Java tutorial
/* * Copyright (c) 2002-2015 JGoodies Software GmbH. All Rights Reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * o Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * o Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * o Neither the name of JGoodies Software GmbH nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package com.jgoodies.binding.beans; import static com.jgoodies.common.base.Preconditions.checkArgument; import static com.jgoodies.common.base.Preconditions.checkNotNull; import java.awt.Component; import java.beans.BeanInfo; import java.beans.Introspector; import java.beans.PropertyChangeListener; import java.beans.PropertyDescriptor; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import com.jgoodies.common.bean.ObservableBean; import com.jgoodies.common.bean.ObservableBean2; /** * Consists exclusively of static methods that provide * convenience behavior for working with Java Bean properties. * * @author Karsten Lentzsch * @version $Revision: 1.22 $ * * @see Introspector * @see BeanInfo * @see PropertyDescriptor */ public final class BeanUtils { private BeanUtils() { // Override default constructor; prevents instantiation. } /** * Checks and answers whether the given class supports bound properties, * i.e. it provides a pair of multicast event listener registration methods * for {@code PropertyChangeListener}s: * <pre> * public void addPropertyChangeListener(PropertyChangeListener x); * public void removePropertyChangeListener(PropertyChangeListener x); * </pre> * * @param clazz the class to test * @return true if the class supports bound properties, false otherwise */ public static boolean supportsBoundProperties(Class<?> clazz) { return getPCLAdder(clazz) != null && getPCLRemover(clazz) != null; } /** * Holds the class parameter list that is used to lookup * the adder and remover methods for PropertyChangeListeners. */ private static final Class<?>[] PCL_PARAMS = new Class<?>[] { PropertyChangeListener.class }; /** * Holds the class parameter list that is used to lookup * the adder and remover methods for PropertyChangeListeners. */ private static final Class<?>[] NAMED_PCL_PARAMS = new Class<?>[] { String.class, PropertyChangeListener.class }; /** * Looks up and returns the method that adds a multicast * PropertyChangeListener to instances of the given class. * * @param clazz the class that provides the adder method * @return the method that adds multicast PropertyChangeListeners */ public static Method getPCLAdder(Class<?> clazz) { try { return clazz.getMethod("addPropertyChangeListener", PCL_PARAMS); } catch (NoSuchMethodException e) { return null; } } /** * Looks up and returns the method that removes a multicast * PropertyChangeListener from instances of the given class. * * @param clazz the class that provides the remover method * @return the method that removes multicast PropertyChangeListeners */ public static Method getPCLRemover(Class<?> clazz) { try { return clazz.getMethod("removePropertyChangeListener", PCL_PARAMS); } catch (NoSuchMethodException e) { return null; } } /** * Looks up and returns the method that adds a PropertyChangeListener * for a specified property name to instances of the given class. * * @param clazz the class that provides the adder method * @return the method that adds the PropertyChangeListeners */ public static Method getNamedPCLAdder(Class<?> clazz) { try { return clazz.getMethod("addPropertyChangeListener", NAMED_PCL_PARAMS); } catch (NoSuchMethodException e) { return null; } } /** * Looks up and returns the method that removes a PropertyChangeListener * for a specified property name from instances of the given class. * * @param clazz the class that provides the remover method * @return the method that removes the PropertyChangeListeners */ public static Method getNamedPCLRemover(Class<?> clazz) { try { return clazz.getMethod("removePropertyChangeListener", NAMED_PCL_PARAMS); } catch (NoSuchMethodException e) { return null; } } /** * Adds a property change listener to the given bean. First checks * whether the bean supports <em>bound properties</em>, i.e. it provides * a pair of methods to register multicast property change event listeners; * see section 7.4.1 of the Java Beans specification for details.<p> * * {@code beanClass} can be a type other than {@code bean.getClass()}, * for example if the bean is specified by public interfaces, * and implemented by package private class. * * @param bean the bean to add the property change listener to * @param beanClass the Bean class used to lookup methods from * @param listener the listener to add * * @throws NullPointerException * if the bean or listener is {@code null} * @throws IllegalArgumentException * if the bean is not an instance of the bean class * @throws PropertyUnboundException * if the bean does not support bound properties * @throws PropertyNotBindableException * if the property change handler cannot be added successfully * * @since 1.1.1 */ public static void addPropertyChangeListener(Object bean, Class<?