javax.faces.component.MethodExpressionMethodBindingAdapter Maven / Gradle / Ivy
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package javax.faces.component;
import javax.el.MethodExpression;
import javax.el.ELException;
import javax.el.ELContext;
import javax.el.MethodInfo;
import javax.faces.el.MethodBinding;
import javax.faces.context.FacesContext;
import javax.faces.component.StateHolder;
import javax.el.ExpressionFactory;
import javax.el.ValueExpression;
import java.util.Arrays;
import java.lang.reflect.Method;
import java.io.Serializable;
/**
* Wrap a MethodBinding instance and expose it as a
* MethodExpression.
*/
class MethodExpressionMethodBindingAdapter extends MethodExpression implements Serializable, StateHolder {
private static final long serialVersionUID = -1822420567946048452L;
public MethodExpressionMethodBindingAdapter() {} // for StateHolder
private MethodBinding binding = null;
MethodExpressionMethodBindingAdapter(MethodBinding binding) {
assert(null != binding);
this.binding = binding;
}
//
// Methods from MethodExpression
//
private transient MethodInfo info = null;
public MethodInfo getMethodInfo(ELContext context) throws ELException {
assert(null != binding);
if (context == null) {
throw new NullPointerException("ELContext -> null");
}
if (null == info) {
FacesContext facesContext = (FacesContext)
context.getContext(FacesContext.class);
if (null != facesContext) {
try {
//PENDING - we should find a way to provide more information
info = new MethodInfo(null, binding.getType(facesContext), null);
}
catch (Exception e) {
throw new ELException(e);
}
}
}
return info;
}
public Object invoke(ELContext context, Object[] params) throws ELException {
assert(null != binding);
if (context == null) {
throw new NullPointerException("ELContext -> null");
}
Object result = null;
FacesContext facesContext = (FacesContext)
context.getContext(FacesContext.class);
if (null != facesContext) {
try {
result = binding.invoke(facesContext, params);
}
catch (Exception e) {
throw new ELException(e);
}
}
return result;
}
public String getExpressionString() {
assert(null != binding);
return binding.getExpressionString();
}
public boolean isLiteralText() {
assert (binding != null);
String expr = binding.getExpressionString();
return (!(expr.startsWith("#{")
&& expr.endsWith("}")));
}
public boolean equals(Object other) {
if (other == this) {
return true;
}
if (other instanceof MethodExpressionMethodBindingAdapter) {
MethodBinding ob = ((MethodExpressionMethodBindingAdapter) other).getWrapped();
return (binding.equals(ob));
} else if (other instanceof MethodExpression) {
MethodExpression expression = (MethodExpression) other;
// We'll need to do a little leg work to determine
// if the MethodBinding is equivalent to the
// wrapped MethodExpression
String expr = binding.getExpressionString();
int idx = expr.indexOf('.');
String target = expr.substring(0, idx).substring(2);
String t = expr.substring(idx + 1);
String method = t.substring(0, (t.length() - 1));
FacesContext context = FacesContext.getCurrentInstance();
ELContext elContext = context.getELContext();
MethodInfo controlInfo = expression.getMethodInfo(elContext);
// ensure the method names are the same
if (!controlInfo.getName().equals(method)) {
return false;
}
// Using the target, create an expression and evaluate
// it.
ExpressionFactory factory = context.getApplication().getExpressionFactory();
ValueExpression ve = factory.createValueExpression(elContext,
"#{" + target + '}',
Object.class);
if (ve == null) {
return false;
}
Object result = ve.getValue(elContext);
if (result == null) {
return false;
}
// Get all of the methods with the matching name and try
// to find a match based on controlInfo's return and parameter
// types
Method[] methods = result.getClass().getMethods();
for (Method meth : methods) {
if (meth.getName().equals(method)
&& meth.getReturnType().equals(controlInfo.getReturnType())
&& Arrays.equals(meth.getParameterTypes(),
controlInfo.getParamTypes())) {
return true;
}
}
}
return false;
}
public int hashCode() {
assert(null != binding);
return binding.hashCode();
}
public String getDelimiterSyntax() {
// PENDING (visvan) Implementation
return "";
}
//
// Methods from StateHolder
//
public Object saveState(FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
Object result = null;
if (!tranzient) {
if (binding instanceof StateHolder) {
Object [] stateStruct = new Object[2];
// save the actual state of our wrapped binding
stateStruct[0] = ((StateHolder)binding).saveState(context);
// save the class name of the binding impl
stateStruct[1] = binding.getClass().getName();
result = stateStruct;
}
else {
result = binding;
}
}
return result;
}
public void restoreState(FacesContext context, Object state) {
if (context == null) {
throw new NullPointerException();
}
// if we have state
if (null == state) {
return;
}
if (!(state instanceof MethodBinding)) {
Object [] stateStruct = (Object []) state;
Object savedState = stateStruct[0];
String className = stateStruct[1].toString();
MethodBinding result = null;
Class toRestoreClass = null;
if (null != className) {
try {
toRestoreClass = loadClass(className, this);
}
catch (ClassNotFoundException e) {
throw new IllegalStateException(e.getMessage());
}
if (null != toRestoreClass) {
try {
result =
(MethodBinding) toRestoreClass.newInstance();
}
catch (InstantiationException e) {
throw new IllegalStateException(e.getMessage());
}
catch (IllegalAccessException a) {
throw new IllegalStateException(a.getMessage());
}
}
if (null != result && null != savedState) {
// don't need to check transient, since that was
// done on the saving side.
((StateHolder)result).restoreState(context, savedState);
}
binding = result;
}
}
else {
binding = (MethodBinding) state;
}
}
private boolean tranzient = false;
public boolean isTransient() {
return tranzient;
}
public void setTransient(boolean newTransientMethod) {
tranzient = newTransientMethod;
}
//
// Helper methods for StateHolder
//
private static Class loadClass(String name,
Object fallbackClass) throws ClassNotFoundException {
ClassLoader loader =
Thread.currentThread().getContextClassLoader();
if (loader == null) {
loader = fallbackClass.getClass().getClassLoader();
}
return Class.forName(name, true, loader);
}
//
// methods used by classes aware of this class's wrapper nature
//
public MethodBinding getWrapped() {
return binding;
}
}