path: root/java/beans/IndexedPropertyDescriptor.java

/* java.beans.IndexedPropertyDescriptor
   Copyright (C) 1998, 2003 Free Software Foundation, Inc.

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package java.beans;

import java.lang.reflect.Array;
import java.lang.reflect.Method;

/**
 ** IndexedPropertyDescriptor describes information about a JavaBean
 ** indexed property, by which we mean an array-like property that
 ** has been exposed via a pair of get and set methods and another
 ** pair that allows you to get to the property by an index.<P>
 **
 ** An example property would have four methods like this:<P>
 ** <CODE>FooBar[] getFoo()</CODE><BR>
 ** <CODE>void setFoo(FooBar[])</CODE><BR>
 ** <CODE>FooBar getFoo(int)</CODE><BR>
 ** <CODE>void setFoo(int,FooBar)</CODE><P>
 **
 ** The constraints put on get and set methods are:<P>
 ** <OL>
 ** <LI>There must be at least a get(int) or a set(int,...) method.
 ** Nothing else is required.  <B>Spec note:</B>One nice restriction
 ** would be that if there is a get() there must be a get(int), same
 ** with set, but that is not in the spec and is fairly harmless.)</LI>
 ** <LI>A get array method must have signature
 **     <CODE>&lt;propertyType&gt;[] &lt;getMethodName&gt;()</CODE></LI>
 ** <LI>A set array method must have signature
 **     <CODE>void &lt;setMethodName&gt;(&lt;propertyType&gt;[])</CODE></LI>
 ** <LI>A get index method must have signature
 **     <CODE>&lt;propertyType&gt; &lt;getMethodName&gt;(int)</CODE></LI>
 ** <LI>A set index method must have signature
 **     <CODE>void &lt;setMethodName&gt;(int,&lt;propertyType&gt;)</CODE></LI>
 ** <LI>All these methods may throw any exception.</LI>
 ** <LI>All these methods must be public.</LI>
 ** </OL>
 **
 ** @author John Keiser
 ** @since JDK1.1
 ** @version 1.1.0, 26 Jul 1998
 **/

public class IndexedPropertyDescriptor extends PropertyDescriptor {
	private Class indexedPropertyType;
	private Method setIndex;
	private Method getIndex;

	/** Create a new IndexedPropertyDescriptor by introspection.
	 ** This form of constructor creates the PropertyDescriptor by
	 ** looking for getter methods named <CODE>get&lt;name&gt;()</CODE>
	 ** and setter methods named
	 ** <CODE>set&lt;name&gt;()</CODE> in class
	 ** <CODE>&lt;beanClass&gt;</CODE>, where &lt;name&gt; has its
	 ** first letter capitalized by the constructor.<P>
	 **
	 ** <B>Implementation note:</B> If there is a get(int) method,
	 ** then the return type of that method is used to find the
	 ** remaining methods.  If there is no get method, then the
	 ** set(int) method is searched for exhaustively and that type
	 ** is used to find the others.<P>
	 **
	 ** <B>Spec note:</B>
	 ** If there is no get(int) method and multiple set(int) methods with
	 ** the same name and the correct parameters (different type of course),
	 ** then an IntrospectionException is thrown.  While Sun's spec
	 ** does not state this, it can make Bean behavior different on
	 ** different systems (since method order is not guaranteed) and as
	 ** such, can be treated as a bug in the spec.  I am not aware of
	 ** whether Sun's implementation catches this.
	 **
	 ** @param name the programmatic name of the property, usually
	 **             starting with a lowercase letter (e.g. fooManChu
	 **             instead of FooManChu).
	 ** @param beanClass the class the get and set methods live in.
	 ** @exception IntrospectionException if the methods are not found or invalid.
	 **/
	public IndexedPropertyDescriptor(String name, Class beanClass) throws IntrospectionException {
		super(name);
		String capitalized;
		try {
			capitalized = Character.toUpperCase(name.charAt(0)) + name.substring(1);
		} catch(StringIndexOutOfBoundsException e) {
			capitalized = "";
		}
		findMethods(beanClass, "get" + capitalized, "set" + capitalized, "get" + capitalized, "set" + capitalized);
	}

