Java tutorial
/******************************************************************************* * Copyright (c) 2000, 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 * IBM Corporation - added constant AccDefault * IBM Corporation - added constants AccBridge and AccVarargs for J2SE 1.5 *******************************************************************************/ package org.eclipse.jdt.core; import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants; import org.eclipse.jdt.internal.compiler.lookup.ExtraCompilerModifiers; /** * Utility class for decoding modifier flags in Java elements. * <p> * This class provides static methods only. * </p> * <p> * Note that the numeric values of these flags match the ones for class files * as described in the Java Virtual Machine Specification (except for * {@link #AccDeprecated}, {@link #AccAnnotationDefault}, and {@link #AccDefaultMethod}). * </p> * <p> * The AST class <code>Modifier</code> provides * similar functionality as this class, only in the * <code>org.eclipse.jdt.core.dom</code> package. * </p> * * @see IMember#getFlags() * @noinstantiate This class is not intended to be instantiated by clients. */ public final class Flags { /** * Constant representing the absence of any flag. * @since 3.0 */ public static final int AccDefault = ClassFileConstants.AccDefault; /** * Public access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccPublic = ClassFileConstants.AccPublic; /** * Private access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccPrivate = ClassFileConstants.AccPrivate; /** * Protected access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccProtected = ClassFileConstants.AccProtected; /** * Static access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccStatic = ClassFileConstants.AccStatic; /** * Final access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccFinal = ClassFileConstants.AccFinal; /** * Synchronized access flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccSynchronized = ClassFileConstants.AccSynchronized; /** * Volatile property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccVolatile = ClassFileConstants.AccVolatile; /** * Transient property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccTransient = ClassFileConstants.AccTransient; /** * Native property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccNative = ClassFileConstants.AccNative; /** * Interface property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccInterface = ClassFileConstants.AccInterface; /** * Abstract property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccAbstract = ClassFileConstants.AccAbstract; /** * Strictfp property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccStrictfp = ClassFileConstants.AccStrictfp; /** * Super property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccSuper = ClassFileConstants.AccSuper; /** * Synthetic property flag. See The Java Virtual Machine Specification for more details. * @since 2.0 */ public static final int AccSynthetic = ClassFileConstants.AccSynthetic; /** * Deprecated property flag. * <p> * Note that this flag's value is internal and is not defined in the * Virtual Machine specification. * </p> * @since 2.0 */ public static final int AccDeprecated = ClassFileConstants.AccDeprecated; /** * Bridge method property flag (added in J2SE 1.5). Used to flag a compiler-generated * bridge methods. * See The Java Virtual Machine Specification for more details. * @since 3.0 */ public static final int AccBridge = ClassFileConstants.AccBridge; /** * Varargs method property flag (added in J2SE 1.5). * Used to flag variable arity method declarations. * See The Java Virtual Machine Specification for more details. * @since 3.0 */ public static final int AccVarargs = ClassFileConstants.AccVarargs; /** * Enum property flag (added in J2SE 1.5). * See The Java Virtual Machine Specification for more details. * @since 3.0 */ public static final int AccEnum = ClassFileConstants.AccEnum; /** * Annotation property flag (added in J2SE 1.5). * See The Java Virtual Machine Specification for more details. * @since 3.0 */ public static final int AccAnnotation = ClassFileConstants.AccAnnotation; /** * Default method property flag. * <p> * Note that this flag's value is internal and is not defined in the * Virtual Machine specification. * </p> * @since 3.10 */ public static final int AccDefaultMethod = ExtraCompilerModifiers.AccDefaultMethod; /** * Annotation method default property flag. * Used to flag annotation type methods that declare a default