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org.apache.commons.jexl2.introspection.UberspectImpl Maven / Gradle / Ivy
Jexl is an implementation of the JSTL Expression Language with extensions.
/*
* 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 java.beans.IntrospectionException;
import org.apache.commons.jexl2.internal.Introspector;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;
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.
* This is the class to derive to customize introspection.
*
* @since 1.0
*/
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);
}
/**
* Resets this Uberspect class loader.
* @param cloader the class loader to use
* @since 2.1
*/
public void setLoader(ClassLoader cloader) {
base().setLoader(cloader);
}
/**
* {@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((Enumeration) 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) it.execute(obj, null);
}
} catch (Exception xany) {
throw new JexlException(info, "unable to generate iterator()", xany);
}
return null;
}
/**
* {@inheritDoc}
*/
public JexlMethod getMethod(Object obj, String method, Object[] args, JexlInfo info) {
return getMethodExecutor(obj, method, args);
}
/**
* {@inheritDoc}
*/
@Deprecated
public Constructor getConstructor(Object ctorHandle, Object[] args, JexlInfo info) {
return getConstructor(ctorHandle, args);
}
/**
* {@inheritDoc}
* @since 2.1
*/
public JexlMethod getConstructorMethod(Object ctorHandle, Object[] args, JexlInfo info) {
final Constructor ctor = getConstructor(ctorHandle, args);
if (ctor != null) {
return new ConstructorMethod(ctor);
} else {
return null;
}
}
/**
* {@inheritDoc}
*/
public JexlPropertyGet getPropertyGet(Object obj, Object identifier, JexlInfo info) {
JexlPropertyGet get = getGetExecutor(obj, identifier);
if (get == null && obj != null && identifier != null) {
get = getIndexedGet(obj, identifier.toString());
if (get == null) {
Field field = getField(obj, identifier.toString(), info);
if (field != null) {
return new FieldPropertyGet(field);
}
}
}
return get;
}
/**
* {@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;
}
/**
* Returns a class field.
* Only for use by sub-classes, will be made protected in a later version
* @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);
}
/**
* Attempts to find an indexed-property getter in an object.
* The code attempts to find the list of methods getXXX() and setXXX().
* Note that this is not equivalent to the strict bean definition of indexed properties; the type of the key
* is not necessarily an int and the set/get arrays are not resolved.
* @param object the object
* @param name the container name
* @return a JexlPropertyGet is successfull, null otherwise
* @since 2.1
*/
protected JexlPropertyGet getIndexedGet(Object object, String name) {
if (object != null && name != null) {
String base = name.substring(0, 1).toUpperCase() + name.substring(1);
final String container = name;
final Class clazz = object.getClass();
final Method[] getters = getMethods(object.getClass(), "get" + base);
final Method[] setters = getMethods(object.getClass(), "set" + base);
if (getters != null) {
return new IndexedType(container, clazz, getters, setters);
}
}
return null;
}
/**
* Abstract an indexed property container.
* This stores the container name and owning class as well as the list of available getter and setter methods.
* It implements JexlPropertyGet since such a container can only be accessed from its owning instance (not set).
* @since 2.1
*/
private static final class IndexedType implements JexlPropertyGet {
/** The container name. */
private final String container;
/** The owning class. */
private final Class clazz;
/** The array of getter methods. */
private final Method[] getters;
/** The array of setter methods. */
private final Method[] setters;
/**
* Creates a new indexed type.
* @param name the container name
* @param c the owning class
* @param gets the array of getter methods
* @param sets the array of setter methods
*/
IndexedType(String name, Class c, Method[] gets, Method[] sets) {
this.container = name;
this.clazz = c;
this.getters = gets;
this.setters = sets;
}
/**
* {@inheritDoc}
*/
public Object invoke(Object obj) throws Exception {
if (obj != null && clazz.equals(obj.getClass())) {
return new IndexedContainer(this, obj);
} else {
throw new IntrospectionException("property resolution error");
}
}
/**
* {@inheritDoc}
*/
public Object tryInvoke(Object obj, Object key) {
if (obj != null && key != null && clazz.equals(obj.getClass()) && container.equals(key.toString())) {
return new IndexedContainer(this, obj);
} else {
return TRY_FAILED;
}
}
/**
* {@inheritDoc}
*/
public boolean tryFailed(Object rval) {
return rval == TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean isCacheable() {
return true;
}
/**
* Gets the value of a property from a container.