	/** Create a new IndexedPropertyDescriptor by introspection.
	 ** This form of constructor allows you to specify the
	 ** names of the get and set methods to search for.<P>
	 **
	 ** <B>Implementation note:</B> If there is a get(int) method,
	 ** then the return type of that method is used to find the
	 ** remaining methods.  If there is no get method, then the
	 ** set(int) method is searched for exhaustively and that type
	 ** is used to find the others.<P>
	 **
	 ** <B>Spec note:</B>
	 ** If there is no get(int) method and multiple set(int) methods with
	 ** the same name and the correct parameters (different type of course),
	 ** then an IntrospectionException is thrown.  While Sun's spec
	 ** does not state this, it can make Bean behavior different on
	 ** different systems (since method order is not guaranteed) and as
	 ** such, can be treated as a bug in the spec.  I am not aware of
	 ** whether Sun's implementation catches this.
	 **
	 ** @param name the programmatic name of the property, usually
	 **             starting with a lowercase letter (e.g. fooManChu
	 **             instead of FooManChu).
	 ** @param beanClass the class the get and set methods live in.
	 ** @param getMethodName the name of the get array method.
	 ** @param setMethodName the name of the set array method.
	 ** @param getIndexName the name of the get index method.
	 ** @param setIndexName the name of the set index method.
	 ** @exception IntrospectionException if the methods are not found or invalid.
	 **/
	public IndexedPropertyDescriptor(String name, Class beanClass, String getMethodName, String setMethodName, String getIndexName, String setIndexName) throws IntrospectionException {
		super(name);
		findMethods(beanClass, getMethodName, setMethodName, getIndexName, setIndexName);
	}

	/** Create a new PropertyDescriptor using explicit Methods.
	 ** Note that the methods will be checked for conformance to standard
	 ** Property method rules, as described above at the top of this class.
	 ** 
	 ** @param name the programmatic name of the property, usually
	 **             starting with a lowercase letter (e.g. fooManChu
	 **             instead of FooManChu).
	 ** @param getMethod the get array method.
	 ** @param setMethod the set array method.
	 ** @param getIndex the get index method.
	 ** @param setIndex the set index method.
	 ** @exception IntrospectionException if the methods are not found or invalid.
	 **/
	public IndexedPropertyDescriptor(String name, Method getMethod, Method setMethod, Method getIndex, Method setIndex) throws IntrospectionException {
		super(name);
		if(getMethod != null && getMethod.getParameterTypes().length > 0) {
			throw new IntrospectionException("get method has parameters");
		}
		if(getMethod != null && setMethod.getParameterTypes().length != 1) {
			throw new IntrospectionException("set method does not have exactly one parameter");
		}
		if(getMethod != null && setMethod != null) {
			if(!getMethod.getReturnType().equals(setMethod.getParameterTypes()[0])) {
				throw new IntrospectionException("set and get methods do not share the same type");
			}
			if(!getMethod.getDeclaringClass().isAssignableFrom(setMethod.getDeclaringClass())
			   && !setMethod.getDeclaringClass().isAssignableFrom(getMethod.getDeclaringClass())) {
				throw new IntrospectionException("set and get methods are not in the same class.");
			}
		}

		if(getIndex != null && (getIndex.getParameterTypes().length != 1
		   || !(getIndex.getParameterTypes()[0]).equals(java.lang.Integer.TYPE))) {
			throw new IntrospectionException("get index method has wrong parameters");
		}
		if(setIndex != null && (setIndex.getParameterTypes().length != 2
		   || !(setIndex.getParameterTypes()[0]).equals(java.lang.Integer.TYPE))) {
			throw new IntrospectionException("set index method has wrong parameters");
		}
		if(getIndex != null && setIndex != null) {
			if(!getIndex.getReturnType().equals(setIndex.getParameterTypes()[1])) {
				throw new IntrospectionException("set index methods do not share the same type");
			}
			if(!getIndex.getDeclaringClass().isAssignableFrom(setIndex.getDeclaringClass())
			   && !setIndex.getDeclaringClass().isAssignableFrom(getIndex.getDeclaringClass())) {
				throw new IntrospectionException("get and set index methods are not in the same class.");
			}
		}

