com.aspose.words

Example:

Document doc = new Document();
    DocumentBuilder builder = new DocumentBuilder(doc);

    builder.getFont().setName("Times New Roman");
    builder.writeln("Hello world!");

    FontSubstitutionWarningCollector callback = new FontSubstitutionWarningCollector();
    doc.setWarningCallback(callback);

    // Store the current collection of font sources, which will be the default font source for every document
    // for which we do not specify a different font source.
    FontSourceBase[] originalFontSources = FontSettings.getDefaultInstance().getFontsSources();

    // For testing purposes, we will set Aspose.Words to look for fonts only in a folder that does not exist.
    FontSettings.getDefaultInstance().setFontsFolder("", false);

    // When rendering the document, there will be no place to find the "Times New Roman" font.
    // This will cause a font substitution warning, which our callback will detect.
    doc.save(getArtifactsDir() + "FontSettings.SubstitutionWarning.pdf");

    FontSettings.getDefaultInstance().setFontsSources(originalFontSources);

    Assert.assertTrue(callback.FontSubstitutionWarnings.get(0).getDescription()
            .equals("Font 'Times New Roman' has not been found. Using 'Fanwood' font instead. Reason: first available font."));
}

private static class FontSubstitutionWarningCollector implements IWarningCallback {
    /// <summary>
    /// Called every time a warning occurs during loading/saving.
    /// </summary>
    public void warning(WarningInfo info) {
        if (info.getWarningType() == WarningType.FONT_SUBSTITUTION)
            FontSubstitutionWarnings.warning(info);
    }

    public WarningInfoCollection FontSubstitutionWarnings = new WarningInfoCollection();
}

Example:

@Test
public void enableFontSubstitution() throws Exception {
    // Open a document that contains text formatted with a font that does not exist in any of our font sources.
    Document doc = new Document(getMyDir() + "Missing font.docx");

    // Assign a callback for handling font substitution warnings.
    HandleDocumentSubstitutionWarnings substitutionWarningHandler = new HandleDocumentSubstitutionWarnings();
    doc.setWarningCallback(substitutionWarningHandler);

    // Set a default font name and enable font substitution.
    FontSettings fontSettings = new FontSettings();
    fontSettings.getSubstitutionSettings().getDefaultFontSubstitution().setDefaultFontName("Arial");
    fontSettings.getSubstitutionSettings().getFontInfoSubstitution().setEnabled(true);

    // We will get a font substitution warning if we save a document with a missing font.
    doc.setFontSettings(fontSettings);
    doc.save(getArtifactsDir() + "FontSettings.EnableFontSubstitution.pdf");

    Iterator<WarningInfo> warnings = substitutionWarningHandler.FontWarnings.iterator();

    while (warnings.hasNext())
        System.out.println(warnings.next().getDescription());

    // We can also verify warnings in the collection and clear them.
    Assert.assertEquals(WarningSource.LAYOUT, substitutionWarningHandler.FontWarnings.get(0).getSource());
    Assert.assertEquals("Font '28 Days Later' has not been found. Using 'Calibri' font instead. Reason: alternative name from document.",
            substitutionWarningHandler.FontWarnings.get(0).getDescription());

    substitutionWarningHandler.FontWarnings.clear();

    Assert.assertTrue(substitutionWarningHandler.FontWarnings.getCount() == 0);
}

public static class HandleDocumentSubstitutionWarnings implements IWarningCallback {
    /// <summary>
    /// Called every time a warning occurs during loading/saving.
    /// </summary>
    public void warning(WarningInfo info) {
        if (info.getWarningType() == WarningType.FONT_SUBSTITUTION)
            FontWarnings.warning(info);
    }

    public WarningInfoCollection FontWarnings = new WarningInfoCollection();
}