Copyright (c) 2010, 2019 Darmstadt University of Technology 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:
   Marcel Bruch - initial API and implementation.
/**
 * Copyright (c) 2010, 2019 Darmstadt University of Technology 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:
 *    Marcel Bruch - initial API and implementation.
 */
package org.eclipse.jdt.internal.ui.text;

import org.eclipse.jdt.core.IField;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.ILocalVariable;
import org.eclipse.jdt.core.IMethod;
import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.Signature;

Represents a transition from Type A to Type B by some chain element ( IField access, IMethod call, or ILocalVariable (as entrypoints only)). 
See Also:
ChainFinder/**
 * Represents a transition from Type A to Type B by some chain element ( {@link IField} access,
 * {@link IMethod} call, or {@link ILocalVariable} (as entrypoints only)).
 *
 * @see ChainFinder
 */
public class ChainElement {

	public enum ElementType {
		METHOD, FIELD, LOCAL_VARIABLE, TYPE
	}

	private final IJavaElement element;

	private ChainType returnType;

	private int dimension;

	private ElementType elementType;

	private final boolean requireThis;

	public ChainElement(final IJavaElement element, final boolean requireThis) {
		if (element == null) {
			throw new IllegalArgumentException("???"); //$NON-NLS-1$
		}
		this.element= element;
		this.requireThis= requireThis;
		initializeReturnType();
	}

	private void initializeReturnType() {
		String signature= null;
		IJavaProject proj= element.getJavaProject();
		IType declType;
		switch (element.getElementType()) {
			case IJavaElement.FIELD:
				elementType= ElementType.FIELD;
				try {
					signature= ((IField)element).getTypeSignature();
				} catch (JavaModelException e) {
					// ignore
				}
				declType= ((IField)element).getDeclaringType();
				setReturnType(proj, signature, declType);
				break;
			case IJavaElement.LOCAL_VARIABLE:
				elementType= ElementType.LOCAL_VARIABLE;
				signature= ((ILocalVariable)element).getTypeSignature();
				declType= ((ILocalVariable)element).getDeclaringMember().getDeclaringType();
				setReturnType(proj, signature, declType);
				break;
			case IJavaElement.METHOD:
				elementType= ElementType.METHOD;
				try {
					signature= ((IMethod)element).getReturnType();
				} catch (JavaModelException e) {
					// ignore
				}
				declType= ((IMethod)element).getDeclaringType();
				setReturnType(proj, signature, declType);
				break;
			case IJavaElement.TYPE:
				elementType= ElementType.TYPE;
				returnType= new ChainType((IType) element);
				break;
			default:
				/*
				 * Other IJavaElement types may end up here that
				 * are not relevant for chain completion. Ignore
				 * these using fact that getElementType() == null
				 */
		}
		dimension= signature == null ? 0 : Signature.getArrayCount(signature);
	}

	private void setReturnType(IJavaProject proj, String signature, IType declType) {
		if (ChainElementAnalyzer.isPrimitive(signature)) {
			returnType= new ChainType(signature);
		} else {
			IType res= ChainElementAnalyzer.getTypeFromSignature(proj, signature, declType);
			returnType= (res != null) ? new ChainType(res) : new ChainType(signature);
		}
	}

	public IJavaElement getElement() {
		return element;
	}

	
Returns the type of this chain element as an ElementType
Returns:
the ElementType or null, if this chain element
does not support the IJavaElement that is associated./**
	 * Returns the type of this chain element as an ElementType
	 * @return the ElementType or null, if this chain element
	 * does not support the IJavaElement that is associated.
	 */
	public ElementType getElementType() {
		return elementType;
	}

	
Returns the return type of this chain element as a ChainType
Returns:
the ChainType or null, if this chain element
does not support the IJavaElement that is associated./**
	 * Returns the return type of this chain element as a ChainType
	 * @return the ChainType or null, if this chain element
	 * does not support the IJavaElement that is associated.
	 */
	public ChainType getReturnType() {
		return returnType;
	}

	public int getReturnTypeDimension() {
		return dimension;
	}

	public boolean requiresThisForQualification() {
		return requireThis;
	}

	@Override
	public int hashCode() {
		return element.hashCode();
	}

	@Override
	public boolean equals(final Object obj) {
		if (obj instanceof ChainElement) {
			final ChainElement other= (ChainElement) obj;
			return element.equals(other.element);
		}
		return false;
	}

	@Override
	public String toString() {
		if (elementType == ElementType.METHOD) {
			final IMethod m= (IMethod) element;
			StringBuilder ret= new StringBuilder(m.getElementName());
			try {
				return ret.append(m.getSignature()).toString();
			} catch (JavaModelException e1) {
				return ret.toString();
			}
		}
		return element.toString();
	}
}