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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package jdk.nashorn.api.scripting;

import java.util.ArrayList;
import java.util.List;
import jdk.nashorn.internal.codegen.CompilerConstants;
import jdk.nashorn.internal.runtime.ECMAErrors;
import jdk.nashorn.internal.runtime.ScriptObject;

This is base exception for all Nashorn exceptions. These originate from
user's ECMAScript code. Example: script parse errors, exceptions thrown from
scripts. Note that ScriptEngine methods like "eval", "invokeMethod",
"invokeFunction" will wrap this as ScriptException and throw it. But, there
are cases where user may need to access this exception (or implementation
defined subtype of this). For example, if java interface is implemented by a
script object or Java access to script object properties via java.util.Map
interface. In these cases, user code will get an instance of this or
implementation defined subclass.
Since:
1.8u40/**
 * This is base exception for all Nashorn exceptions. These originate from
 * user's ECMAScript code. Example: script parse errors, exceptions thrown from
 * scripts. Note that ScriptEngine methods like "eval", "invokeMethod",
 * "invokeFunction" will wrap this as ScriptException and throw it. But, there
 * are cases where user may need to access this exception (or implementation
 * defined subtype of this). For example, if java interface is implemented by a
 * script object or Java access to script object properties via java.util.Map
 * interface. In these cases, user code will get an instance of this or
 * implementation defined subclass.
 *
 * @since 1.8u40
 */
@SuppressWarnings("serial")
public abstract class NashornException extends RuntimeException {
    private static final long serialVersionUID = 1L;

    // script file name
    private String fileName;
    // script line number
    private int line;
    // are the line and fileName unknown?
    private boolean lineAndFileNameUnknown;
    // script column number
    private int column;
    // underlying ECMA error object - lazily initialized
    private Object ecmaError;

    
Constructor to initialize error message, file name, line and column numbers.
Params:
msg –       exception message
fileName –  file name
line –      line number
column –    column number/**
     * Constructor to initialize error message, file name, line and column numbers.
     *
     * @param msg       exception message
     * @param fileName  file name
     * @param line      line number
     * @param column    column number
     */
    protected NashornException(final String msg, final String fileName, final int line, final int column) {
        this(msg, null, fileName, line, column);
    }

    
Constructor to initialize error message, cause exception, file name, line and column numbers.
Params:
msg –       exception message
cause –     exception cause
fileName –  file name
line –      line number
column –    column number/**
     * Constructor to initialize error message, cause exception, file name, line and column numbers.
     *
     * @param msg       exception message
     * @param cause     exception cause
     * @param fileName  file name
     * @param line      line number
     * @param column    column number
     */
    protected NashornException(final String msg, final Throwable cause, final String fileName, final int line, final int column) {
        super(msg, cause == null ? null : cause);
        this.fileName = fileName;
        this.line = line;
        this.column = column;
    }

    
Constructor to initialize error message and cause exception.
Params:
msg –       exception message
cause –     exception cause/**
     * Constructor to initialize error message and cause exception.
     *
     * @param msg       exception message
     * @param cause     exception cause
     */
    protected NashornException(final String msg, final Throwable cause) {
        super(msg, cause == null ? null : cause);
        // Hard luck - no column number info
        this.column = -1;
        // We can retrieve the line number and file name from the stack trace if needed
        this.lineAndFileNameUnknown = true;
    }

    
Get the source file name for this NashornException 
Returns:
the file name/**
     * Get the source file name for this {@code NashornException}
     *
     * @return the file name
     */
    public final String getFileName() {
        ensureLineAndFileName();
        return fileName;
    }

    
Set the source file name for this NashornException 
Params:
fileName – the file name/**
     * Set the source file name for this {@code NashornException}
     *
     * @param fileName the file name
     */
    public final void setFileName(final String fileName) {
        this.fileName = fileName;
        lineAndFileNameUnknown = false;
    }

    
Get the line number for this NashornException 
Returns:
the line number/**
     * Get the line number for this {@code NashornException}
     *
     * @return the line number
     */
    public final int getLineNumber() {
        ensureLineAndFileName();
        return line;
    }

    
Set the line number for this NashornException 
Params:
line – the line number/**
     * Set the line number for this {@code NashornException}
     *
     * @param line the line number
     */
    public final void setLineNumber(final int line) {
        lineAndFileNameUnknown = false;
        this.line = line;
    }

    
Get the column for this NashornException 
Returns:
the column number/**
     * Get the column for this {@code NashornException}
     *
     * @return the column number
     */
    public final int getColumnNumber() {
        return column;
    }

    
Set the column for this NashornException 
Params:
column – the column number/**
     * Set the column for this {@code NashornException}
     *
     * @param column the column number
     */
    public final void setColumnNumber(final int column) {
        this.column = column;
    }

