eclipse.core.runtime.CoreException; import org.eclipse.core.runtime.IStatus; import org.eclipse.jdt.internal.core.JavaModelStatus; /** * A checked exception representing a failure in the Java model. * Java model exceptions contain a Java-specific status object describing the * cause of the exception. * <p> * Instances of this class are automatically created by the Java model * when problems arise, so there is generally no need for clients to create * instances. * </p> * * @see IJavaModelStatus * @see IJavaModelStatusConstants * * @noextend This class is not intended to be subclassed by clients. */ public class JavaModelException extends CoreException { private static final long serialVersionUID = -760398656505871287L; // backward compatible CoreException nestedCoreException; /** * Creates a Java model exception that wrappers the given <code>Throwable</code>. * The exception contains a Java-specific status object with severity * <code>IStatus.ERROR</code> and the given status code. * * @param e the <code>Throwable</code> * @param code one of the Java-specific status codes declared in * <code>IJavaModelStatusConstants</code> * @see IJavaModelStatusConstants * @see org.eclipse.core.runtime.IStatus#ERROR */ public JavaModelException(Throwable e, int code) { this(new JavaModelStatus(code, e)); } /** * Creates a Java model exception for the given <code>CoreException</code>. * Equivalent to * <code>JavaModelException(exception,IJavaModelStatusConstants.CORE_EXCEPTION</code>. * * @param exception the <code>CoreException</code> */ public JavaModelException(CoreException exception) { super(exception.getStatus()); this.nestedCoreException = exception; } /** * Creates a Java model exception for the given Java-specific status object. * * @param status the Java-specific status object */ public JavaModelException(IJavaModelStatus status) { super(status); } /** * Creates a Java model exception for the given status object. * * @since 3.14 */ public JavaModelException(IStatus status) { super(status); } /** * Returns the underlying <code>Throwable</code> that caused the failure. * * @return the wrapped <code>Throwable</code>, or <code>null</code> if the * direct case of the failure was at the Java model layer */ public Throwable getException() { if (this.nestedCoreException == null) { return getStatus().getException(); } else { return this.nestedCoreException; } } /** * Returns the Java model status object for this exception. * Equivalent to <code>(IJavaModelStatus) getStatus()</code>. * * @return a status object */ public IJavaModelStatus getJavaModelStatus() { IStatus status = getStatus(); if (status instanceof IJavaModelStatus) { return (IJavaModelStatus) status; } else { // A regular IStatus is created only in the case of a CoreException. // See bug 13492 Should handle JavaModelExceptions that contains CoreException more gracefully return new JavaModelStatus(this.nestedCoreException); } } /** * Returns whether this exception indicates that a Java model element does not * exist. Such exceptions have a status with a code of * <code>IJavaModelStatusConstants.ELEMENT_DOES_NOT_EXIST</code> or * <code>IJavaModelStatusConstants.ELEMENT_NOT_ON_CLASSPATH</code>. * This is a convenience method. * * @return <code>true</code> if this exception indicates that a Java model * element does not exist * @see IJavaModelStatus#isDoesNotExist() * @see IJavaModelStatusConstants#ELEMENT_DOES_NOT_EXIST * @see IJavaModelStatusConstants#ELEMENT_NOT_ON_CLASSPATH */ public boolean isDoesNotExist() { IJavaModelStatus javaModelStatus = getJavaModelStatus(); return javaModelStatus != null && javaModelStatus.isDoesNotExist(); } /** * Prints this exception's stack trace to the given print stream. * * @param output the print stream * @since 3.0 */ @Override public void printStackTrace(PrintStream output) { synchronized (output) { super.printStackTrace(output); Throwable throwable = getException(); if (throwable != null) { output.print("Caused by: "); //$NON-NLS-1$ throwable.printStackTrace(output); } } } /** * Prints this exception's stack trace to the given print writer. * * @param output the print writer * @since 3.0 */ @Override public void printStackTrace(PrintWriter output) { synchronized (output) { super.printStackTrace(output); Throwable throwable = getException(); if (throwable != null) { output.print("Caused by: "); //$NON-NLS-1$ throwable.printStackTrace(output); } } } /* * Returns a printable representation of this exception suitable for debugging * purposes only. */ @Override public String toString() { StringBuffer buffer = new StringBuffer(); buffer.append("Java Model Exception: "); //$NON-NLS-1$ if (getException() != null) { if (getException() instanceof CoreException) { CoreException c = (CoreException) getException(); buffer.append("Core Exception [code "); //$NON-NLS-1$ buffer.append(c.getStatus().getCode()); buffer.append("] "); //$NON-NLS-1$ buffer.append(c.getStatus().getMessage()); } else { buffer.append(getException().toString()); } } else { buffer.append(getStatus().toString()); } return buffer.toString(); } }