Back to project page alogger.
The source code is released under:
GNU General Public License
If you think the Android project alogger listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
package com.jug6ernaut.android.utilites.time; /*/*from w w w . j a v a2 s .c om*/ * Copyright (C) 2007 The Guava Authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import org.jetbrains.annotations.Nullable; /** * Simple static methods to be called at the start of your own methods to verify * correct arguments and state. This allows constructs such as * <pre> * if (count <= 0) { * throw new IllegalArgumentException("must be positive: " + count); * }</pre> * * to be replaced with the more compact * <pre> * checkArgument(count > 0, "must be positive: %s", count);</pre> * * Note that the sense of the expression is inverted; with {@code Preconditions} * you declare what you expect to be <i>true</i>, just as you do with an * <a href="http://java.sun.com/j2se/1.5.0/docs/guide/language/assert.html"> * {@code assert}</a> or a JUnit {@code assertTrue} call. * * <p><b>Warning:</b> only the {@code "%s"} specifier is recognized as a * placeholder in these messages, not the full range of {@link * String#format(String, Object[])} specifiers. * * <p>Take care not to confuse precondition checking with other similar types * of checks! Precondition exceptions -- including those provided here, but also * {@link IndexOutOfBoundsException}, {@link NoSuchElementException}, {@link * UnsupportedOperationException} and others -- are used to signal that the * <i>calling method</i> has made an error. This tells the caller that it should * not have invoked the method when it did, with the arguments it did, or * perhaps ever. Postcondition or other invariant failures should not throw * these types of exceptions. * * @author Kevin Bourrillion * @since Guava release 02 (imported from Google Collections Library) */ public final class Preconditions { private Preconditions() {} /** * Ensures the truth of an expression involving one or more parameters to the * calling method. * * @param expression a boolean expression * @throws IllegalArgumentException if {@code expression} is false */ public static void checkArgument(boolean expression) { if (!expression) { throw new IllegalArgumentException(); } } /** * Ensures the truth of an expression involving one or more parameters to the * calling method. * * @param expression a boolean expression * @param errorMessage the exception message to use if the check fails; will * be converted to a string using {@link String#valueOf(Object)} * @throws IllegalArgumentException if {@code expression} is false */ public static void checkArgument( boolean expression, @Nullable Object errorMessage) { if (!expression) { throw new IllegalArgumentException(String.valueOf(errorMessage)); } } /** * Ensures the truth of an expression involving one or more parameters to the * calling method. * * @param expression a boolean expression * @param errorMessageTemplate a template for the exception message should the * check fail. The message is formed by replacing each {@code %s} * placeholder in the template with an argument. These are matched by * position - the first {@code %s} gets {@code errorMessageArgs[0]}, etc. * Unmatched arguments will be appended to the formatted message in square * braces. Unmatched placeholders will be left as-is. * @param errorMessageArgs the arguments to be substituted into the message * template. Arguments are converted to strings using * {@link String#valueOf(Object)}. * @throws IllegalArgumentException if {@code expression} is false * @throws NullPointerException if the check fails and either {@code * errorMessageTemplate} or {@code errorMessageArgs} is null (don't let * this happen) */ public static void checkArgument(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object... errorMessageArgs) { if (!expression) { throw new IllegalArgumentException( format(errorMessageTemplate, errorMessageArgs)); } } /** * Ensures the truth of an expression involving the state of the calling * instance, but not involving any parameters to the calling method. * * @param expression a boolean expression * @throws IllegalStateException if {@code expression} is false */ public static void checkState(boolean expression) { if (!expression) { throw new IllegalStateException(); } } /** * Ensures the truth of an expression involving the state of the calling * instance, but not involving any parameters to the calling method. * * @param expression a boolean expression * @param errorMessage the exception message to use if the check fails; will * be converted to a string using {@link String#valueOf(Object)} * @throws IllegalStateException if {@code expression} is false */ public static void checkState( boolean expression, @Nullable Object errorMessage) { if (!expression) { throw new IllegalStateException(String.valueOf(errorMessage)); } } /** * Ensures the truth of an expression involving the state of the calling * instance, but not involving any parameters to the calling method. * * @param expression a boolean expression * @param errorMessageTemplate a template for the exception message should the * check fail. The message is formed by replacing each {@code %s} * placeholder in the template