ElementValuePair.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.compiler.lookup;

import org.eclipse.jdt.internal.compiler.ast.Annotation;
import org.eclipse.jdt.internal.compiler.ast.ArrayInitializer;
import org.eclipse.jdt.internal.compiler.ast.ClassLiteralAccess;
import org.eclipse.jdt.internal.compiler.ast.Expression;
import org.eclipse.jdt.internal.compiler.ast.FieldReference;
import org.eclipse.jdt.internal.compiler.ast.NameReference;
import org.eclipse.jdt.internal.compiler.ast.Reference;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.impl.Constant;

public class ElementValuePair {
	char[] name;

	public Object value;

	public MethodBinding binding;

	public static Object getValue(Expression expression) {
		if (expression == null)
			return null;
		Constant constant= expression.constant;
		// literals would hit this case.
		if (constant != null && constant != Constant.NotAConstant)
			return constant;

		if (expression instanceof Annotation)
			return ((Annotation)expression).getCompilerAnnotation();
		if (expression instanceof ArrayInitializer) {
			Expression[] exprs= ((ArrayInitializer)expression).expressions;
			int length= exprs == null ? 0 : exprs.length;
			Object[] values= new Object[length];
			for (int i= 0; i < length; i++)
				values[i]= getValue(exprs[i]);
			return values;
		}
		if (expression instanceof ClassLiteralAccess)
			return ((ClassLiteralAccess)expression).targetType;
		if (expression instanceof Reference) {
			FieldBinding fieldBinding= null;
			if (expression instanceof FieldReference) {
				fieldBinding= ((FieldReference)expression).fieldBinding();
			} else if (expression instanceof NameReference) {
				Binding binding= ((NameReference)expression).binding;
				if (binding != null && binding.kind() == Binding.FIELD)
					fieldBinding= (FieldBinding)binding;
			}
			if (fieldBinding != null && (fieldBinding.modifiers & ClassFileConstants.AccEnum) > 0)
				return fieldBinding;
		}
		// something that isn't a compile time constant.
		return null;
	}

	public ElementValuePair(char[] name, Expression expression, MethodBinding binding) {
		this(name, ElementValuePair.getValue(expression), binding);
	}

	public ElementValuePair(char[] name, Object value, MethodBinding binding) {
		this.name= name;
		this.value= value;
		this.binding= binding;
	}

	/**
	 * @return the name of the element value pair.
	 */
	public char[] getName() {
		return this.name;
	}

	/**
	 * @return the method binding that defined this member value pair or null if no such binding
	 *         exists.
	 */
	public MethodBinding getMethodBinding() {
		return this.binding;
	}

	/**
	 * Return {@link TypeBinding} for member value of type {@link java.lang.Class} Return
	 * {@link org.eclipse.jdt.internal.compiler.impl.Constant} for member of primitive type or
	 * String Return {@link FieldBinding} for enum constant Return {@link AnnotationBinding} for
	 * annotation instance Return <code>Object[]</code> for member value of array type.
	 * 
	 * @return the value of this member value pair or null if the value is missing or is not a
	 *         compile-time constant
	 */
	public Object getValue() {
		return this.value;
	}

	void setMethodBinding(MethodBinding binding) {
		// lazily set after annotation type was resolved
		this.binding= binding;
	}

	void setValue(Object value) {
		// can be modified after the initialization if holding an unresolved ref
		this.value= value;
	}

	public String toString() {
		StringBuffer buffer= new StringBuffer(5);
		buffer.append(this.name).append(" = "); //$NON-NLS-1$
		buffer.append(this.value);
		return buffer.toString();
	}
}