com.sun.javafx.property.PropertyReference Maven / Gradle / Ivy
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package com.sun.javafx.property;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import javafx.beans.property.ReadOnlyProperty;
import com.sun.javafx.reflect.ReflectUtil;
/**
* A handle to a specific property defined on some {@link Bean}.
*/
public final class PropertyReference {
private String name;
private Method getter;
private Method setter;
private Method propertyGetter;
private Class clazz;
private Class type;
private boolean reflected = false;
// uses reflection to implement the get / set methods
/**
* Creates a new {@code PropertyReference} for a property of a bean.
*
* @param clazz
* The class of the {@link Bean} that contains the property
* @param name
* The name of the property
* @throws NullPointerException
* if {@code clazz} or {@code name} are null
* @throws IllegalArgumentException
* if {@code name} is an empty {@code String}
*/
public PropertyReference(Class clazz, String name) {
if (name == null)
throw new NullPointerException("Name must be specified");
if (name.trim().length() == 0)
throw new IllegalArgumentException("Name must be specified");
if (clazz == null)
throw new NullPointerException("Class must be specified");
ReflectUtil.checkPackageAccess(clazz);
this.name = name;
this.clazz = clazz;
}
/**
* Can be used to determine if a property can be set.
*
* @return {@code true}, if the property can be set, {@code false} otherwise
*/
public boolean isWritable() {
reflect();
return setter != null;
}
/**
* Can be used to determine if a property can be get.
*
* @return {@code true}, if the property can be get, {@code false} otherwise
*/
public boolean isReadable() {
reflect();
return getter != null;
}
/**
* Can be used to determine if a property provides an implementation of
* {@link javafx.beans.value.ObservableValue}.
*
* @return
*/
public boolean hasProperty() {
reflect();
return propertyGetter != null;
}
/**
* Returns the name of the property.
*
* @return name of the propery
*/
public String getName() {
return name;
}
/**
* Returns the class of the {@link Bean} that contains the property.
*
* @return the class of the {@link Bean}
*/
public Class getContainingClass() {
return clazz;
}
/**
* Returns the type of the property. This type is only evaluated correctly
* if a getter or a setter was found.
*
* @return the type of the property
*/
public Class getType() {
reflect();
return type;
}
/**
* Set the property to a new value.
*
* @param bean
* The {@link Bean} instance for which the property should be set
* @param value
* The new value
* @throws IllegalStateException
* if the property is not writable
*/
public void set(Object bean, T value) {
if (!isWritable())
throw new IllegalStateException(
"Cannot write to readonly property " + name);
assert setter != null;
try {
MethodHelper.invoke(setter, bean, new Object[] {value});
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
/**
* Get the value of the property.
*
* @param bean
* The {@code Bean} instance for which the property should be
* read
* @return The value of the property
* @throws IllegalStateException
* if the property is not readable
*/
@SuppressWarnings("unchecked")
public T get(Object bean) {
if (!isReadable())
throw new IllegalStateException(
"Cannot read from unreadable property " + name);
assert getter != null;
try {
return (T)MethodHelper.invoke(getter, bean, (Object[])null);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
/**
* Get the {@link javafx.beans.value.ObservableValue} implementation of the
* property.
*
* @param bean
* The {@code Bean} instance for which the property should be
* read
* @return The {@code ObservableValue} of the property
* @throws IllegalStateException
* if the property does not provide an implementation
*/
@SuppressWarnings("unchecked")
public ReadOnlyProperty getProperty(Object bean) {
if (!hasProperty())
throw new IllegalStateException("Cannot get property " + name);
assert propertyGetter != null;
try {
return (ReadOnlyProperty)MethodHelper.invoke(propertyGetter, bean, (Object[])null);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return name;
}
private void reflect() {
// If both the getter and setter are null then we have not reflected
// on this property before
if (!reflected) {
reflected = true;
try {
// Since we use it in several places, construct the
// first-letter-capitalized version of name
final String properName = name.length() == 1 ?
name.substring(0, 1).toUpperCase() :
Character.toUpperCase(name.charAt(0))
+ name.substring(1);
// Now look for the getter. It will be named either
// "get" + name with the first letter of name
// capitalized, or it will be named "is" + name with
// the first letter of the name capitalized. However it
// is only named with "is" as a prefix if the type is
// boolean.
type = null;
// first we check for getXXX
String getterName = "get" + properName;
try {
final Method m = clazz.getMethod(getterName);
if (Modifier.isPublic(m.getModifiers())) {
getter = m;
}
} catch (NoSuchMethodException ex) {
// This is a legitimate error
}
// Then if it wasn't found we look for isXXX
if (getter == null) {
getterName = "is" + properName;
try {
final Method m = clazz.getMethod(getterName);
if (Modifier.isPublic(m.getModifiers())) {
getter = m;
}
} catch (NoSuchMethodException ex) {
// This is a legitimate error
}
}
// Now attempt to look for the setter. It is simply
// "set" + name with the first letter of name
// capitalized.
final String setterName = "set" + properName;
// If we found the getter, we can get the type
// and the setter easily.
if (getter != null) {
type = getter.getReturnType();
try {
final Method m = clazz.getMethod(setterName, type);
if (Modifier.isPublic(m.getModifiers())) {
setter = m;
}
} catch (NoSuchMethodException ex) {
// This is a legitimate error
}
} else { // no getter found
final Method[] methods = clazz.getMethods();
for (final Method m : methods) {
final Class[] parameters = m.getParameterTypes();
if (setterName.equals(m.getName())
&& (parameters.length == 1)
&& Modifier.isPublic(m.getModifiers()))
{
setter = m;
type = parameters[0];
break;
}
}
}
// Now attempt to look for the property-getter.
final String propertyGetterName = name + "Property";
try {
final Method m = clazz.getMethod(propertyGetterName);
if (Modifier.isPublic(m.getModifiers())) {
propertyGetter = m;
} else
propertyGetter = null;
} catch (NoSuchMethodException ex) {
// This is a legitimate error
}
} catch (RuntimeException e) {
System.err.println("Failed to introspect property " + name);
}
}
}
/**
* {@inheritDoc}
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof PropertyReference)) {
return false;
}
final PropertyReference other = (PropertyReference) obj;
if (this.name != other.name
&& (this.name == null || !this.name.equals(other.name))) {
return false;
}
if (this.clazz != other.clazz
&& (this.clazz == null || !this.clazz.equals(other.clazz))) {
return false;
}
return true;
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
int hash = 5;
hash = 97 * hash + (this.name != null ? this.name.hashCode() : 0);
hash = 97 * hash + (this.clazz != null ? this.clazz.hashCode() : 0);
return hash;
}
}
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