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/*
 * Copyright 2006-2009 Odysseus Software GmbH
 *
 * Licensed 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 de.odysseus.el.tree.impl.ast;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Arrays;

import javax.el.ELContext;
import javax.el.ELException;
import javax.el.MethodExpression;
import javax.el.MethodInfo;
import javax.el.MethodNotFoundException;
import javax.el.PropertyNotFoundException;
import javax.el.ValueExpression;
import javax.el.ValueReference;

import de.odysseus.el.misc.LocalMessages;
import de.odysseus.el.tree.Bindings;
import de.odysseus.el.tree.IdentifierNode;

public class AstIdentifier extends AstNode implements IdentifierNode {
	private final String name;
	private final int index;
	private final boolean ignoreReturnType;

	public AstIdentifier(String name, int index) {
		this(name, index, false);
	}

	public AstIdentifier(String name, int index, boolean ignoreReturnType) {
		this.name = name;
		this.index = index;
		this.ignoreReturnType = ignoreReturnType;
	}

	public Class getType(Bindings bindings, ELContext context) {
		ValueExpression expression = bindings.getVariable(index);
		if (expression != null) {
			return expression.getType(context);
		}
		context.setPropertyResolved(false);
		Class result = context.getELResolver().getType(context, null, name);
		if (!context.isPropertyResolved()) {
			throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
		}
		return result;
	}


	public boolean isLeftValue() {
		return true;
	}

	public boolean isMethodInvocation() {
		return false;
	}
	
	public boolean isLiteralText() {
		return false;
	}

	public ValueReference getValueReference(Bindings bindings, ELContext context) {
		ValueExpression expression = bindings.getVariable(index);
		if (expression != null) {
			return expression.getValueReference(context);
		}
		return new ValueReference(null, name);
	}
	
	@Override 
	public Object eval(Bindings bindings, ELContext context) {
		ValueExpression expression = bindings.getVariable(index);
		if (expression != null) {
			return expression.getValue(context);
		}
		context.setPropertyResolved(false);
		Object result = context.getELResolver().getValue(context, null, name);
		if (!context.isPropertyResolved()) {
			throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
		}
		return result;
	}

	public void setValue(Bindings bindings, ELContext context, Object value) {
		ValueExpression expression = bindings.getVariable(index);
		if (expression != null) {
			expression.setValue(context, value);
			return;
		}
		context.setPropertyResolved(false);
		Class type = context.getELResolver().getType(context, null, name);
		if (context.isPropertyResolved()) {
			if (type != null && (value != null || type.isPrimitive())) {
				value = bindings.convert(value, type);
			}
			context.setPropertyResolved(false);
		}
		context.getELResolver().setValue(context, null, name, value);
		if (!context.isPropertyResolved()) {
			throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
		}
	}

	public boolean isReadOnly(Bindings bindings, ELContext context) {
		ValueExpression expression = bindings.getVariable(index);
		if (expression != null) {
			return expression.isReadOnly(context);
		}
		context.setPropertyResolved(false);
		boolean result = context.getELResolver().isReadOnly(context, null, name);
		if (!context.isPropertyResolved()) {
			throw new PropertyNotFoundException(LocalMessages.get("error.identifier.property.notfound", name));
		}
		return result;
	}

	protected MethodExpression getMethodExpression(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes) {
		Object value = eval(bindings, context);
		if (value == null) {
			throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
		}
		if (value instanceof Method) {
			final Method method = findAccessibleMethod((Method)value);
			if (method == null) {
				throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
			}
			if (!ignoreReturnType && returnType != null && !returnType.isAssignableFrom(method.getReturnType())) {
				throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.returntype", method.getReturnType(), name, returnType));
			}
			if (!Arrays.equals(method.getParameterTypes(), paramTypes)) {
				throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notfound", name));
			}
			return new MethodExpression() {
				private static final long serialVersionUID = 1L;
				@Override
				public boolean isLiteralText() {
					return false;
				}
				@Override
				public String getExpressionString() {
					return null;
				}
				@Override
				public int hashCode() {
					return 0;
				}
				@Override
				public boolean equals(Object obj) {
					return obj == this;
				}
				@Override
				public Object invoke(ELContext context, Object[] params) {
					try {
						return method.invoke(null, params);
					} catch (IllegalAccessException e) {
						throw new ELException(LocalMessages.get("error.identifier.method.access", name));
					} catch (IllegalArgumentException e) {
						throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e));
					} catch (InvocationTargetException e) {
						throw new ELException(LocalMessages.get("error.identifier.method.invocation", name, e.getCause()));
					}
				}			
				@Override
				public MethodInfo getMethodInfo(ELContext context) {
					return new MethodInfo(method.getName(), method.getReturnType(), method.getParameterTypes());
				}
			};
		} else if (value instanceof MethodExpression) {
			return (MethodExpression)value;
		}
		throw new MethodNotFoundException(LocalMessages.get("error.identifier.method.notamethod", name, value.getClass()));
	}

	public MethodInfo getMethodInfo(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes) {
		return getMethodExpression(bindings, context, returnType, paramTypes).getMethodInfo(context);
	}

	public Object invoke(Bindings bindings, ELContext context, Class returnType, Class[] paramTypes, Object[] params) {
		return getMethodExpression(bindings, context, returnType, paramTypes).invoke(context, params);
	}

	@Override
	public String toString() {
		return name;
	}

	@Override 
	public void appendStructure(StringBuilder b, Bindings bindings) {
		b.append(bindings != null && bindings.isVariableBound(index) ? "" : name);
	}

	public int getIndex() {
		return index;
	}

	public String getName() {
		return name;
	}

	public int getCardinality() {
		return 0;
	}

	public AstNode getChild(int i) {
		return null;
	}
}