    
Returns array javascript stack frames from the given exception object.
Params:
exception – exception from which stack frames are retrieved and filtered
Returns:
array of javascript stack frames/**
     * Returns array javascript stack frames from the given exception object.
     *
     * @param exception exception from which stack frames are retrieved and filtered
     * @return array of javascript stack frames
     */
    public static StackTraceElement[] getScriptFrames(final Throwable exception) {
        final StackTraceElement[] frames = exception.getStackTrace();
        final List<StackTraceElement> filtered = new ArrayList<>();
        for (final StackTraceElement st : frames) {
            if (ECMAErrors.isScriptFrame(st)) {
                final String className = "<" + st.getFileName() + ">";
                String methodName = st.getMethodName();
                if (methodName.equals(CompilerConstants.PROGRAM.symbolName())) {
                    methodName = "<program>";
                } else {
                    methodName = stripMethodName(methodName);
                }

                filtered.add(new StackTraceElement(className, methodName,
                        st.getFileName(), st.getLineNumber()));
            }
        }
        return filtered.toArray(new StackTraceElement[0]);
    }

    private static String stripMethodName(final String methodName) {
        String name = methodName;

        final int nestedSeparator = name.lastIndexOf(CompilerConstants.NESTED_FUNCTION_SEPARATOR.symbolName());
        if (nestedSeparator >= 0) {
            name = name.substring(nestedSeparator + 1);
        }

        final int idSeparator = name.indexOf(CompilerConstants.ID_FUNCTION_SEPARATOR.symbolName());
        if (idSeparator >= 0) {
            name = name.substring(0, idSeparator);
        }

        return name.contains(CompilerConstants.ANON_FUNCTION_PREFIX.symbolName()) ? "<anonymous>" : name;
    }

    
Return a formatted script stack trace string with frames information separated by '\n'
Params:
exception – exception for which script stack string is returned
Returns:
formatted stack trace string/**
     * Return a formatted script stack trace string with frames information separated by '\n'
     *
     * @param exception exception for which script stack string is returned
     * @return formatted stack trace string
     */
    public static String getScriptStackString(final Throwable exception) {
        final StringBuilder buf = new StringBuilder();
        final StackTraceElement[] frames = getScriptFrames(exception);
        for (final StackTraceElement st : frames) {
            buf.append("\tat ");
            buf.append(st.getMethodName());
            buf.append(" (");
            buf.append(st.getFileName());
            buf.append(':');
            buf.append(st.getLineNumber());
            buf.append(")\n");
        }
        final int len = buf.length();
        // remove trailing '\n'
        if (len > 0) {
            assert buf.charAt(len - 1) == '\n';
            buf.deleteCharAt(len - 1);
        }
        return buf.toString();
    }

    
Get the thrown object. Subclass responsibility
Returns:
thrown object/**
     * Get the thrown object. Subclass responsibility
     * @return thrown object
     */
    protected Object getThrown() {
        return null;
    }

    
Initialization function for ECMA errors. Stores the error
in the ecmaError field of this class. It is only initialized
once, and then reused
Params:
global – the global
Returns:
initialized exception/**
     * Initialization function for ECMA errors. Stores the error
     * in the ecmaError field of this class. It is only initialized
     * once, and then reused
     *
     * @param global the global
     * @return initialized exception
     */
    NashornException initEcmaError(final ScriptObject global) {
        if (ecmaError != null) {
            return this; // initialized already!
        }

        final Object thrown = getThrown();
        if (thrown instanceof ScriptObject) {
            setEcmaError(ScriptObjectMirror.wrap(thrown, global));
        } else {
            setEcmaError(thrown);
        }

        return this;
    }

    
Return the underlying ECMA error object, if available.
Returns:
underlying ECMA Error object's mirror or whatever was thrown
        from script such as a String, Number or a Boolean./**
     * Return the underlying ECMA error object, if available.
     *
     * @return underlying ECMA Error object's mirror or whatever was thrown
     *         from script such as a String, Number or a Boolean.
     */
    public Object getEcmaError() {
        return ecmaError;
    }

    
Return the underlying ECMA error object, if available.
Params:
ecmaError – underlying ECMA Error object's mirror or whatever was thrown
        from script such as a String, Number or a Boolean./**
     * Return the underlying ECMA error object, if available.
     *
     * @param ecmaError underlying ECMA Error object's mirror or whatever was thrown
     *         from script such as a String, Number or a Boolean.
     */
    public void setEcmaError(final Object ecmaError) {
        this.ecmaError = ecmaError;
    }

    private void ensureLineAndFileName() {
        if (lineAndFileNameUnknown) {
            for (final StackTraceElement ste : getStackTrace()) {
                if (ECMAErrors.isScriptFrame(ste)) {
                    // Whatever here is compiled from JavaScript code
                    fileName = ste.getFileName();
                    line = ste.getLineNumber();
                    return;
                }
            }

            lineAndFileNameUnknown = false;
        }
    }
}