		if(getIndex != null && getMethod != null && !getIndex.getDeclaringClass().isAssignableFrom(getMethod.getDeclaringClass())
		   && !getMethod.getDeclaringClass().isAssignableFrom(getIndex.getDeclaringClass())) {
			throw new IntrospectionException("methods are not in the same class.");
		}

		if(getIndex != null && getMethod != null && !Array.newInstance(getIndex.getReturnType(),0).getClass().equals(getMethod.getReturnType())) {
			throw new IntrospectionException("array methods do not match index methods.");
		}

		this.getMethod = getMethod;
		this.setMethod = setMethod;
		this.getIndex = getIndex;
		this.setIndex = setIndex;
		this.indexedPropertyType = getIndex != null ? getIndex.getReturnType() : setIndex.getParameterTypes()[1];
		this.propertyType = getMethod != null ? getMethod.getReturnType() : (setMethod != null ? setMethod.getParameterTypes()[0] : Array.newInstance(this.indexedPropertyType,0).getClass());
	}

	public Class getIndexedPropertyType() {
		return indexedPropertyType;
	}

	public Method getIndexedReadMethod() {
		return getIndex;
	}

	public Method getIndexedWriteMethod() {
		return setIndex;
	}

	private void findMethods(Class beanClass, String getMethodName, String setMethodName, String getIndexName, String setIndexName) throws IntrospectionException {
		try {
			if(getIndexName != null) {
				try {
					Class[] getArgs = new Class[1];
					getArgs[0] = java.lang.Integer.TYPE;
					getIndex = beanClass.getMethod(getIndexName,getArgs);
					indexedPropertyType = getIndex.getReturnType();
				} catch(NoSuchMethodException E) {
				}
			}
			if(getIndex != null) {
				if(setIndexName != null) {
					try {
						Class[] setArgs = new Class[2];
						setArgs[0] = java.lang.Integer.TYPE;
						setArgs[1] = indexedPropertyType;
						setIndex = beanClass.getMethod(setIndexName,setArgs);
						if(!setIndex.getReturnType().equals(java.lang.Void.TYPE)) {
							throw new IntrospectionException(setIndexName + " has non-void return type");
						}
					} catch(NoSuchMethodException E) {
					}
				}
			} else if(setIndexName != null) {
				Method[] m = beanClass.getMethods();
				for(int i=0;i<m.length;i++) {
					Method current = m[i];
					if(current.getName().equals(setIndexName)
					   && current.getParameterTypes().length == 2
					   && (current.getParameterTypes()[0]).equals(java.lang.Integer.TYPE)
					   && current.getReturnType().equals(java.lang.Void.TYPE)) {
						if(setIndex != null) {
							throw new IntrospectionException("Multiple, different set methods found that fit the bill!");
						} else {
							setIndex = current;
							indexedPropertyType = current.getParameterTypes()[1];
						}
					}
				}
				if(setIndex == null) {
					throw new IntrospectionException("Cannot find get or set methods.");
				}
			} else {
				throw new IntrospectionException("Cannot find get or set methods.");
			}

			Class arrayType = Array.newInstance(indexedPropertyType,0).getClass();

			Class[] setArgs = new Class[1];
			setArgs[0] = arrayType;
			try {
				setMethod = beanClass.getMethod(setMethodName,setArgs);
				if(!setMethod.getReturnType().equals(java.lang.Void.TYPE)) {
					setMethod = null;
				}
			} catch(NoSuchMethodException E) {
			}

			Class[] getArgs = new Class[0];
			try {
				getMethod = beanClass.getMethod(getMethodName,getArgs);
				if(!getMethod.getReturnType().equals(arrayType)) {
					getMethod = null;
				}
			} catch(NoSuchMethodException E) {
			}
		} catch(SecurityException E) {
			throw new IntrospectionException("SecurityException while trying to find methods.");
		}
	}
}