/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.jexl2.introspection;
import org.apache.commons.jexl2.internal.Introspector;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.jexl2.JexlInfo;
import org.apache.commons.jexl2.JexlException;
import org.apache.commons.jexl2.internal.AbstractExecutor;
import org.apache.commons.jexl2.internal.ArrayIterator;
import org.apache.commons.jexl2.internal.EnumerationIterator;
import org.apache.commons.jexl2.internal.introspection.MethodKey;
import org.apache.commons.logging.Log;
/**
* Implementation of Uberspect to provide the default introspective
* functionality of JEXL.
* <p>This is the class to derive to customize introspection.</p>
*
* @since 1.0
* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
* @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
* @version $Id: UberspectImpl.java 896952 2010-01-07 18:21:29Z henrib $
*/
public class UberspectImpl extends Introspector implements Uberspect {
/**
* Publicly exposed special failure object returned by tryInvoke.
*/
public static final Object TRY_FAILED = AbstractExecutor.TRY_FAILED;
/**
* Creates a new UberspectImpl.
* @param runtimeLogger the logger used for all logging needs
*/
public UberspectImpl(Log runtimeLogger) {
super(runtimeLogger);
}
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
public Iterator<?> getIterator(Object obj, JexlInfo info) {
if (obj instanceof Iterator<?>) {
return ((Iterator<?>) obj);
}
if (obj.getClass().isArray()) {
return new ArrayIterator(obj);
}
if (obj instanceof Map<?,?>) {
return ((Map<?,?>) obj).values().iterator();
}
if (obj instanceof Enumeration<?>) {
return new EnumerationIterator<Object>((Enumeration<Object>) obj);
}
if (obj instanceof Iterable<?>) {
return ((Iterable<?>) obj).iterator();
}
try {
// look for an iterator() method to support the JDK5 Iterable
// interface or any user tools/DTOs that want to work in
// foreach without implementing the Collection interface
AbstractExecutor.Method it = getMethodExecutor(obj, "iterator", null);
if (it != null && Iterator.class.isAssignableFrom(it.getReturnType())) {
return (Iterator<Object>) it.execute(obj, null);
}
} catch(Exception xany) {
throw new JexlException(info, "unable to generate iterator()", xany);
}
return null;
}
/**
* Returns a class field.
* @param obj the object
* @param name the field name
* @param info debug info
* @return a {@link Field}.
*/
public Field getField(Object obj, String name, JexlInfo info) {
final Class<?> clazz = obj instanceof Class<?>? (Class<?>) obj : obj.getClass();
return getField(clazz, name);
}
/**
* {@inheritDoc}
*/
public Constructor<?> getConstructor(Object ctorHandle, Object[] args, JexlInfo info) {
return getConstructor(ctorHandle, args);
}
/**
* {@inheritDoc}
*/
public JexlMethod getMethod(Object obj, String method, Object[] args, JexlInfo info) {
return getMethodExecutor(obj, method, args);
}
/**
* A JexlPropertyGet for public fields.
*/
public static final class FieldPropertyGet implements JexlPropertyGet {
/**
* The public field.
*/
private final Field field;
/**
* Creates a new instance of FieldPropertyGet.
* @param theField the class public field
*/
public FieldPropertyGet(Field theField) {
field = theField;
}
/**
* {@inheritDoc}
*/
public Object invoke(Object obj) throws Exception {
return field.get(obj);
}
/**
* {@inheritDoc}
*/
public Object tryInvoke(Object obj, Object key) {
if (obj.getClass().equals(field.getDeclaringClass()) && key.equals(field.getName())) {
try {
return field.get(obj);
} catch (IllegalAccessException xill) {
return TRY_FAILED;
}
}
return TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean tryFailed(Object rval) {
return rval == TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean isCacheable() {
return true;
}
}
/**
* {@inheritDoc}
*/
public JexlPropertyGet getPropertyGet(Object obj, Object identifier, JexlInfo info) {
JexlPropertyGet get = getGetExecutor(obj, identifier);
if (get == null && obj != null && identifier != null) {
Field field = getField(obj, identifier.toString(), info);
if (field != null) {
return new FieldPropertyGet(field);
}
}
return get;
}
/**
* A JexlPropertySet for public fields.
*/
public static final class FieldPropertySet implements JexlPropertySet {
/**
* The public field.
*/
private final Field field;
/**
* Creates a new instance of FieldPropertySet.
* @param theField the class public field
*/
public FieldPropertySet(Field theField) {
field = theField;
}
/**
* {@inheritDoc}
*/
public Object invoke(Object obj, Object arg) throws Exception {
field.set(obj, arg);
return arg;
}
/**
* {@inheritDoc}
*/
public Object tryInvoke(Object obj, Object key, Object value) {
if (obj.getClass().equals(field.getDeclaringClass())
&& key.equals(field.getName())
&& (value == null || MethodKey.isInvocationConvertible(field.getType(), value.getClass(), false))) {
try {
field.set(obj, value);
return value;
} catch (IllegalAccessException xill) {
return TRY_FAILED;
}
}
return TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean tryFailed(Object rval) {
return rval == TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean isCacheable() {
return true;
}
}
/**
* {@inheritDoc}
*/
public JexlPropertySet getPropertySet(final Object obj, final Object identifier, Object arg, JexlInfo info) {
JexlPropertySet set = getSetExecutor(obj, identifier, arg);
if (set == null && obj != null && identifier != null) {
Field field = getField(obj, identifier.toString(), info);
if (field != null
&& !Modifier.isFinal(field.getModifiers())
&& (arg == null || MethodKey.isInvocationConvertible(field.getType(), arg.getClass(), false))) {
return new FieldPropertySet(field);
}
}
return set;
}
}