Java tutorial
//////////////////////////////////////////////////////////////////////////////// // checkstyle: Checks Java source code for adherence to a set of rules. // Copyright (C) 2001-2015 the original author or authors. // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Lesser General Public // License as published by the Free Software Foundation; either // version 2.1 of the License, or (at your option) any later version. // // This library 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 // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public // License along with this library; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA //////////////////////////////////////////////////////////////////////////////// package com.puppycrawl.tools.checkstyle.api; import java.beans.PropertyDescriptor; import java.lang.reflect.InvocationTargetException; import java.util.Collection; import java.util.List; import java.util.Locale; import java.util.StringTokenizer; import org.apache.commons.beanutils.BeanUtilsBean; import org.apache.commons.beanutils.ConversionException; import org.apache.commons.beanutils.ConvertUtilsBean; import org.apache.commons.beanutils.Converter; import org.apache.commons.beanutils.PropertyUtils; import org.apache.commons.beanutils.PropertyUtilsBean; import org.apache.commons.beanutils.converters.ArrayConverter; import org.apache.commons.beanutils.converters.BooleanConverter; import org.apache.commons.beanutils.converters.ByteConverter; import org.apache.commons.beanutils.converters.CharacterConverter; import org.apache.commons.beanutils.converters.DoubleConverter; import org.apache.commons.beanutils.converters.FloatConverter; import org.apache.commons.beanutils.converters.IntegerConverter; import org.apache.commons.beanutils.converters.LongConverter; import org.apache.commons.beanutils.converters.ShortConverter; import com.google.common.collect.Lists; /** * A Java Bean that implements the component lifecycle interfaces by * calling the bean's setters for all configuration attributes. * @author lkuehne */ public class AutomaticBean implements Configurable, Contextualizable { /** The configuration of this bean. */ private Configuration configuration; /** * Creates a BeanUtilsBean that is configured to use * type converters that throw a ConversionException * instead of using the default value when something * goes wrong. * * @return a configured BeanUtilsBean */ private static BeanUtilsBean createBeanUtilsBean() { final ConvertUtilsBean cub = new ConvertUtilsBean(); cub.register(new BooleanConverter(), Boolean.TYPE); cub.register(new BooleanConverter(), Boolean.class); cub.register(new ArrayConverter(boolean[].class, new BooleanConverter()), boolean[].class); cub.register(new ByteConverter(), Byte.TYPE); cub.register(new ByteConverter(), Byte.class); cub.register(new ArrayConverter(byte[].class, new ByteConverter()), byte[].class); cub.register(new CharacterConverter(), Character.TYPE); cub.register(new CharacterConverter(), Character.class); cub.register(new ArrayConverter(char[].class, new CharacterConverter()), char[].class); cub.register(new DoubleConverter(), Double.TYPE); cub.register(new DoubleConverter(), Double.class); cub.register(new ArrayConverter(double[].class, new DoubleConverter()), double[].class); cub.register(new FloatConverter(), Float.TYPE); cub.register(new FloatConverter(), Float.class); cub.register(new ArrayConverter(float[].class, new FloatConverter()), float[].class); cub.register(new IntegerConverter(), Integer.TYPE); cub.register(new IntegerConverter(), Integer.class); cub.register(new ArrayConverter(int[].class, new IntegerConverter()), int[].class); cub.register(new LongConverter(), Long.TYPE); cub.register(new LongConverter(), Long.class); cub.register(new ArrayConverter(long[].class, new LongConverter()), long[].class); cub.register(new ShortConverter(), Short.TYPE); cub.register(new ShortConverter(), Short.class); cub.register(new ArrayConverter(short[].class, new ShortConverter()), short[].class); cub.register(new RelaxedStringArrayConverter(), String[].class); // BigDecimal, BigInteger, Class, Date, String, Time, TimeStamp // do not use defaults in the default configuration of ConvertUtilsBean return new BeanUtilsBean(cub, new PropertyUtilsBean()); } /** * Implements the Configurable interface using bean introspection. * * <p>Subclasses are allowed to add behaviour. After the bean * based setup has completed first the method * {@link #finishLocalSetup finishLocalSetup} * is called to allow completion of the bean's local setup, * after that