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Handlers may throw raw exceptions
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This adjusts the API to allow handlers to throw raw Exception
values. The Exception values will be caught and a useful parse error
will result (with the correct line/column numbers).

This also removes the recent leaf element handler as similar
functionality already existed.

Affects: #2
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@io7m
io7m committed Oct 24, 2020
1 parent 0ca01a2 commit 43a61da
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Showing 14 changed files with 78 additions and 197 deletions.
5 changes: 2 additions & 3 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTAttributesHandlerType.java
View file
Expand Up @@ -18,7 +18,6 @@
package com.io7m.blackthorne.api;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
* A function that, given a set of attributes, returns a {@code T}.
Expand All @@ -36,11 +35,11 @@ public interface BTAttributesHandlerType<T>
*
* @return A value of {@code T}
*
* @throws SAXException On errors
* @throws Exception On errors
*/

T parse(
BTElementParsingContextType context,
Attributes attributes)
throws SAXException;
throws Exception;
}
6 changes: 2 additions & 4 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTCharacterHandlerType.java
View file
Expand Up @@ -17,8 +17,6 @@

package com.io7m.blackthorne.api;

import org.xml.sax.SAXException;

/**
* A function that, given a string, returns a {@code T}.
*
Expand All @@ -37,13 +35,13 @@ public interface BTCharacterHandlerType<T>
*
* @return A value of {@code T}
*
* @throws SAXException On errors
* @throws Exception On errors
*/

T parse(
BTElementParsingContextType context,
char[] characters,
int offset,
int length)
throws SAXException;
throws Exception;
}
52 changes: 31 additions & 21 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTContentHandler.java
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Expand Up @@ -17,19 +17,20 @@
package com.io7m.blackthorne.api;

import com.io7m.jlexing.core.LexicalPosition;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Consumer;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.ext.DefaultHandler2;
import org.xml.sax.ext.Locator2;

import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Consumer;

/**
* A dispatching handler that produces values of type {@code T}. The handler is responsible for
* instantiating a content handler based on the received document namespace URI.
Expand Down Expand Up @@ -95,6 +96,18 @@ public static <U> BTContentHandlerBuilderType<U> builder(
return new Builder<>();
}

private static String messageOrException(
final Exception e)
{
final var messageOrNull = e.getMessage();
if (messageOrNull == null) {
return String.format(
"No error message provided for exception %s",
e.getClass().getName());
}
return messageOrNull;
}

@Override
public void setDocumentLocator(
final Locator in_locator)
Expand All @@ -109,12 +122,13 @@ public void startElement(
final String localName,
final String qualifiedName,
final Attributes attributes)
throws SAXException
{
try {
this.stackHandler.onElementStarted(namespaceURI, localName, attributes);
} catch (final SAXParseException e) {
this.error(e);
} catch (final Exception e) {
this.error(this.saxParseExceptionOf(e));
}
}

Expand All @@ -123,12 +137,13 @@ public void endElement(
final String namespaceURI,
final String localName,
final String qualifiedName)
throws SAXException
{
try {
this.stackHandler.onElementFinished(namespaceURI, localName);
} catch (final SAXParseException e) {
this.error(e);
} catch (final Exception e) {
this.error(this.saxParseExceptionOf(e));
}
}

Expand All @@ -137,12 +152,13 @@ public void characters(
final char[] ch,
final int start,
final int length)
throws SAXException
{
try {
this.stackHandler.onCharacters(ch, start, length);
} catch (final SAXParseException e) {
this.error(e);
} catch (final Exception e) {
this.error(this.saxParseExceptionOf(e));
}
}

Expand Down Expand Up @@ -189,18 +205,6 @@ public void fatalError(
throw e;
}

private static String messageOrException(
final Exception e)
{
final var messageOrNull = e.getMessage();
if (messageOrNull == null) {
return String.format(
"No error message provided for exception %s",
e.getClass().getName());
}
return messageOrNull;
}

private LexicalPosition<URI> currentLexical()
{
final LexicalPosition<URI> lexicalPosition;
Expand All @@ -223,6 +227,12 @@ private LexicalPosition<URI> currentLexical()
return lexicalPosition;
}

private SAXParseException saxParseExceptionOf(
final Exception e)
{
return new SAXParseException(e.getLocalizedMessage(), this.locator, e);
}

/**
* @return The parsed value
*/
Expand Down
4 changes: 3 additions & 1 deletion ...m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTContentHandlerBuilderType.java
View file
Expand Up @@ -55,7 +55,9 @@ default BTContentHandlerBuilderType<T> addHandler(
final String localName,
final BTElementHandlerConstructorType<?, T> constructor)
{
return this.addHandler(BTQualifiedName.of(namespaceURI, localName), constructor);
return this.addHandler(
BTQualifiedName.of(namespaceURI, localName),
constructor);
}