with an argument. These are matched by * position - the first {@code %s} gets {@code errorMessageArgs[0]}, etc. * Unmatched arguments will be appended to the formatted message in square * braces. Unmatched placeholders will be left as-is. * @param errorMessageArgs the arguments to be substituted into the message * template. Arguments are converted to strings using * {@link String#valueOf(Object)}. * @throws IllegalStateException if {@code expression} is false * @throws NullPointerException if the check fails and either {@code * errorMessageTemplate} or {@code errorMessageArgs} is null (don't let * this happen) */ public static void checkState(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object... errorMessageArgs) { if (!expression) { throw new IllegalStateException( format(errorMessageTemplate, errorMessageArgs)); } } /** * Ensures that an object reference passed as a parameter to the calling * method is not null. * * @param reference an object reference * @return the non-null reference that was validated * @throws NullPointerException if {@code reference} is null */ public static <T> T checkNotNull(T reference) { if (reference == null) { throw new NullPointerException(); } return reference; } /** * Ensures that an object reference passed as a parameter to the calling * method is not null. * * @param reference an object reference * @param errorMessage the exception message to use if the check fails; will * be converted to a string using {@link String#valueOf(Object)} * @return the non-null reference that was validated * @throws NullPointerException if {@code reference} is null */ public static <T> T checkNotNull(T reference, @Nullable Object errorMessage) { if (reference == null) { throw new NullPointerException(String.valueOf(errorMessage)); } return reference; } /** * Ensures that an object reference passed as a parameter to the calling * method is not null. * * @param reference an object reference * @param errorMessageTemplate a template for the exception message should the * check fail. The message is formed by replacing each {@code %s} * placeholder in the template with an argument. These are matched by * position - the first {@code %s} gets {@code errorMessageArgs[0]}, etc. * Unmatched arguments will be appended to the formatted message in square * braces. Unmatched placeholders will be left as-is. * @param errorMessageArgs the arguments to be substituted into the message * template. Arguments are converted to strings using * {@link String#valueOf(Object)}. * @return the non-null reference that was validated * @throws NullPointerException if {@code reference} is null */ public static <T> T checkNotNull(T reference, @Nullable String errorMessageTemplate, @Nullable Object... errorMessageArgs) { if (reference == null) { // If either of these parameters is null, the right thing happens anyway throw new NullPointerException( format(errorMessageTemplate, errorMessageArgs)); } return reference; } /* * All recent hotspots (as of 2009) *really* like to have the natural code * * if (guardExpression) { * throw new BadException(messageExpression); * } * * refactored so that messageExpression is moved to a separate * String-returning method. * * if (guardExpression) { * throw new BadException(badMsg(...)); * } * * The alternative natural refactorings into void or Exception-returning * methods are much slower. This is a big deal - we're talking factors of * 2-8 in microbenchmarks, not just 10-20%. (This is a hotspot optimizer * bug, which should be fixed, but that's a separate, big project). * * The coding pattern above is heavily used in java.util, e.g. in ArrayList. * There is a RangeCheckMicroBenchmark in the JDK that was used to test this. * * But the methods in this class want to throw different exceptions, * depending on the args, so it appears that this pattern is not directly * applicable. But we can use the ridiculous, devious trick of throwing an * exception in the middle of the construction of another exception. * Hotspot is fine with that. */ /** * Ensures that {@code index} specifies a valid <i>element</i> in an array, * list or string of size {@code size}. An element index may range from zero, * inclusive, to {@code size}, exclusive. * * @param index a user-supplied index identifying an element of an array, list * or string * @param size the size of that array, list or string * @return the value of {@code index} * @throws IndexOutOfBoundsException if {@code index} is negative or is not * less than {@code size} * @throws IllegalArgumentException if {@code size} is negative */ public static int checkElementIndex(int index, int size) { return checkElementIndex(index, size, "index"); } /** * Ensures that {@code index} specifies a valid <i>element</i> in an array, * list or string of size {@code size}. An element index may range from zero, * inclusive, to {@code size}, exclusive. * * @param index a user-supplied index identifying an element of an array, list * or string * @param size the size of that array, list or string * @param desc the text to use to describe this index in an error message * @return the value of {@code index} * @throws IndexOutOfBoundsException if {@code index} is negative or is not * less than {@code size} * @throws IllegalArgumentException if {@code size} is negative */ public static int checkElementIndex( int index, int size, @Nullable String desc) { // Carefully optimized for execution by hotspot (explanatory comment above) if (index < 0 || index >= size) { throw new IndexOutOfBoundsException(badElementIndex(index, size, desc)); } return index; } private static String badElementIndex(int index, int size, String desc) { if (index < 0) { return format("%s (%s) must not be negative", desc, index); } else if (size < 0) { throw new IllegalArgumentException("negative size: " + size); } else { // index >= size return format("%s (%s) must be less than size (%s)", desc, index, size); } } /** * Ensures that {@code index} specifies a valid <i>position</i> in an array, * list or string of size {@code size}. A position index may range from zero * to {@code size}, inclusive. * * @param index a user-supplied index identifying a position in an array, list * or string * @param size the size of that array, list or string * @return the value of {@code index} * @throws IndexOutOfBoundsException if {@code index} is negative or is * greater than {@code size} * @throws IllegalArgumentException if {@code size} is negative */ public static int checkPositionIndex(int index, int size) { return checkPositionIndex(index, size, "index"); } /** * Ensures that {@code index} specifies a valid <i>position</i> in an array, * list or string of size {@code size}. A position index may range from zero * to {@code size}, inclusive. * * @param index a user-supplied index identifying a position in an array, list * or string * @param size the size of that array, list or string * @param desc the text to use to describe this index in an error message * @return the value of {@code index} * @throws IndexOutOfBoundsException if {@code index} is negative or is * greater than {@code size} * @throws IllegalArgumentException if {@code size} is negative */ public static int checkPositionIndex( int index, int size, @Nullable String desc) { // Carefully optimized for execution by hotspot (explanatory comment above) if (index < 0 || index > size) { throw new IndexOutOfBoundsException(badPositionIndex(index, size, desc)); } return index; } private static String badPositionIndex(int index, int size, String desc) { if (index < 0) { return format("%s (%s) must not be negative", desc, index); } else if (size < 0) { throw new IllegalArgumentException("negative size: " + size); } else { // index > size return format("%s (%s) must not be greater than size (%s)", desc, index, size); } } /** * Ensures that {@code start} and {@code end} specify a valid <i>positions</i> * in an array, list or string of size {@code size}, and are in order. A * position index may range from zero to {@code size}, inclusive. * * @param start a user-supplied index identifying a starting position in an * array, list or string * @param end a user-supplied index identifying a ending position in an array, * list or string * @param size the size of that array, list or string * @throws IndexOutOfBoundsException if either index is negative or is * greater than {@code size}, or if {@code end} is less than {@code start} * @throws IllegalArgumentException if {@code size} is negative */ public static void checkPositionIndexes(int start, int end, int size) { // Carefully optimized for execution by hotspot (explanatory comment above) if (start < 0 || end < start || end > size) { throw new IndexOutOfBoundsException(badPositionIndexes(start, end, size)); } } private static String badPositionIndexes(int start, int end, int size) { if (start < 0 || start > size) { return badPositionIndex(start, size, "start index"); } if (end < 0 || end > size) { return badPositionIndex(end, size, "end index"); } // end < start return format("end index (%s) must not be less than start index (%s)", end, start); } /** * Substitutes each {@code %s} in {@code template} with an argument. These * are matched by position - the first {@code %s} gets {@code args[0]}, etc. * If there are more arguments than placeholders, the unmatched arguments will * be appended to the end of the formatted message in square braces. * * @param template a non-null string containing 0 or more {@code %s} * placeholders. * @param args the arguments to be substituted into the message * template. Arguments are converted to strings using * {@link String#valueOf(Object)}. Arguments can be null. */ static String format(String template, @Nullable Object... args) { template = String.valueOf(template); // null -> "null" // start substituting the arguments into the '%s' placeholders StringBuilder builder = new StringBuilder( template.length() + 16 * args.length); int templateStart = 0; int i = 0; while (i < args.length) { int placeholderStart = template.indexOf("%s", templateStart); if (placeholderStart == -1) { break; } builder.append(template.substring(templateStart, placeholderStart)); builder.append(args[i++]); templateStart = placeholderStart + 2; } builder.append(template.substring(templateStart)); // if we run out of placeholders, append the extra args in square braces if (i < args.length) { builder.append(" ["); builder.append(args[i++]); while (i < args.length) { builder.append(", "); builder.append(args[i++]); } builder.append(']'); } return builder.toString(); } }