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DataSourceFactory.javaAPI DocExample5211Tue Feb 28 11:34:06 GMT 2006com.ora.jsp.sql

DataSourceFactory

public class DataSourceFactory extends Object implements ObjectFactory
This class is an implementation of the ObjectFactory interface, used by a container to create instances of resources accessible through JNDI. It's intended to be used to create an instance of the DataSource class and configure it as defined by the parameters passed through the JNDI implementation.
author
Hans Bergsten, Gefion software
version
1.0

Fields Summary
Constructors Summary
Methods Summary
private java.lang.Object[]buildArgs(java.lang.String value, java.lang.reflect.Method setter)
Converts the specified String value to the setter methods parameter type, if possible, and returns it as an Object array suitable as the argument to the Method.invoke() method.

        Class[] paramTypes = setter.getParameterTypes();
        // Only one parameter for a setter method
        Object[] args = new Object[1];
        args[0] = coerceValue(value, paramTypes[0]);
        return args;
private java.lang.ObjectcoerceValue(java.lang.String value, java.lang.Class type)
Converts the specified String value to the specified type, if possible, and returns the converted value. Only conversion to Integer and Boolean is currently supported, since these types covers all DataSource implementations I've come across. It's easy to add new conversions if needed.

        Object coercedValue = null;
        if (type.isAssignableFrom(String.class)) {
            coercedValue = value;
        }
        else if (type.isAssignableFrom(Integer.class) ||
                 type.isAssignableFrom(Integer.TYPE)) {
            try {
                coercedValue = Integer.valueOf(value);
            } 
            catch (NumberFormatException e) {
                // Ignore. It's reported when trying to set the value
            }
        }
        else if (type.isAssignableFrom(Boolean.class) ||
                 type.isAssignableFrom(Boolean.TYPE)) {
            coercedValue = Boolean.valueOf(value);
        }
        return coercedValue;
public java.lang.ObjectgetObjectInstance(java.lang.Object obj, javax.naming.Name name, javax.naming.Context nameCtx, java.util.Hashtable environment)
Creates an instance of the DataSource based on the configuration info. The class name must be passed as a parameter named "dataSourceClassName". Introspection is used to find and call setter methods in the DataSource corresponding to all other parameters.


        Reference ref = (Reference) obj;
        RefAddr ra = ref.get("dataSourceClassName");
        if (ra == null) {
	    throw new NamingException("No class name specified");
        }

        String className = (String) ra.getContent();
        Object ds = null;
        try {
            ds = Class.forName(className).newInstance();
        }
        catch (Exception e) {
	    throw new NamingException("Can't create DataSource: "
                + e.getMessage());
        }

        Enumeration addrs = ref.getAll();
        while (addrs.hasMoreElements()) {
            RefAddr addr = (RefAddr) addrs.nextElement();
            String prop = addr.getType();
            String value = (String) addr.getContent();
            if (!(prop.equals("dataSourceClassName") || prop.equals("scope") ||
                prop.equals("auth") || prop.equals("factory"))) {
                setProperty(prop, value, ds);
            } 
        }
        return ds;
private java.lang.reflect.MethodgetSetter(java.lang.String prop, java.lang.Object ds)
Returns the setter method corresponding to the property name in the specified object, or null if no matching setter method is found.

        BeanInfo bi = null;
        try {
            bi = Introspector.getBeanInfo(ds.getClass());
        }
        catch (IntrospectionException e) {
            return null;
        }

        PropertyDescriptor[] pds = bi.getPropertyDescriptors();
        Method setter = null;
        for (int i = 0; i < pds.length; i++) {
            if (pds[i].getName().equals(prop)) {
                setter = pds[i].getWriteMethod();
                break;
            }
        }
        return setter;
private voidsetProperty(java.lang.String prop, java.lang.String value, java.lang.Object ds)
Sets the specified property to the specified value in the specified object.

        Method setter = getSetter(prop, ds);
        if (setter == null) {
            System.out.println("[DataSourceFactory] Can't find property: "
                + prop + ". Ignored");
            return;
        }
        Object[] args = buildArgs(value, setter);
        try {
            setter.invoke(ds, args);
        }
        catch (Exception e) {
            System.out.println("[DataSourceFactory] Can't set property: "
                + prop + "=" + value + "; " + e.getMessage() + ". Ignored");
        }