the method {@link #setupChild setupChild} * is called for each {@link Configuration#getChildren child Configuration} * of {@code configuration}. * * @see Configurable */ @Override public final void configure(Configuration config) throws CheckstyleException { configuration = config; final String[] attributes = config.getAttributeNames(); for (final String key : attributes) { final String value = config.getAttribute(key); tryCopyProperty(config.getName(), key, value, true); } finishLocalSetup(); final Configuration[] childConfigs = config.getChildren(); for (final Configuration childConfig : childConfigs) { setupChild(childConfig); } } /** * Recheck property and try to copy it. * @param moduleName name of the module/class * @param key key of value * @param value value * @param recheck whether to check for property existence before copy * @throws CheckstyleException then property defined incorrectly */ private void tryCopyProperty(String moduleName, String key, Object value, boolean recheck) throws CheckstyleException { final BeanUtilsBean beanUtils = createBeanUtilsBean(); try { if (recheck) { // BeanUtilsBean.copyProperties silently ignores missing setters // for key, so we have to go through great lengths here to // figure out if the bean property really exists. final PropertyDescriptor descriptor = PropertyUtils.getPropertyDescriptor(this, key); if (descriptor == null) { final String message = String.format(Locale.ROOT, "Property '%s' in module %s " + "does not exist, please check the documentation", key, moduleName); throw new CheckstyleException(message); } } // finally we can set the bean property beanUtils.copyProperty(this, key, value); } catch (final InvocationTargetException | IllegalAccessException | NoSuchMethodException e) { // There is no way to catch IllegalAccessException | NoSuchMethodException // as we do PropertyUtils.getPropertyDescriptor before beanUtils.copyProperty // so we have to join these exceptions with InvocationTargetException // to satisfy UTs coverage final String message = String.format(Locale.ROOT, "Cannot set property '%s' to '%s' in module %s", key, value, moduleName); throw new CheckstyleException(message, e); } catch (final IllegalArgumentException | ConversionException e) { final String message = String.format(Locale.ROOT, "illegal value '%s' for property " + "'%s' of module %s", value, key, moduleName); throw new CheckstyleException(message, e); } } /** * Implements the Contextualizable interface using bean introspection. * @see Contextualizable */ @Override public final void contextualize(Context context) throws CheckstyleException { final Collection<String> attributes = context.getAttributeNames(); for (final String key : attributes) { final Object value = context.get(key); tryCopyProperty(getClass().getName(), key, value, false); } } /** * Returns the configuration that was used to configure this component. * @return the configuration that was used to configure this component. */ protected final Configuration getConfiguration() { return configuration; } /** * Provides a hook to finish the part of this component's setup that * was not handled by the bean introspection. * <p> * The default implementation does nothing. * </p> * @throws CheckstyleException if there is a configuration error. */ protected void finishLocalSetup() throws CheckstyleException { // No code by default, should be overridden only by demand at subclasses } /** * Called by configure() for every child of this component's Configuration. * <p> * The default implementation does nothing. * </p> * @param childConf a child of this component's Configuration * @throws CheckstyleException if there is a configuration error. * @see Configuration#getChildren */ protected void setupChild(Configuration childConf) throws CheckstyleException { // No code by default, should be overridden only by demand at subclasses } /** * A converter that does not care whether the array elements contain String * characters like '*' or '_'. The normal ArrayConverter class has problems * with this characters. */ private static class RelaxedStringArrayConverter implements Converter { @SuppressWarnings({ "unchecked", "rawtypes" }) @Override public Object convert(Class type, Object value) { // Convert to a String and trim it for the tokenizer. final StringTokenizer tokenizer = new StringTokenizer(value.toString().trim(), ","); final List<String> result = Lists.newArrayList(); while (tokenizer.hasMoreTokens()) { final String token = tokenizer.nextToken(); result.add(token.trim()); } return result.toArray(new String[result.size()]); } } }