sailing-analytics/java/com.googlecode.java-diff-utils/src/difflib/Delta.java

/*
   Copyright 2010 Dmitry Naumenko (dm.naumenko@gmail.com)

   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.
 */
package difflib;

import java.util.*;

/**
 * Describes the delta between original and revised texts.
 * 
 * @author <a href="dm.naumenko@gmail.com">Dmitry Naumenko</a>
 */
public abstract class Delta<T> {
    private Chunk<T> original;
    private Chunk<T> revised;
    
    public enum TYPE {
        CHANGE, DELETE, INSERT
    }
    
    /**
     * Construct the delta for original and revised chunks
     * 
     * @param original chunk describes the original text
     * @param revised chunk describes the revised text
     */
    public Delta(Chunk<T> original, Chunk<T> revised) {
        this.original = original;
        this.revised = revised;
    }
    
    /**
     * Verifies that this delta can be used to patch the given text.
     * 
     * @param target the text to patch.
     * @throws PatchFailedException if the patch cannot be applied.
     */
    public abstract void verify(List<T> target) throws PatchFailedException;
    
    /**
     * Applies this delta as the patch for a given target
     * 
     * @param target the given target
     * @throws PatchFailedException
     */
    public abstract void applyTo(List<T> target) throws PatchFailedException;
    
    /**
     * Cancel this delta for a given revised text. The action is opposite to
     * patch.
     * 
     * @param target the given revised text
     */
    public abstract void restore(List<T> target);
    
    /**
     * Returns the type of delta
     * @return the type enum
     */
    public abstract TYPE getType();
    
    /**
     * @return the Chunk describing the original text
     */
    public Chunk<T> getOriginal() {
        return original;
    }
    
    /**
     * @param original the Chunk describing the original text to set
     */
    public void setOriginal(Chunk<T> original) {
        this.original = original;
    }
    
    /**
     * @return the Chunk describing the revised text
     */
    public Chunk<T> getRevised() {
        return revised;
    }
    
    /**
     * @param revised the Chunk describing the revised text to set
     */
    public void setRevised(Chunk<T> revised) {
        this.revised = revised;
    }
    
    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((original == null) ? 0 : original.hashCode());
        result = prime * result + ((revised == null) ? 0 : revised.hashCode());
        return result;
    }
    
    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        @SuppressWarnings("unchecked")
        Delta<T> other = (Delta<T>) obj;
        if (original == null) {
            if (other.original != null)
                return false;
        } else if (!original.equals(other.original))
            return false;
        if (revised == null) {
            if (other.revised != null)
                return false;
        } else if (!revised.equals(other.revised))
            return false;
        return true;
    }
    
}