* @param object the instance owning the container (not null)
* @param key the property key (not null)
* @return the property value
* @throws Exception if invocation failed; IntrospectionException if a property getter could not be found
*/
private Object invokeGet(Object object, Object key) throws Exception {
if (getters != null) {
final Object[] args = {key};
final Method jm;
if (getters.length == 1) {
jm = getters[0];
} else {
jm = new MethodKey(getters[0].getName(), args).getMostSpecificMethod(Arrays.asList(getters));
}
if (jm != null) {
return jm.invoke(object, args);
}
}
throw new IntrospectionException("property get error: "
+ object.getClass().toString() + "@" + key.toString());
}
/**
* Sets the value of a property in a container.
* @param object the instance owning the container (not null)
* @param key the property key (not null)
* @param value the property value (not null)
* @return the result of the method invocation (frequently null)
* @throws Exception if invocation failed; IntrospectionException if a property setter could not be found
*/
private Object invokeSet(Object object, Object key, Object value) throws Exception {
if (setters != null) {
final Object[] args = {key, value};
final Method jm;
if (setters.length == 1) {
jm = setters[0];
} else {
jm = new MethodKey(setters[0].getName(), args).getMostSpecificMethod(Arrays.asList(setters));
}
if (jm != null) {
return jm.invoke(object, args);
}
}
throw new IntrospectionException("property set error: "
+ object.getClass().toString() + "@" + key.toString());
}
}
/**
* A generic indexed property container, exposes get(key) and set(key, value) and solves method call dynamically
* based on arguments.
* @since 2.1
*/
public static final class IndexedContainer {
/** The instance owning the container. */
private final Object object;
/** The container type instance. */
private final IndexedType type;
/**
* Creates a new duck container.
* @param theType the container type
* @param theObject the instance owning the container
*/
private IndexedContainer(IndexedType theType, Object theObject) {
this.type = theType;
this.object = theObject;
}
/**
* Gets a property from a container.
* @param key the property key
* @return the property value
* @throws Exception if inner invocation fails
*/
public Object get(Object key) throws Exception {
return type.invokeGet(object, key);
}
/**
* Sets a property in a container.
* @param key the property key
* @param value the property value
* @return the invocation result (frequently null)
* @throws Exception if inner invocation fails
*/
public Object set(Object key, Object value) throws Exception {
return type.invokeSet(object, key, value);
}
}
/**
* A JexlMethod that wraps constructor.
* @since 2.1
*/
private final class ConstructorMethod implements JexlMethod {
/** The wrapped constructor. */
private final Constructor ctor;
/**
* Creates a constructor method.
* @param theCtor the constructor to wrap
*/
private ConstructorMethod(Constructor theCtor) {
this.ctor = theCtor;
}
/**
* {@inheritDoc}
*/
public Object invoke(Object obj, Object[] params) throws Exception {
Class clazz = null;
if (obj instanceof Class) {
clazz = (Class) obj;
} else if (obj != null) {
clazz = getClassByName(obj.toString());
} else {
clazz = ctor.getDeclaringClass();
}
if (clazz.equals(ctor.getDeclaringClass())) {
return ctor.newInstance(params);
} else {
throw new IntrospectionException("constructor resolution error");
}
}
/**
* {@inheritDoc}
*/
public Object tryInvoke(String name, Object obj, Object[] params) {
Class clazz = null;
if (obj instanceof Class) {
clazz = (Class) obj;
} else if (obj != null) {
clazz = getClassByName(obj.toString());
} else {
clazz = ctor.getDeclaringClass();
}
if (clazz.equals(ctor.getDeclaringClass())
&& (name == null || name.equals(clazz.getName()))) {
try {
return ctor.newInstance(params);
} catch (InstantiationException xinstance) {
return TRY_FAILED;
} catch (IllegalAccessException xaccess) {
return TRY_FAILED;
} catch (IllegalArgumentException xargument) {
return TRY_FAILED;
} catch (InvocationTargetException xinvoke) {
return TRY_FAILED;
}
}
return TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean tryFailed(Object rval) {
return rval == TRY_FAILED;
}
/**
* {@inheritDoc}
*/
public boolean isCacheable() {
return true;
}
/**
* {@inheritDoc}
*/
public Class getReturnType() {
return ctor.getDeclaringClass();
}
}
/**
* A JexlPropertyGet for public fields.
* @deprecated Do not use externally - will be made private in a later version
*/
@Deprecated
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;
}
}
/**
* A JexlPropertySet for public fields.
* @deprecated Do not use externally - will be made private in a later version
*/
@Deprecated
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;
}
}
}