/**
Expand Down
6 changes: 2 additions & 4 deletions ...ackthorne.api/src/main/java/com/io7m/blackthorne/api/BTElementHandlerConstructorType.java
View file
Expand Up @@ -16,8 +16,6 @@

package com.io7m.blackthorne.api;

import org.xml.sax.SAXException;

/**
* A content handler constructor that produces handlers that produce values of type {@code A}
*
Expand All @@ -34,11 +32,11 @@ public interface BTElementHandlerConstructorType<CT, RT>
*
* @return A new content handler
*
* @throws SAXException If required
* @throws Exception If required
* @see BTElementParsingContextType#parseException(Exception)
*/

BTElementHandlerType<? extends CT, ? extends RT> create(
BTElementParsingContextType context)
throws SAXException;
throws Exception;
}
17 changes: 8 additions & 9 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTElementHandlerType.java
View file
Expand Up @@ -18,7 +18,6 @@
package com.io7m.blackthorne.api;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

import java.util.Map;
import java.util.function.Function;
Expand Down Expand Up @@ -82,13 +81,13 @@ default BTIgnoreUnrecognizedElements onShouldIgnoreUnrecognizedElements(
* @param context The parsing context
* @param attributes The element's attributes
*
* @throws SAXException On parse errors
* @throws Exception On parse errors
*/

default void onElementStart(
final BTElementParsingContextType context,
final Attributes attributes)
throws SAXException
throws Exception
{

}
Expand All @@ -101,25 +100,25 @@ default void onElementStart(
*
* @return The value produced by all of the data received up to this point
*
* @throws SAXException On parse errors
* @throws Exception On parse errors
*/

RT onElementFinished(BTElementParsingContextType context)
throws SAXException;
throws Exception;

/**
* A child element has been parsed successfully and produced a result.
*
* @param context The parsing context
* @param result The value produced by the child element
*
* @throws SAXException On parse errors
* @throws Exception On parse errors
*/

default void onChildValueProduced(
final BTElementParsingContextType context,
final CT result)
throws SAXException
throws Exception
{

}
Expand All @@ -132,15 +131,15 @@ default void onChildValueProduced(
* @param offset The start of the data within {@code data}
* @param length The length of the data within {@code data}
*
* @throws SAXException On parse errors
* @throws Exception On parse errors
*/

default void onCharacters(
final BTElementParsingContextType context,
final char[] data,
final int offset,
final int length)
throws SAXException
throws Exception
{

}
Expand Down
18 changes: 9 additions & 9 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTException.java
View file
Expand Up @@ -27,15 +27,6 @@ public final class BTException extends Exception
{
private final List<BTParseError> errors;

/**
* @return The parse errors encountered during parsing
*/

public List<BTParseError> errors()
{
return this.errors;
}

/**
* Construct an exception.
*
Expand Down Expand Up @@ -84,4 +75,13 @@ public BTException(
super(Objects.requireNonNull(inCause, "cause"));
this.errors = Objects.requireNonNull(inErrors, "errors");
}

/**
* @return The parse errors encountered during parsing
*/

public List<BTParseError> errors()
{
return this.errors;
}
}
9 changes: 4 additions & 5 deletions com.io7m.blackthorne.api/src/main/java/com/io7m/blackthorne/api/BTFunctorHandler.java
View file
Expand Up @@ -18,7 +18,6 @@
package com.io7m.blackthorne.api;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

import java.util.Map;
import java.util.Objects;
Expand Down Expand Up @@ -76,7 +75,7 @@ public BTIgnoreUnrecognizedElements onShouldIgnoreUnrecognizedElements(
public void onElementStart(
final BTElementParsingContextType context,
final Attributes attributes)
throws SAXException
throws Exception
{
this.handler.onElementStart(context, attributes);
}
Expand All @@ -85,7 +84,7 @@ public void onElementStart(
public void onChildValueProduced(
final BTElementParsingContextType context,
final A result)
throws SAXException
throws Exception
{
this.handler.onChildValueProduced(context, result);
}
Expand All @@ -96,14 +95,14 @@ public void onCharacters(
final char[] data,
final int offset,
final int length)
throws SAXException
throws Exception
{
this.handler.onCharacters(context, data, offset, length);
}

@Override
public C onElementFinished(final BTElementParsingContextType context)
throws SAXException
throws Exception
{
return this.function.apply(this.handler.onElementFinished(context));
}
Expand Down

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