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Add and use a configuration class for feature flags.
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src/main/java/net/coobird/thumbnailator/util/Configurations.java
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| package net.coobird.thumbnailator.util; | ||
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| import java.io.IOException; | ||
| import java.io.InputStream; | ||
| import java.util.Properties; | ||
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| /** | ||
| * This enum lists properties that affect the behavior of Thumbnailator. | ||
| * Most are used for enabling or disabling workarounds. | ||
| * | ||
| * <h2>Implementation note</h2> | ||
| * The values for properties listed here will be read from the system | ||
| * properties via {@link System#getProperty(String)}, therefore, can be set | ||
| * via the {@code -D} options when invoking the JVM. | ||
| * Alternatively, they can be included in {@code thumbnailator.properties} | ||
| * on the classpath (of the current thread's class loader.) | ||
| * | ||
| * <h2>Disclaimer</h2> | ||
| * Properties listed here are not part of Thumbnailator's public API. | ||
| * Therefore, code invoking Thumbnailator should not depend on these | ||
| * workarounds always being present. | ||
| */ | ||
| public enum Configurations { | ||
| /** | ||
| * Disables the Exif workaround. | ||
| * (<a href="https://github.com/coobird/thumbnailator/issues/108">Issue #108</a>) | ||
| * <br> | ||
| * Property name: {@code thumbnailator.disableExifWorkaround} | ||
| * <p> | ||
| * The default JPEG reader bundled with the JRE cannot handle JPEG images | ||
| * that doesn't have a JFIF APP0 marker segment as the first one. | ||
| * Some JPEG images have Exif (APP1) as the first one. | ||
| * <p> | ||
| * A workaround was introduced to resolve issue #108 by capturing the | ||
| * Exif data from the bitstream rather than relying on the JPEG reader. | ||
| * <p> | ||
| * Disabling this workaround will prevent Thumbnailator from properly | ||
| * identifying the image orientation of JPEG images which have Exif as | ||
| * the first marker. | ||
| * Therefore, unless the default behavior causes issues, disabling this | ||
| * workaround is not recommended. | ||
| */ | ||
| DISABLE_EXIF_WORKAROUND("thumbnailator.disableExifWorkaround"), | ||
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| /** | ||
| * Enable debug logging to standard error. | ||
| * This will enable debug logging throughout Thumbnailator. | ||
| * <br> | ||
| * Property name: {@code thumbnailator.debugLog} | ||
| */ | ||
| DEBUG_LOG("thumbnailator.debugLog"), | ||
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| /** | ||
| * Enable debug logging (to standard error) specifically for the | ||
| * {@link #DISABLE_EXIF_WORKAROUND Exif workaround}. | ||
| * <br> | ||
| * Property name: {@code thumbnailator.debugLog.exifWorkaround} | ||
| */ | ||
| DEBUG_LOG_EXIF_WORKAROUND("thumbnailator.debugLog.exifWorkaround"), | ||
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| /** | ||
| * Enable a workaround to conserve memory when handling large image files. | ||
| * (<a href="https://github.com/coobird/thumbnailator/issues/69">Issue #69</a>) | ||
| * <p> | ||
| * It is known that {@link OutOfMemoryError}s can occur when handling | ||
| * large images in Thumbnailator. | ||
| * <p> | ||
| * To fundamentally address the issue requires some dramatic design changes | ||
| * to the core parts of Thumbnailator which would take some time and would | ||
| * affect many internal parts of the library. | ||
| * Such changes would take time before being implemented, a workaround has | ||
| * been implemented in Thumbnailator 0.4.8 to reduce the likeliness of | ||
| * {@code OutOfMemoryError}s. | ||
| * <p> | ||
| * The workaround is not enabled by default, as it can negatively affect | ||
| * the quality of the final image. It has also not been extensively | ||
| * tested and will not necessarily prevent {@code OutOfMemoryError}s. | ||
| * <p> | ||
| * When the workaround enabled, a smaller version of the source image will | ||
| * be used to reduce memory usage, under the following conditions: | ||
| * <ul> | ||
| * <li>Both height and width have dimensions larger than 1800 pixels</li> | ||
| * <li>The expected memory size of the source image will take up more | ||
| * than 1/4 of the available JVM free memory</li> | ||
| * </ul> | ||
| */ | ||
| CONSERVE_MEMORY_WORKAROUND("thumbnailator.conserveMemoryWorkaround") | ||
| ; | ||
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| private final String key; | ||
| private static final Properties properties; | ||
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| static { | ||
| properties = new Properties(); | ||
| init(); | ||
| } | ||
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| /** | ||
| * This method will initialize configurations from | ||
| * {@code thumbnailator.properties} on the classpath. | ||
| * <p> | ||
| * Implementation note: {@code thumbnailator.properties} is searched from | ||
| * the class loader associated with the current | ||
| * thread, rather than the system class loader. | ||
| * <p> | ||
| * This is intended only to be called from tests. | ||
| */ | ||
| static void init() { | ||
| properties.clear(); | ||
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| InputStream resourceIs = Thread.currentThread() | ||
| .getContextClassLoader() | ||
| .getResourceAsStream("thumbnailator.properties"); | ||
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| if (resourceIs != null) { | ||
| try { | ||
| properties.load(resourceIs); | ||
| resourceIs.close(); | ||
| } catch (IOException e) { | ||
| throw new RuntimeException("Error while reading thumbnailator.properties", e); | ||
| } | ||
| } | ||
