diff options
author | Reinier Zwitserloot <reinier@tipit.to> | 2009-11-25 07:32:49 +0100 |
---|---|---|
committer | Reinier Zwitserloot <reinier@tipit.to> | 2009-11-25 07:32:49 +0100 |
commit | 1a0e611a9c5e1ee518670647ce1a44beae559b44 (patch) | |
tree | e5ef8f671bc6688f486e874d4e2e1a7813e4f0b2 /src/core/lombok/EqualsAndHashCode.java | |
parent | 7fd947ea40c25dad9ee543ebc4b92de9a2e05efc (diff) | |
download | lombok-1a0e611a9c5e1ee518670647ce1a44beae559b44.tar.gz lombok-1a0e611a9c5e1ee518670647ce1a44beae559b44.tar.bz2 lombok-1a0e611a9c5e1ee518670647ce1a44beae559b44.zip |
Refactored the source folders.
Diffstat (limited to 'src/core/lombok/EqualsAndHashCode.java')
-rw-r--r-- | src/core/lombok/EqualsAndHashCode.java | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/core/lombok/EqualsAndHashCode.java b/src/core/lombok/EqualsAndHashCode.java new file mode 100644 index 00000000..88d72051 --- /dev/null +++ b/src/core/lombok/EqualsAndHashCode.java @@ -0,0 +1,80 @@ +/* + * Copyright © 2009 Reinier Zwitserloot and Roel Spilker. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +package lombok; + +import java.lang.annotation.ElementType; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; +import java.lang.annotation.Target; + +/** + * Generates implementations for the {@code equals} and {@code hashCode} methods inherited by all objects. + * <p> + * If either method already exists, then {@code @EqualsAndHashCode} will not generate that particular method. + * If they all exist, {@code @EqualsAndHashCode} generates no methods, and emits a warning instead to highlight + * that its doing nothing at all. The parameter list and return type are not relevant when deciding to skip generation of + * a method; any method named {@code hashCode} will make {@code @EqualsAndHashCode} not generate that method, + * for example. + * <p> + * By default, all fields that are non-static and non-transient are used in the equality check and hashCode generation. + * You can exclude more fields by specifying them in the {@code exclude} parameter. You can also explicitly specify + * the fields that are to be used by specifying them in the {@code of} parameter. + * <p> + * Normally, auto-generating {@code hashCode} and {@code equals} implementations in a subclass is a bad idea, as + * the superclass also defines fields, for which equality checks/hashcodes won't be auto-generated. Therefore, a warning + * is emitted when you try. Instead, you can set the {@code callSuper} parameter to <em>true</em> which will call + * {@code super.equals} and {@code super.hashCode}. Doing this with {@code java.lang.Object} as superclass is + * pointless, so, conversely, setting this flag when <em>NOT</em> extending something (other than Object) will also generate + * a warning. Be aware that not all implementations of {@code equals} correctly handle being called from a subclass! + * Fortunately, lombok-generated {@code equals} implementations do correctly handle it. + * <p> + * Array fields are handled by way of {@link java.util.Arrays#deepEquals(Object[], Object[])} where necessary, as well + * as {@code deepHashCode}. The downside is that arrays with circular references (arrays that contain themselves, + * possibly indirectly) results in calls to {@code hashCode} and {@code equals} throwing a + * {@link java.lang.StackOverflowError}. However, the implementations for java's own {@link java.util.ArrayList} suffer + * from the same flaw. + */ +@Target(ElementType.TYPE) +@Retention(RetentionPolicy.SOURCE) +public @interface EqualsAndHashCode { + /** + * Any fields listed here will not be taken into account in the generated + * {@code equals} and {@code hashCode} implementations. + * Mutually exclusive with {@link #of()}. + */ + String[] exclude() default {}; + + /** + * If present, explicitly lists the fields that are to be used for identity. + * Normally, all non-static, non-transient fields are used for identity. + * <p> + * Mutually exclusive with {@link #exclude()}. + */ + String[] of() default {}; + + /** + * Call on the superclass's implementations of {@code equals} and {@code hashCode} before calculating + * for the fields in this class. + * <strong>default: false</strong> + */ + boolean callSuper() default false; +} |