Copyright (c) 2006, 2018 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2006, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.debug.internal.core.commands;

import java.util.HashSet;
import java.util.Set;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.debug.core.IRequest;
import org.eclipse.debug.core.commands.AbstractDebugCommand;
import org.eclipse.debug.core.commands.IEnabledStateRequest;
import org.eclipse.debug.core.model.IStackFrame;
import org.eclipse.debug.core.model.IStep;
import org.eclipse.debug.core.model.IThread;

Common function for step commands.
Since:
3.3/**
 * Common function for step commands.
 *
 * @since 3.3
 */
public abstract class StepCommand extends AbstractDebugCommand {

	@Override
	protected void doExecute(Object[] targets, IProgressMonitor monitor, IRequest request) throws CoreException {
		for (Object target : targets) {
			step(target);
		}
	}

	protected abstract void step(Object target) throws CoreException ;

	@Override
	protected boolean isExecutable(Object[] targets, IProgressMonitor monitor, IEnabledStateRequest collector) throws CoreException {
		if (isThreadCompatible(targets)) {
			for (Object target : targets) {
				if (!isSteppable(target)) {
					return false;
				}
			}
			return true;
		} else {
			return false;
		}
	}

	protected abstract boolean isSteppable(Object target) throws CoreException;

	protected boolean isThreadCompatible(Object[] targets) {
		if (targets.length == 1) {
			return true;
		}
		// check if frames from same thread
		Set<IThread> threads = new HashSet<>(targets.length);
		for (Object object : targets) {
			IStackFrame frame = null;
			if (object instanceof IStackFrame) {
				frame = (IStackFrame) object;
			} else if (object instanceof IAdaptable) {
				frame = ((IAdaptable)object).getAdapter(IStackFrame.class);
			}
			if (frame != null) {
				if (!threads.add(frame.getThread())) {
					return false;
				}
			}
		}
		return true;
	}

	@Override
	protected Object getTarget(Object element) {
		return getAdapter(element, IStep.class);
	}

}