| } | ||
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| /** | ||
| * Clears the internal cache of properties. | ||
| * <p> | ||
| * This is intended only to be called from tests. | ||
| */ | ||
| static void clear() { | ||
| properties.clear(); | ||
| } | ||
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| Configurations(String key) { | ||
| this.key = key; | ||
| } | ||
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| /** | ||
| * Returns whether the specified configuration is enabled or not. | ||
| * @return {@code true} if the configuration is enabled, {@code false} | ||
| * otherwise. | ||
| */ | ||
| public boolean getBoolean() { | ||
| String propertyValue = properties.getProperty(key); | ||
| if (propertyValue != null) { | ||
| return Boolean.parseBoolean(propertyValue); | ||
| } | ||
| return Boolean.getBoolean(key); | ||
| } | ||
| } |
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src/test/java/net/coobird/thumbnailator/util/ConfigurationsTest.java
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| package net.coobird.thumbnailator.util; | ||
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| import org.junit.*; | ||
| import org.junit.experimental.runners.Enclosed; | ||
| import org.junit.runner.RunWith; | ||
| import org.junit.runner.notification.RunNotifier; | ||
| import org.junit.runners.BlockJUnit4ClassRunner; | ||
| import org.junit.runners.model.InitializationError; | ||
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| import java.net.URL; | ||
| import java.net.URLClassLoader; | ||
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| import static org.junit.Assert.assertFalse; | ||
| import static org.junit.Assert.assertTrue; | ||
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| @RunWith(Enclosed.class) | ||
| public class ConfigurationsTest { | ||
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| @Ignore | ||
| private static class Base { | ||
| @Before | ||
| public void resetConfiguration() { | ||
| Configurations.init(); | ||
| } | ||
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| @AfterClass | ||
| public static void clearConfiguration() { | ||
| Configurations.clear(); | ||
| } | ||
| } | ||
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| @RunWith(AllTruePropertiesTest.CustomRunner.class) | ||
| public static class AllTruePropertiesTest extends Base { | ||
| @Test | ||
| public void test() { | ||
| for (Configurations config : Configurations.values()) { | ||
| assertTrue(config.getBoolean()); | ||
| } | ||
| } | ||
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| public static class CustomRunner extends ThreadContextClassLoaderReplacingClassRunner { | ||
| public CustomRunner(Class<?> testClass) throws InitializationError { | ||
| super(testClass); | ||
| } | ||
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| protected ClassLoader getCustomClassLoader() { | ||
| return new PropertiesFileRedirectingClassLoader("Configurations/all_true.txt"); | ||
| } | ||
| } | ||
| } | ||
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| @RunWith(AllFalsePropertiesTest.CustomRunner.class) | ||
| public static class AllFalsePropertiesTest extends Base { | ||
| @Test | ||
| public void test() { | ||
| for (Configurations config : Configurations.values()) { | ||
| assertFalse(config.getBoolean()); | ||
| } | ||
| } | ||
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| public static class CustomRunner extends ThreadContextClassLoaderReplacingClassRunner { | ||
| public CustomRunner(Class<?> testClass) throws InitializationError { | ||
| super(testClass); | ||
| } | ||
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| protected ClassLoader getCustomClassLoader() { | ||
| return new PropertiesFileRedirectingClassLoader("Configurations/all_false.txt"); | ||
| } | ||
| } | ||
| } | ||
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| public abstract static class ThreadContextClassLoaderReplacingClassRunner extends BlockJUnit4ClassRunner { | ||
| public ThreadContextClassLoaderReplacingClassRunner(Class<?> testClass) throws InitializationError { | ||
| super(testClass); | ||
| } | ||
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| protected abstract ClassLoader getCustomClassLoader(); | ||
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| @Override | ||
| public void run(RunNotifier notifier) { | ||
| Thread.currentThread().setContextClassLoader(getCustomClassLoader()); | ||
| super.run(notifier); | ||
| Thread.currentThread().setContextClassLoader(ClassLoader.getSystemClassLoader()); | ||
| } | ||
| } | ||
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| @Ignore | ||
| public static class PropertiesFileRedirectingClassLoader extends URLClassLoader { | ||
| private final String resourceForPropertiesFile; | ||
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| public PropertiesFileRedirectingClassLoader(String resourceForPropertiesFile) { | ||
| super(new URL[] {}); | ||
| this.resourceForPropertiesFile = resourceForPropertiesFile; | ||
| } | ||
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| @Override | ||
| public URL getResource(String name) { | ||
| if (name.startsWith("thumbnailator.properties")) { | ||
| return ClassLoader.getSystemClassLoader().getResource(resourceForPropertiesFile); | ||
| } | ||
| return super.getResource(name); | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,4 @@ | ||
| thumbnailator.disableExifWorkaround=false | ||
| thumbnailator.debugLog=false | ||
| thumbnailator.debugLog.exifWorkaround=false | ||
| thumbnailator.conserveMemoryWorkaround=false |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,4 @@ | ||
| thumbnailator.disableExifWorkaround=true | ||
| thumbnailator.debugLog=true | ||
| thumbnailator.debugLog.exifWorkaround=true | ||
| thumbnailator.conserveMemoryWorkaround=true |