http://www.eclipse.org/jdt: Java Development Tools Launching Support (Eclipse Foundation) 
Copyright (c) 2006, 2019 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, 2019 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.internal.launching.environments;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jdt.internal.launching.EEVMInstall;
import org.eclipse.jdt.internal.launching.EEVMType;
import org.eclipse.jdt.launching.IVMInstall;
import org.eclipse.jdt.launching.IVMInstall2;
import org.eclipse.jdt.launching.IVMInstall3;
import org.eclipse.jdt.launching.JavaRuntime;
import org.eclipse.jdt.launching.environments.CompatibleEnvironment;
import org.eclipse.jdt.launching.environments.IExecutionEnvironment;
import org.eclipse.jdt.launching.environments.IExecutionEnvironmentAnalyzerDelegate;
import org.eclipse.jdt.launching.environments.IExecutionEnvironmentsManager;

Environment analyzer for standard execution environments.

Since:3.3
/**
 * Environment analyzer for standard execution environments.
 *
 * @since 3.3
 */
public class ExecutionEnvironmentAnalyzer implements IExecutionEnvironmentAnalyzerDelegate {

	// XXX: Note that this string is not yet standardized by OSGi, see http://wiki.osgi.org/wiki/Execution_Environment

	private static final String JavaSE_13 = "JavaSE-13"; //$NON-NLS-1$
	private static final String JavaSE_12 = "JavaSE-12"; //$NON-NLS-1$
	private static final String JavaSE_11 = "JavaSE-11"; //$NON-NLS-1$
	private static final String JavaSE_10_Plus = "JavaSE-10+"; //$NON-NLS-1$
	private static final String JavaSE_10 = "JavaSE-10"; //$NON-NLS-1$
	static final String JavaSE_9 = "JavaSE-9"; //$NON-NLS-1$
	private static final String JavaSE_1_8 = "JavaSE-1.8"; //$NON-NLS-1$

	private static final String JavaSE_1_7 = "JavaSE-1.7"; //$NON-NLS-1$
	private static final String JavaSE_1_6 = "JavaSE-1.6"; //$NON-NLS-1$
	private static final String J2SE_1_5 = "J2SE-1.5"; //$NON-NLS-1$
	private static final String J2SE_1_4 = "J2SE-1.4"; //$NON-NLS-1$
	private static final String J2SE_1_3 = "J2SE-1.3"; //$NON-NLS-1$
	private static final String J2SE_1_2 = "J2SE-1.2"; //$NON-NLS-1$
	private static final String JRE_1_1 = "JRE-1.1"; //$NON-NLS-1$

	private static final String CDC_FOUNDATION_1_1 = "CDC-1.1/Foundation-1.1"; //$NON-NLS-1$
	private static final String CDC_FOUNDATION_1_0 = "CDC-1.0/Foundation-1.0"; //$NON-NLS-1$

	private static final String OSGI_MINIMUM_1_0 = "OSGi/Minimum-1.0"; //$NON-NLS-1$
	private static final String OSGI_MINIMUM_1_1 = "OSGi/Minimum-1.1"; //$NON-NLS-1$
	private static final String OSGI_MINIMUM_1_2 = "OSGi/Minimum-1.2"; //$NON-NLS-1$

	private static final String JAVA_SPEC_VERSION = "java.specification.version"; //$NON-NLS-1$
	private static final String JAVA_SPEC_NAME = "java.specification.name"; //$NON-NLS-1$
	private static final String JAVA_VERSION = "java.version"; //$NON-NLS-1$

	private static final String[] VM_PROPERTIES = {JAVA_SPEC_NAME, JAVA_SPEC_VERSION, JAVA_VERSION};
	private static final String FOUNDATION = "foundation"; //$NON-NLS-1$
	private static final Map<String, String[]> mappings = new HashMap<>();

