Copyright (c) 2000, 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) 2000, 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.jdt.launching;


import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.debug.core.ILaunchConfiguration;
import org.eclipse.jdt.core.IJavaProject;

Default implementation for classpath provider.

This class may be sub-classed.

Since:
2.0/**
 * Default implementation for classpath provider.
 * <p>
 * This class may be sub-classed.
 * </p>
 * @since 2.0
 */
public class StandardClasspathProvider implements IRuntimeClasspathProvider {

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.launching.IRuntimeClasspathProvider#computeUnresolvedClasspath(org.eclipse.debug.core.ILaunchConfiguration)
	 */
	@Override
	public IRuntimeClasspathEntry[] computeUnresolvedClasspath(ILaunchConfiguration configuration) throws CoreException {
		boolean useDefault = configuration.getAttribute(IJavaLaunchConfigurationConstants.ATTR_DEFAULT_CLASSPATH, true);
		boolean isModular = JavaRuntime.isModularConfiguration(configuration);
		boolean excludeTestCode = configuration.getAttribute(IJavaLaunchConfigurationConstants.ATTR_EXCLUDE_TEST_CODE, false);
		if (useDefault) {
			IJavaProject proj = JavaRuntime.getJavaProject(configuration);
			IRuntimeClasspathEntry jreEntry = JavaRuntime.computeJREEntry(configuration);
			if (proj == null) {
				//no project - use default libraries
				if (jreEntry == null) {
					return new IRuntimeClasspathEntry[0];
				}
				return new IRuntimeClasspathEntry[]{jreEntry};
			}
			IRuntimeClasspathEntry[] entries = null;
			if (isModular) {
				entries = JavaRuntime.computeUnresolvedRuntimeDependencies(proj, excludeTestCode);
			} else {
				entries = JavaRuntime.computeUnresolvedRuntimeClasspath(proj, excludeTestCode);
			}
			// replace project JRE with config's JRE
			IRuntimeClasspathEntry projEntry = isModular ? JavaRuntime.computeModularJREEntry(proj) : JavaRuntime.computeJREEntry(proj);
			if (jreEntry != null && projEntry != null) {
				if (!jreEntry.equals(projEntry)) {
					for (int i = 0; i < entries.length; i++) {
						IRuntimeClasspathEntry entry = entries[i];
						if (entry.equals(projEntry)) {
							entries[i] = jreEntry;
							return entries;
						}
					}
				}
			}
			return entries;
		}
		// recover persisted classpath
		if (isModular) {
			IRuntimeClasspathEntry[] runtimeModulePaths = recoverRuntimePath(configuration, IJavaLaunchConfigurationConstants.ATTR_MODULEPATH);
			IRuntimeClasspathEntry[] runtimeClasspaths = recoverRuntimePath(configuration, IJavaLaunchConfigurationConstants.ATTR_CLASSPATH);
			IRuntimeClasspathEntry[] result = Arrays.copyOf(runtimeModulePaths, runtimeModulePaths.length + runtimeClasspaths.length);
			System.arraycopy(runtimeClasspaths, 0, result, runtimeModulePaths.length, runtimeClasspaths.length);
			return result;
		}
		return recoverRuntimePath(configuration, IJavaLaunchConfigurationConstants.ATTR_CLASSPATH);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jdt.launching.IRuntimeClasspathProvider#resolveClasspath(org.eclipse.jdt.launching.IRuntimeClasspathEntry[], org.eclipse.debug.core.ILaunchConfiguration)
	 */
	@Override
	public IRuntimeClasspathEntry[] resolveClasspath(IRuntimeClasspathEntry[] entries, ILaunchConfiguration configuration) throws CoreException {
		// use an ordered set to avoid duplicates
		Set<IRuntimeClasspathEntry> all = new LinkedHashSet<>(entries.length);
		for (int i = 0; i < entries.length; i++) {
			IRuntimeClasspathEntry[] resolved =JavaRuntime.resolveRuntimeClasspathEntry(entries[i], configuration);
			for (int j = 0; j < resolved.length; j++) {
				all.add(resolved[j]);
			}
		}
		return all.toArray(new IRuntimeClasspathEntry[all.size()]);
	}

	
Returns a collection of runtime classpath entries that are defined in the
specified attribute of the given launch configuration. When present,
the attribute must contain a list of runtime classpath entry mementos.
Params:
configuration – launch configuration
attribute – attribute name containing the list of entries
Throws:
CoreException – if unable to retrieve the list
Returns:
collection of runtime classpath entries that are defined in the
 specified attribute of the given launch configuration/**
	 * Returns a collection of runtime classpath entries that are defined in the
	 * specified attribute of the given launch configuration. When present,
	 * the attribute must contain a list of runtime classpath entry mementos.
	 *
	 * @param configuration launch configuration
	 * @param attribute attribute name containing the list of entries
	 * @return collection of runtime classpath entries that are defined in the
	 *  specified attribute of the given launch configuration
	 * @exception CoreException if unable to retrieve the list
	 */
	protected IRuntimeClasspathEntry[] recoverRuntimePath(ILaunchConfiguration configuration, String attribute) throws CoreException {
		List<String> entries = configuration.getAttribute(attribute, Collections.EMPTY_LIST);
		IRuntimeClasspathEntry[] rtes = new IRuntimeClasspathEntry[entries.size()];
		Iterator<String> iter = entries.iterator();
		int i = 0;
		while (iter.hasNext()) {
			rtes[i] = JavaRuntime.newRuntimeClasspathEntry(iter.next());
			i++;
		}
		return rtes;
	}

}