value. * <p> * Note that this flag's value is internal and is not defined in the * Virtual Machine specification. * </p> * @since 3.10 */ public static final int AccAnnotationDefault = ClassFileConstants.AccAnnotationDefault; /** * Module declaration property flag. * Used to flag a compilation unit or a class file that contains a module declaration. * * @since 3.14 */ public static final int AccModule = ClassFileConstants.AccModule; /** * Not instantiable. */ private Flags() { // Not instantiable } /** * Returns whether the given integer includes the <code>abstract</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>abstract</code> modifier is included */ public static boolean isAbstract(int flags) { return (flags & AccAbstract) != 0; } /** * Returns whether the given integer includes the indication that the * element is deprecated (<code>@deprecated</code> tag in Javadoc comment). * * @param flags the flags * @return <code>true</code> if the element is marked as deprecated */ public static boolean isDeprecated(int flags) { return (flags & AccDeprecated) != 0; } /** * Returns whether the given integer includes the <code>final</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>final</code> modifier is included */ public static boolean isFinal(int flags) { return (flags & AccFinal) != 0; } /** * Returns whether the given integer includes the <code>interface</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>interface</code> modifier is included * @since 2.0 */ public static boolean isInterface(int flags) { return (flags & AccInterface) != 0; } /** * Returns whether the given integer includes the <code>native</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>native</code> modifier is included */ public static boolean isNative(int flags) { return (flags & AccNative) != 0; } /** * Returns whether the given integer does not include one of the * <code>public</code>, <code>private</code>, or <code>protected</code> flags. * * @param flags the flags * @return <code>true</code> if no visibility flag is set * @since 3.2 */ public static boolean isPackageDefault(int flags) { return (flags & (AccPublic | AccPrivate | AccProtected)) == 0; } /** * Returns whether the given integer includes the <code>private</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>private</code> modifier is included */ public static boolean isPrivate(int flags) { return (flags & AccPrivate) != 0; } /** * Returns whether the given integer includes the <code>protected</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>protected</code> modifier is included */ public static boolean isProtected(int flags) { return (flags & AccProtected) != 0; } /** * Returns whether the given integer includes the <code>public</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>public</code> modifier is included */ public static boolean isPublic(int flags) { return (flags & AccPublic) != 0; } /** * Returns whether the given integer includes the <code>static</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>static</code> modifier is included */ public static boolean isStatic(int flags) { return (flags & AccStatic) != 0; } /** * Returns whether the given integer includes the <code>super</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>super</code> modifier is included * @since 3.2 */ public static boolean isSuper(int flags) { return (flags & AccSuper) != 0; } /** * Returns whether the given integer includes the <code>strictfp</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>strictfp</code> modifier is included */ public static boolean isStrictfp(int flags) { return (flags & AccStrictfp) != 0; } /** * Returns whether the given integer includes the <code>synchronized</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>synchronized</code> modifier is included */ public static boolean isSynchronized(int flags) { return (flags & AccSynchronized) != 0; } /** * Returns whether the given integer includes the indication that the * element is synthetic. * * @param flags the flags * @return <code>true</code> if the element is marked synthetic */ public static boolean isSynthetic(int flags) { return (flags & AccSynthetic) != 0; } /** * Returns whether the given integer includes the <code>transient</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>transient</code> modifier is included */ public static boolean isTransient(int flags) { return (flags & AccTransient) != 0; } /** * Returns whether the given integer includes the <code>volatile</code> modifier. * * @param flags the flags * @return <code>true</code> if the <code>volatile</code> modifier is included */ public static boolean isVolatile(int flags) { return (flags & AccVolatile) != 0; } /** * Returns whether the given integer has the <code>AccBridge</code> * bit set. * * @param flags the flags * @return <code>true</code> if the <code>AccBridge</code> flag is included * @see #AccBridge * @since 3.0 */ public static boolean isBridge(int flags) { return (flags & AccBridge) != 0; } /** * Returns whether the given integer has the <code>AccVarargs</code> * bit set. * * @param flags the flags * @return <code>true</code> if the <code>AccVarargs</code> flag is included * @see #AccVarargs * @since 3.0 */ public static boolean isVarargs(int flags) { return (flags & AccVarargs) != 0; } /** * Returns whether the given integer has the <code>AccEnum</code> * bit set. * * @param flags the flags * @return <code>true</code> if the <code>AccEnum</code> flag is included * @see #AccEnum * @since 3.0 */ public static boolean isEnum(int flags) { return (flags & AccEnum) != 0; } /** * Returns whether the given integer has the <code>AccAnnotation</code> * bit set. * * @param flags the flags * @return <code>true</code> if the <code>AccAnnotation</code> flag is included * @see #AccAnnotation * @since 3.0 */ public static boolean isAnnotation(int flags) { return (flags & AccAnnotation) != 0; } /** * Returns whether the given integer has the <code>AccDefaultMethod</code> * bit set. Note that this flag represents the usage of the 'default' keyword * on a method and should not be confused with the 'package' access visibility (which used to be called 'default access'). * * @return <code>true</code> if the <code>AccDefaultMethod</code> flag is included * @see #AccDefaultMethod * @since 3.10 */ public static boolean isDefaultMethod(int flags) { return (flags & AccDefaultMethod) != 0; } /** * Returns whether the given integer has the <code>AccAnnnotationDefault</code> * bit set. * * @return <code>true</code> if the <code>AccAnnotationDefault</code> flag is included * @see #AccAnnotationDefault * @since 3.10 */ public static boolean isAnnnotationDefault(int flags) { return (flags & AccAnnotationDefault) != 0; } /** * Returns whether the given integer has the <code>AccModule</code> * bit set. * * @return <code>true</code> if the <code>AccModule</code> flag is included * @see #AccModule * @since 3.14 */ public static boolean isModule(int flags) { return (flags & AccModule) != 0; } /** * Returns a standard string describing the given modifier flags. * Only modifier flags are included in the output; deprecated, * synthetic, bridge, etc. flags are ignored. * <p> * The flags are output in the following order: * <pre> public protected private * abstract default static final synchronized native strictfp transient volatile</pre> * <p> * This order is consistent with the recommendations in JLS8 ("*Modifier:" rules in chapters 8 and 9). * </p> * <p> * Note that the flags of a method can include the AccVarargs flag that has no standard description. Since the AccVarargs flag has the same value as * the AccTransient flag (valid for fields only), attempting to get the description of method modifiers with the AccVarargs flag set would result in an * unexpected description. Clients should ensure that the AccVarargs is not included in the flags of a method as follows: * <pre> * IMethod method = ... * int flags = method.getFlags() & ~Flags.AccVarargs; * return Flags.toString(flags); * </pre> * <p> * Examples results: * <pre> * <code>"public static final"</code> * <code>"private native"</code> * </pre> * * @param flags the flags * @return the standard string representation of the given flags */ public static String toString(int flags) { StringBuffer sb = new StringBuffer(); if (isPublic(flags)) sb.append("public "); //$NON-NLS-1$ if (isProtected(flags)) sb.append("protected "); //$NON-NLS-1$ if (isPrivate(flags)) sb.append("private "); //$NON-NLS-1$ if (isAbstract(flags)) sb.append("abstract "); //$NON-NLS-1$ if (isDefaultMethod(flags)) sb.append("default "); //$NON-NLS-1$ if (isStatic(flags)) sb.append("static "); //$NON-NLS-1$ if (isFinal(flags)) sb.append("final "); //$NON-NLS-1$ if (isSynchronized(flags)) sb.append("synchronized "); //$NON-NLS-1$ if (isNative(flags)) sb.append("native "); //$NON-NLS-1$ if (isStrictfp(flags)) sb.append("strictfp "); //$NON-NLS-1$ if (isTransient(flags)) sb.append("transient "); //$NON-NLS-1$ if (isVolatile(flags)) sb.append("volatile "); //$NON-NLS-1$ int len = sb.length(); if (len == 0) return ""; //$NON-NLS-1$ sb.setLength(len - 1); return sb.toString(); } }