	static {
		// table where the key is the EE and the value is an array of EEs that it is a super-set of
		mappings.put(CDC_FOUNDATION_1_0, new String[] {OSGI_MINIMUM_1_0});
		mappings.put(CDC_FOUNDATION_1_1, new String[] {CDC_FOUNDATION_1_0, OSGI_MINIMUM_1_2});
		mappings.put(OSGI_MINIMUM_1_1, new String[] {OSGI_MINIMUM_1_0});
		mappings.put(OSGI_MINIMUM_1_2, new String[] {OSGI_MINIMUM_1_1});
		mappings.put(J2SE_1_2, new String[] {JRE_1_1});
		mappings.put(J2SE_1_3, new String[] {J2SE_1_2, CDC_FOUNDATION_1_0, OSGI_MINIMUM_1_0});
		mappings.put(J2SE_1_4, new String[] {J2SE_1_3, CDC_FOUNDATION_1_1, OSGI_MINIMUM_1_2});
		mappings.put(J2SE_1_5, new String[] {J2SE_1_4});
		mappings.put(JavaSE_1_6, new String[] {J2SE_1_5});
		mappings.put(JavaSE_1_7, new String[] {JavaSE_1_6});
		mappings.put(JavaSE_1_8, new String[] { JavaSE_1_7 });
		mappings.put(JavaSE_9, new String[] { JavaSE_1_8 });
		mappings.put(JavaSE_10, new String[] { JavaSE_9 });
		mappings.put(JavaSE_10_Plus, new String[] { JavaSE_13 });
		mappings.put(JavaSE_11, new String[] { JavaSE_10 });
		mappings.put(JavaSE_12, new String[] { JavaSE_11 });
		mappings.put(JavaSE_13, new String[] { JavaSE_12 });
	}
	@Override
	public CompatibleEnvironment[] analyze(IVMInstall vm, IProgressMonitor monitor) throws CoreException {
		ArrayList<CompatibleEnvironment> result = new ArrayList<>();
		if (!(vm instanceof IVMInstall2)) {
			return new CompatibleEnvironment[0];
		}
		IVMInstall2 vm2 = (IVMInstall2) vm;
		List<String> types = null;
		if (EEVMType.ID_EE_VM_TYPE.equals(vm.getVMInstallType().getId())) {
			String eeId = ((EEVMInstall)vm).getAttribute(EEVMInstall.ATTR_EXECUTION_ENVIRONMENT_ID);
			if (eeId != null) {
				types = getTypes(eeId);
			}
		}
		if (types == null) {
			String javaVersion = vm2.getJavaVersion();
			if (javaVersion == null) {
				// We have a contributed VM type. Check to see if its a foundation VM, if we can.
				if ((vm instanceof IVMInstall3) && isFoundation1_0((IVMInstall3) vm)) {
					types = getTypes(CDC_FOUNDATION_1_0);
				} else if ((vm instanceof IVMInstall3) && isFoundation1_1((IVMInstall3) vm)) {
					types = getTypes(CDC_FOUNDATION_1_1);
				}
			} else {
				if (javaVersion.startsWith("13")) { //$NON-NLS-1$
					types = getTypes(JavaSE_13);
				} else if (javaVersion.startsWith("12")) { //$NON-NLS-1$
					types = getTypes(JavaSE_12);
				} else if (javaVersion.startsWith("11")) { //$NON-NLS-1$
					types = getTypes(JavaSE_11);
				} else if (javaVersion.startsWith("10")) { //$NON-NLS-1$
					types = getTypes(JavaSE_10);
				} else if (javaVersion.startsWith("9")) { //$NON-NLS-1$
					types = getTypes(JavaSE_9);
				} else if (javaVersion.startsWith("1.8")) { //$NON-NLS-1$
					types = getTypes(JavaSE_1_8);
				} else if (javaVersion.startsWith("1.7")) { //$NON-NLS-1$
					types = getTypes(JavaSE_1_7);
				} else if (javaVersion.startsWith("1.6")) { //$NON-NLS-1$
					types = getTypes(JavaSE_1_6);
				} else if (javaVersion.startsWith("1.5")) { //$NON-NLS-1$
					types = getTypes(J2SE_1_5);
				} else if (javaVersion.startsWith("1.4")) { //$NON-NLS-1$
					types = getTypes(J2SE_1_4);
				} else if (javaVersion.startsWith("1.3")) { //$NON-NLS-1$
					types = getTypes(J2SE_1_3);
				} else if (javaVersion.startsWith("1.2")) { //$NON-NLS-1$
					types = getTypes(J2SE_1_2);
				} else if (javaVersion.startsWith("1.1")) { //$NON-NLS-1$
					if ((vm instanceof IVMInstall3) && isFoundation1_1((IVMInstall3) vm)) {
						types = getTypes(CDC_FOUNDATION_1_1);
					} else {
						types = getTypes(JRE_1_1);
					}
				} else if (javaVersion.startsWith("1.0")) { //$NON-NLS-1$
					if ((vm instanceof IVMInstall3) && isFoundation1_0((IVMInstall3) vm)) {
						types = getTypes(CDC_FOUNDATION_1_0);
					}
				} else if (javaVersion.startsWith("1") && javaVersion.length() >= 2 && javaVersion.charAt(1) != '.') { //$NON-NLS-1$
					// At the moment only caters to versions 11 to 19.
					types = getTypes(JavaSE_10_Plus);
				}
			}
		}

		if (types != null) {
			for (int i=0; i < types.size(); i++) {
				addEnvironment(result, types.get(i), i ==0);
			}
		}
		return result.toArray(new CompatibleEnvironment[result.size()]);
	}

	/*
	 * Check a couple of known system properties for the word "foundation".
	 */
	private boolean isFoundation(Map<String, String> properties) {
		for (int i=0; i < VM_PROPERTIES.length; i++) {
			String value = properties.get(VM_PROPERTIES[i]);
			if (value == null) {
				continue;
			}
			for (StringTokenizer tokenizer = new StringTokenizer(value); tokenizer.hasMoreTokens(); ) {
				if (FOUNDATION.equalsIgnoreCase(tokenizer.nextToken())) {
					return true;
				}
			}
		}
		return false;
	}

	private boolean isFoundation1_0(IVMInstall3 vm) throws CoreException {
		Map<String, String> map = vm.evaluateSystemProperties(VM_PROPERTIES, null);
		return isFoundation(map) ? "1.0".equals(map.get(JAVA_SPEC_VERSION)) : false; //$NON-NLS-1$
	}

	private boolean isFoundation1_1(IVMInstall3 vm) throws CoreException {
		Map<String, String> map = vm.evaluateSystemProperties(VM_PROPERTIES, null);
		return isFoundation(map) ? "1.1".equals(map.get(JAVA_SPEC_VERSION)) : false; //$NON-NLS-1$
	}

	private void addEnvironment(ArrayList<CompatibleEnvironment> result, String id, boolean strict) {
		IExecutionEnvironmentsManager manager = JavaRuntime.getExecutionEnvironmentsManager();
		IExecutionEnvironment env = manager.getEnvironment(id);
		if (env != null) {
			result.add(new CompatibleEnvironment(env, strict));
		}
	}

	// first entry in the list is the perfect match
	private List<String> getTypes(String type) {
		List<String> result = new ArrayList<>();
		result.add(type);
		String[] values = mappings.get(type);
		if (values != null) {
			for (int i=0; i<values.length; i++) {
				result.addAll(getTypes(values[i]));
			}
		}
		return result;
	}

}