> beanClass, PropertyChangeListener listener) { checkNotNull(listener, "The listener must not be null."); if (beanClass == null) { beanClass = bean.getClass(); } else { checkArgument(beanClass.isInstance(bean), "The bean %s must be an instance of %s", bean, beanClass); } if (bean instanceof ObservableBean) { ((ObservableBean) bean).addPropertyChangeListener(listener); return; } if (bean instanceof Component) { ((Component) bean).addPropertyChangeListener(listener); return; } // Check whether the bean supports bound properties. if (!BeanUtils.supportsBoundProperties(beanClass)) { throw new PropertyUnboundException("Bound properties unsupported by bean class=" + beanClass + "\nThe Bean class must provide a pair of methods:" + "\npublic void addPropertyChangeListener(PropertyChangeListener x);" + "\npublic void removePropertyChangeListener(PropertyChangeListener x);"); } Method multicastPCLAdder = getPCLAdder(beanClass); try { multicastPCLAdder.invoke(bean, listener); } catch (InvocationTargetException e) { throw new PropertyNotBindableException("Due to an InvocationTargetException we failed to add " + "a multicast PropertyChangeListener to bean: " + bean, e.getCause()); } catch (IllegalAccessException e) { throw new PropertyNotBindableException("Due to an IllegalAccessException we failed to add " + "a multicast PropertyChangeListener to bean: " + bean, e); } } /** * Adds a named property change listener to the given bean. The bean * must provide the optional support for listening on named properties * as described in section 7.4.5 of the * <a href="http://java.sun.com/products/javabeans/docs/spec.html">Java Bean * Specification</a>. The bean class must provide the method: * <pre> * public void addPropertyChangeListener(String name, PropertyChangeListener l); * </pre><p> * * {@code beanClass} can be a type other than {@code bean.getClass()}, * for example if the bean is specified by public interfaces, * and implemented by package private class. * * @param bean the bean to add a property change handler * @param beanClass the Bean class used to lookup methods from * @param propertyName the name of the property to be observed * @param listener the listener to add * * @throws NullPointerException * if the bean, propertyName or listener is {@code null} * @throws IllegalArgumentException * if the bean is not an instance of the bean class * @throws PropertyNotBindableException * if the property change handler cannot be added successfully */ public static void addPropertyChangeListener(Object bean, Class<?> beanClass, String propertyName, PropertyChangeListener listener) { checkNotNull(propertyName, "The property name must not be null."); checkNotNull(listener, "The listener must not be null."); if (beanClass == null) { beanClass = bean.getClass(); } else { checkArgument(beanClass.isInstance(bean), "The bean %s must be an instance of %s", bean, beanClass); } if (bean instanceof ObservableBean2) { ((ObservableBean2) bean).addPropertyChangeListener(propertyName, listener); return; } if (bean instanceof Component) { ((Component) bean).addPropertyChangeListener(propertyName, listener); return; } Method namedPCLAdder = getNamedPCLAdder(beanClass); if (namedPCLAdder == null) { throw new PropertyNotBindableException("Could not find the bean method" + "\npublic void addPropertyChangeListener(String, PropertyChangeListener);" + "\nin bean: " + bean); } try { namedPCLAdder.invoke(bean, propertyName, listener); } catch (InvocationTargetException e) { throw new PropertyNotBindableException("Due to an InvocationTargetException we failed to add " + "a named PropertyChangeListener to bean: " + bean, e.getCause()); } catch (IllegalAccessException e) { throw new PropertyNotBindableException("Due to an IllegalAccessException we failed to add " + "a named PropertyChangeListener to bean: " + bean, e); } } /** * Adds a property change listener to the given bean. First checks * whether the bean supports <em>bound properties</em>, i.e. it provides * a pair of methods to register multicast property change event listeners; * see section 7.4.1 of the Java Beans specification for details. * * @param bean the bean to add the property change listener to * @param listener the listener to add * * @throws NullPointerException * if the bean or listener is {@code null} * @throws PropertyUnboundException * if the bean does not support bound properties * @throws PropertyNotBindableException * if the property change handler cannot be added successfully */ public static void addPropertyChangeListener(Object bean, PropertyChangeListener listener) { addPropertyChangeListener(bean, (Class<?>) null, listener); } /** * Adds a named property change listener to the given bean. The bean * must provide the optional support for listening on named properties * as described in section 7.4.5 of the * <a href="http://java.sun.com/products/javabeans/docs/spec.html">Java Bean * Specification</a>. The bean class must provide the method: * <pre> * public void addPropertyChangeListener(String name, PropertyChangeListener l); * </pre> * * @param bean the bean to add a property change handler * @param propertyName the name of the property to be observed * @param listener the listener to add * * @throws NullPointerException * if the bean, propertyName or listener is {@code null} * @throws PropertyNotBindableException * if the property change handler cannot be added successfully */ public static void addPropertyChangeListener(Object bean, String propertyName, PropertyChangeListener listener) { addPropertyChangeListener(bean, null, propertyName, listener); } /** * Removes a property change listener from the given bean.<p> * * {@code beanClass} can be a type other than {@code bean.getClass()}, * for example if the bean is specified by public interfaces, * and implemented by package private class. * * @param bean the bean to remove the property change listener from * @param beanClass the Java Bean class used to lookup methods from * @param listener the listener to remove * * @throws NullPointerException * if the bean or listener is {@code null} * @throws IllegalArgumentException * if the bean is not an instance of the bean class * @throws PropertyUnboundException * if the bean does not support bound properties * @throws PropertyNotBindableException * if the property change handler cannot be removed successfully * * @since 1.1.1 */ public static void removePropertyChangeListener(Object bean, Class<?> beanClass, PropertyChangeListener listener) { checkNotNull(listener, "The listener must not be null."); if (beanClass == null) { beanClass = bean.getClass(); } else { checkArgument(beanClass.isInstance(bean), "The bean %s must be an instance of %s", bean, beanClass); } if (bean instanceof ObservableBean) { ((ObservableBean) bean).removePropertyChangeListener(listener); return; } if (bean instanceof Component) { ((Component) bean).removePropertyChangeListener(listener); return; } Method multicastPCLRemover = getPCLRemover(beanClass); if (multicastPCLRemover == null) { throw new PropertyUnboundException("Could not find the method:" + "\npublic void removePropertyChangeListener(String, PropertyChangeListener x);" + "\nfor bean:" + bean); } try { multicastPCLRemover.invoke(bean, listener); } catch (InvocationTargetException e) { throw new PropertyNotBindableException("Due to an InvocationTargetException we failed to remove " + "a multicast PropertyChangeListener from bean: " + bean, e.getCause()); } catch (IllegalAccessException e) { throw new PropertyNotBindableException("Due to an IllegalAccessException we failed to remove " + "a multicast PropertyChangeListener from bean: " + bean, e); } } /** * Removes a named property change listener from the given bean. The bean * must provide the optional support for listening on named properties * as described in section 7.4.5 of the * <a href="http://java.sun.com/products/javabeans/docs/spec.html">Java Bean * Specification</a>. The bean class must provide the method: * <pre> * public void removePropertyChangeHandler(String name, PropertyChangeListener l); * </pre><p> * * {@code beanClass} can be a type other than {@code bean.getClass()}, * for example if the bean is specified by public interfaces, * and implemented by package private class. * * @param bean the bean to remove the property change listener from * @param beanClass the Java Bean class used to lookup methods from * @param propertyName the name of the observed property * @param listener the listener to remove * * @throws NullPointerException * if the bean, propertyName, or listener is {@code null} * @throws IllegalArgumentException * if the bean is not an instance of the bean class * @throws PropertyNotBindableException * if the property change handler cannot be removed successfully * * @since 1.1.1 */ public static void removePropertyChangeListener(Object bean, Class<?> beanClass, String propertyName, PropertyChangeListener listener) { checkNotNull(propertyName, "The property name must not be null."); checkNotNull(listener, "The listener must not be null."); if (beanClass == null) { beanClass = bean.getClass(); } else { checkArgument(beanClass.isInstance(bean), "The bean %s must be an instance of %s", bean, beanClass); } if (bean instanceof ObservableBean2) { ((ObservableBean2) bean).removePropertyChangeListener(propertyName, listener); return; } if (bean instanceof Component) { ((Component) bean).removePropertyChangeListener(propertyName, listener); return; } Method namedPCLRemover = getNamedPCLRemover(beanClass); if (namedPCLRemover == null) { throw new PropertyNotBindableException("Could not find the bean method" + "\npublic void removePropertyChangeListener(String, PropertyChangeListener);" + "\nin bean: " + bean); } try { namedPCLRemover.invoke(bean, propertyName, listener); } catch (InvocationTargetException e) { throw new PropertyNotBindableException("Due to an InvocationTargetException we failed to remove " + "a named PropertyChangeListener from bean: " + bean, e.getCause()); } catch (IllegalAccessException e) { throw new PropertyNotBindableException("Due to an IllegalAccessException we failed to remove " + "a named PropertyChangeListener from bean: " + bean, e); } } /** * Removes a property change listener from the given bean. * * @param bean the bean to remove the property change listener from * @param listener the listener to remove * @throws NullPointerException if the bean or listener is {@code null} * @throws PropertyUnboundException * if the bean does not support bound properties * @throws PropertyNotBindableException * if the property change handler cannot be removed successfully */ public static void removePropertyChangeListener(Object bean, PropertyChangeListener listener) { removePropertyChangeListener(bean, (Class<?>) null, listener); } /** * Removes a named property change listener from the given bean. The bean * must provide the optional support for listening on named properties * as described in section 7.4.5 of the * <a href="http://java.sun.com/products/javabeans/docs/spec.html">Java Bean * Specification</a>. The bean class must provide the method: * <pre> * public void removePropertyChangeHandler(String name, PropertyChangeListener l); * </pre><p> * * {@code beanClass} can be a type other than {@code bean.getClass()}, * for example if the bean is specified by public interfaces, * and implemented by package private class. * * @param bean the bean to remove the property change listener from * @param propertyName the name of the observed property * @param listener the listener to remove * @throws NullPointerException * if the bean, propertyName, or listener is {@code null} * @throws PropertyNotBindableException * if the property change handler cannot be removed successfully */ public static void removePropertyChangeListener(Object bean, String propertyName, PropertyChangeListener listener) { removePropertyChangeListener(bean, null, propertyName, listener); } }